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* bpf: Fix bpf_redirect to an ipip/ip6tnl devMartin KaFai Lau2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the bpf program calls bpf_redirect(dev, 0) and dev is an ipip/ip6tnl, it currently includes the mac header. e.g. If dev is ipip, the end result is IP-EthHdr-IP instead of IP-IP. The fix is to pull the mac header. At ingress, skb_postpull_rcsum() is not needed because the ethhdr should have been pulled once already and then got pushed back just before calling the bpf_prog. At egress, this patch calls skb_postpull_rcsum(). If bpf_redirect(dev, BPF_F_INGRESS) is called, it also fails now because it calls dev_forward_skb() which eventually calls eth_type_trans(skb, dev). The eth_type_trans() will set skb->type = PACKET_OTHERHOST because the mac address does not match the redirecting dev->dev_addr. The PACKET_OTHERHOST will eventually cause the ip_rcv() errors out. To fix this, ____dev_forward_skb() is added. Joint work with Daniel Borkmann. Fixes: cfc7381b3002 ("ip_tunnel: add collect_md mode to IPIP tunnel") Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels") Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@fb.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* cgroup: Add task_under_cgroup_hierarchy cgroup inline function to headersSargun Dhillon2022-04-19
| | | | | | | | | | | | | | This commit adds an inline function to cgroup.h to check whether a given task is under a given cgroup hierarchy. This is to avoid having to put ifdefs in .c files to gate access to cgroups. When cgroups are disabled this always returns true. Signed-off-by: Sargun Dhillon <sargun@sargun.me> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Tejun Heo <tj@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf, events: fix offset in skb copy handlerDaniel Borkmann2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes the __output_custom() routine we currently use with bpf_skb_copy(). I missed that when len is larger than the size of the current handle, we can issue multiple invocations of copy_func, and __output_custom() advances destination but also source buffer by the written amount of bytes. When we have __output_custom(), this is actually wrong since in that case the source buffer points to a non-linear object, in our case an skb, which the copy_func helper is supposed to walk. Therefore, since this is non-linear we thus need to pass the offset into the helper, so that copy_func can use it for extracting the data from the source object. Therefore, adjust the callback signatures properly and pass offset into the skb_header_pointer() invoked from bpf_skb_copy() callback. The __DEFINE_OUTPUT_COPY_BODY() is adjusted to accommodate for two things: i) to pass in whether we should advance source buffer or not; this is a compile-time constant condition, ii) to pass in the offset for __output_custom(), which we do with help of __VA_ARGS__, so everything can stay inlined as is currently. Both changes allow for adapting the __output_* fast-path helpers w/o extra overhead. Fixes: 555c8a8623a3 ("bpf: avoid stack copy and use skb ctx for event output") Fixes: 7e3f977edd0b ("perf, events: add non-linear data support for raw records") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* perf, events: add non-linear data support for raw recordsDaniel Borkmann2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds support for non-linear data on raw records. It extends raw records to have one or multiple fragments that will be written linearly into the ring slot, where each fragment can optionally have a custom callback handler to walk and extract complex, possibly non-linear data. If a callback handler is provided for a fragment, then the new __output_custom() will be used instead of __output_copy() for the perf_output_sample() part. perf_prepare_sample() does all the size calculation only once, so perf_output_sample() doesn't need to redo the same work anymore, meaning real_size and padding will be cached in the raw record. The raw record becomes 32 bytes in size without holes; to not increase it further and to avoid doing unnecessary recalculations in fast-path, we can reuse next pointer of the last fragment, idea here is borrowed from ZERO_OR_NULL_PTR(), which should keep the perf_output_sample() path for PERF_SAMPLE_RAW minimal. This facility is needed for BPF's event output helper as a first user that will, in a follow-up, add an additional perf_raw_frag to its perf_raw_record in order to be able to more efficiently dump skb context after a linear head meta data related to it. skbs can be non-linear and thus need a custom output function to dump buffers. Currently, the skb data needs to be copied twice; with the help of __output_custom() this work only needs to be done once. Future users could be things like XDP/BPF programs that work on different context though and would thus also have a different callback function. The few users of raw records are adapted to initialize their frag data from the raw record itself, no change in behavior for them. The code is based upon a PoC diff provided by Peter Zijlstra [1]. [1] http://thread.gmane.org/gmane.linux.network/421294 Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64KDaniel Borkmann2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit fdadd04931c2d7cd294dc5b2b342863f94be53a3 ] Michael and Sandipan report: Commit ede95a63b5 introduced a bpf_jit_limit tuneable to limit BPF JIT allocations. At compile time it defaults to PAGE_SIZE * 40000, and is adjusted again at init time if MODULES_VADDR is defined. For ppc64 kernels, MODULES_VADDR isn't defined, so we're stuck with the compile-time default at boot-time, which is 0x9c400000 when using 64K page size. This overflows the signed 32-bit bpf_jit_limit value: root@ubuntu:/tmp# cat /proc/sys/net/core/bpf_jit_limit -1673527296 and can cause various unexpected failures throughout the network stack. In one case `strace dhclient eth0` reported: setsockopt(5, SOL_SOCKET, SO_ATTACH_FILTER, {len=11, filter=0x105dd27f8}, 16) = -1 ENOTSUPP (Unknown error 524) and similar failures can be seen with tools like tcpdump. This doesn't always reproduce however, and I'm not sure why. The more consistent failure I've seen is an Ubuntu 18.04 KVM guest booted on a POWER9 host would time out on systemd/netplan configuring a virtio-net NIC with no noticeable errors in the logs. Given this and also given that in near future some architectures like arm64 will have a custom area for BPF JIT image allocations we should get rid of the BPF_JIT_LIMIT_DEFAULT fallback / default entirely. For 4.21, we have an overridable bpf_jit_alloc_exec(), bpf_jit_free_exec() so therefore add another overridable bpf_jit_alloc_exec_limit() helper function which returns the possible size of the memory area for deriving the default heuristic in bpf_jit_charge_init(). Like bpf_jit_alloc_exec() and bpf_jit_free_exec(), the new bpf_jit_alloc_exec_limit() assumes that module_alloc() is the default JIT memory provider, and therefore in case archs implement their custom module_alloc() we use MODULES_{END,_VADDR} for limits and otherwise for vmalloc_exec() cases like on ppc64 we use VMALLOC_{END,_START}. Additionally, for archs supporting large page sizes, we should change the sysctl to be handled as long to not run into sysctl restrictions in future. Fixes: ede95a63b5e8 ("bpf: add bpf_jit_limit knob to restrict unpriv allocations") Reported-by: Sandipan Das <sandipan@linux.ibm.com> Reported-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup: Add generic cgroup subsystem permission checksColin Cross2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | Rather than using explicit euid == 0 checks when trying to move tasks into a cgroup via CFS, move permission checks into each specific cgroup subsystem. If a subsystem does not specify a 'allow_attach' handler, then we fall back to doing our checks the old way. Use the 'allow_attach' handler for the 'cpu' cgroup to allow non-root processes to add arbitrary processes to a 'cpu' cgroup if it has the CAP_SYS_NICE capability set. This version of the patch adds a 'allow_attach' handler instead of reusing the 'can_attach' handler. If the 'can_attach' handler is reused, a new cgroup that implements 'can_attach' but not the permission checks could end up with no permission checks at all. Change-Id: Icfa950aa9321d1ceba362061d32dc7dfa2c64f0c Original-Author: San Mehat <san@google.com> Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup: refactor allow_attach function into common codeRom Lemarchand2022-04-19
| | | | | | | | | | | move cpu_cgroup_allow_attach to a common subsys_cgroup_allow_attach. This allows any process with CAP_SYS_NICE to move tasks across cgroups if they use this function as their allow_attach handler. Bug: 18260435 Change-Id: I6bb4933d07e889d0dc39e33b4e71320c34a2c90f Signed-off-by: Rom Lemarchand <romlem@android.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* FROMLIST: kernel: cgroup: add poll file operationJohannes Weiner2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cgroup has a standardized poll/notification mechanism for waking all pollers on all fds when a filesystem node changes. To allow polling for custom events, add a .poll callback that can override the default. This is in preparation for pollable cgroup pressure files which have per-fd trigger configurations. Link: http://lkml.kernel.org/r/20190124211518.244221-3-surenb@google.com Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> (in linux-next: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=c88177361203be291a49956b6c9d5ec164ea24b2) Conflicts: include/linux/cgroup-defs.h kernel/cgroup.c 1. made changes in kernel/cgroup.c instead of kernel/cgroup/cgroup.c 2. replaced __poll_t with unsigned int Bug: 111308141 Test: modified lmkd to use PSI and tested using lmkd_unit_test Change-Id: Ie3d914197d1f150e1d83c6206865566a7cbff1b4 Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* UPSTREAM: cgroup add cftype->open/release() callbacksTejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | Pipe the newly added kernfs->open/release() callbacks through cftype. While at it, as cleanup operations now can be performed from ->release() instead of ->seq_stop(), make the latter optional. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Acked-by: Zefan Li <lizefan@huawei.com> (cherry picked from commit e90cbebc3fa5caea4c8bfeb0d0157a0cee53efc7) Bug: 111308141 Test: modified lmkd to use PSI and tested using lmkd_unit_test Change-Id: Iff9794cbbc2c7067c24cb2f767bbdeffa26b5180 Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup: fix cgroup_sk_alloc() for sk_clone_lock()Cong Wang2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit ad0f75e5f57ccbceec13274e1e242f2b5a6397ed ] When we clone a socket in sk_clone_lock(), its sk_cgrp_data is copied, so the cgroup refcnt must be taken too. And, unlike the sk_alloc() path, sock_update_netprioidx() is not called here. Therefore, it is safe and necessary to grab the cgroup refcnt even when cgroup_sk_alloc is disabled. sk_clone_lock() is in BH context anyway, the in_interrupt() would terminate this function if called there. And for sk_alloc() skcd->val is always zero. So it's safe to factor out the code to make it more readable. The global variable 'cgroup_sk_alloc_disabled' is used to determine whether to take these reference counts. It is impossible to make the reference counting correct unless we save this bit of information in skcd->val. So, add a new bit there to record whether the socket has already taken the reference counts. This obviously relies on kmalloc() to align cgroup pointers to at least 4 bytes, ARCH_KMALLOC_MINALIGN is certainly larger than that. This bug seems to be introduced since the beginning, commit d979a39d7242 ("cgroup: duplicate cgroup reference when cloning sockets") tried to fix it but not compeletely. It seems not easy to trigger until the recent commit 090e28b229af ("netprio_cgroup: Fix unlimited memory leak of v2 cgroups") was merged. Fixes: bd1060a1d671 ("sock, cgroup: add sock->sk_cgroup") Reported-by: Cameron Berkenpas <cam@neo-zeon.de> Reported-by: Peter Geis <pgwipeout@gmail.com> Reported-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> Reported-by: Daniël Sonck <dsonck92@gmail.com> Reported-by: Zhang Qiang <qiang.zhang@windriver.com> Tested-by: Cameron Berkenpas <cam@neo-zeon.de> Tested-by: Peter Geis <pgwipeout@gmail.com> Tested-by: Thomas Lamprecht <t.lamprecht@proxmox.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Zefan Li <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: UPSTREAM: Add a helper function to get socket cookie in eBPFChenbo Feng2022-04-19
| | | | | | | | | | | | | | | | | | | Cherrypick from commit: 91b8270f2a4d1d9b268de90451cdca63a70052d6 Retrieve the socket cookie generated by sock_gen_cookie() from a sk_buff with a known socket. Generates a new cookie if one was not yet set.If the socket pointer inside sk_buff is NULL, 0 is returned. The helper function coud be useful in monitoring per socket networking traffic statistics and provide a unique socket identifier per namespace. Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Bug: 30950746 Change-Id: I95918dcc3ceffb3061495a859d28aee88e3cde3c Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* net: simplify and make pkt_type_ok() available for other usersJamal Hadi Salim2022-04-19
| | | | | | | | Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* kernfs: define kernfs_node_dentryAditya Kali2022-04-19
| | | | | | | | | | | Add a new kernfs api is added to lookup the dentry for a particular kernfs path. Signed-off-by: Aditya Kali <adityakali@google.com> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: cgroup: misc changesTejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Misc trivial changes to prepare for future changes. No functional difference. * Expose cgroup_get(), cgroup_tryget() and cgroup_parent(). * Implement task_dfl_cgroup() which dereferences css_set->dfl_cgrp. * Rename cgroup_stats_show() to cgroup_stat_show() for consistency with the file name. Signed-off-by: Tejun Heo <tj@kernel.org> (cherry picked from commit 3e48930cc74f0c212ee1838f89ad0ca7fcf2fea1) Conflicts: kernel/cgroup/cgroup.c (1. manual merge because kernel/cgroup/cgroup.c is under kernel/cgroup.c 2. cgroup_stats_show change is skipped because the function dos not exist) Bug: 111308141 Test: modified lmkd to use PSI and tested using lmkd_unit_test Signed-off-by: Suren Baghdasaryan <surenb@google.com> Change-Id: I756ee3dcf0d0f3da69cd1b58e644271625053538 Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* objtool, modules: Discard objtool annotation sections for modulesJosh Poimboeuf2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | commit e390f9a9689a42f477a6073e2e7df530a4c1b740 upstream. The '__unreachable' and '__func_stack_frame_non_standard' sections are only used at compile time. They're discarded for vmlinux but they should also be discarded for modules. Since this is a recurring pattern, prefix the section names with ".discard.". It's a nice convention and vmlinux.lds.h already discards such sections. Also remove the 'a' (allocatable) flag from the __unreachable section since it doesn't make sense for a discarded section. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Jessica Yu <jeyu@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends") Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble Signed-off-by: Ingo Molnar <mingo@kernel.org> [dwmw2: Remove the unreachable part in backporting since it's not here yet] Signed-off-by: David Woodhouse <dwmw@amazon.co.ku> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* objtool: Add STACK_FRAME_NON_STANDARD() macroJosh Poimboeuf2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | Add a new macro, STACK_FRAME_NON_STANDARD(), which is used to denote a function which does something unusual related to its stack frame. Use of the macro prevents objtool from emitting a false positive warning. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris J Arges <chris.j.arges@canonical.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Pedro Alves <palves@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/34487a17b23dba43c50941599d47054a9584b219.1456719558.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* remove leftovers from 6ea07b4590d3174a53303Anay Wadhera2022-04-19
| | | | Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* fs: Add user namespace member to struct super_blockEric W. Biederman2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Start marking filesystems with a user namespace owner, s_user_ns. In this change this is only used for permission checks of who may mount a filesystem. Ultimately s_user_ns will be used for translating ids and checking capabilities for filesystems mounted from user namespaces. The default policy for setting s_user_ns is implemented in sget(), which arranges for s_user_ns to be set to current_user_ns() and to ensure that the mounter of the filesystem has CAP_SYS_ADMIN in that user_ns. The guts of sget are split out into another function sget_userns(). The function sget_userns calls alloc_super with the specified user namespace or it verifies the existing superblock that was found has the expected user namespace, and fails with EBUSY when it is not. This failing prevents users with the wrong privileges mounting a filesystem. The reason for the split of sget_userns from sget is that in some cases such as mount_ns and kernfs_mount_ns a different policy for permission checking of mounts and setting s_user_ns is necessary, and the existence of sget_userns() allows those policies to be implemented. The helper mount_ns is expected to be used for filesystems such as proc and mqueuefs which present per namespace information. The function mount_ns is modified to call sget_userns instead of sget to ensure the user namespace owner of the namespace whose information is presented by the filesystem is used on the superblock. For sysfs and cgroup the appropriate permission checks are already in place, and kernfs_mount_ns is modified to call sget_userns so that the init_user_ns is the only user namespace used. For the cgroup filesystem cgroup namespace mounts are bind mounts of a subset of the full cgroup filesystem and as such s_user_ns must be the same for all of them as there is only a single superblock. Mounts of sysfs that vary based on the network namespace could in principle change s_user_ns but it keeps the analysis and implementation of kernfs simpler if that is not supported, and at present there appear to be no benefits from supporting a different s_user_ns on any sysfs mount. Getting the details of setting s_user_ns correct has been a long process. Thanks to Pavel Tikhorirorv who spotted a leak in sget_userns. Thanks to Seth Forshee who has kept the work alive. Thanks-to: Seth Forshee <seth.forshee@canonical.com> Thanks-to: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* vfs: Pass data, ns, and ns->userns to mount_nsEric W. Biederman2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today what is normally called data (the mount options) is not passed to fill_super through mount_ns. Pass the mount options and the namespace separately to mount_ns so that filesystems such as proc that have mount options, can use mount_ns. Pass the user namespace to mount_ns so that the standard permission check that verifies the mounter has permissions over the namespace can be performed in mount_ns instead of in each filesystems .mount method. Thus removing the duplication between mqueuefs and proc in terms of permission checks. The extra permission check does not currently affect the rpc_pipefs filesystem and the nfsd filesystem as those filesystems do not currently allow unprivileged mounts. Without unpvileged mounts it is guaranteed that the caller has already passed capable(CAP_SYS_ADMIN) which guarantees extra permission check will pass. Update rpc_pipefs and the nfsd filesystem to ensure that the network namespace reference is always taken in fill_super and always put in kill_sb so that the logic is simpler and so that errors originating inside of fill_super do not cause a network namespace leak. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* kernfs: make kernfs_path*() behave in the style of strlcpy()Tejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | kernfs_path*() functions always return the length of the full path but the path content is undefined if the length is larger than the provided buffer. This makes its behavior different from strlcpy() and requires error handling in all its users even when they don't care about truncation. In addition, the implementation can actully be simplified by making it behave properly in strlcpy() style. * Update kernfs_path_from_node_locked() to always fill up the buffer with path. If the buffer is not large enough, the output is truncated and terminated. * kernfs_path() no longer needs error handling. Make it a simple inline wrapper around kernfs_path_from_node(). * sysfs_warn_dup()'s use of kernfs_path() doesn't need error handling. Updated accordingly. * cgroup_path()'s use of kernfs_path() updated to retain the old behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: bpf: permit multiple bpf attachments for a single perf eventYonghong Song2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch enables multiple bpf attachments for a kprobe/uprobe/tracepoint single trace event. Each trace_event keeps a list of attached perf events. When an event happens, all attached bpf programs will be executed based on the order of attachment. A global bpf_event_mutex lock is introduced to protect prog_array attaching and detaching. An alternative will be introduce a mutex lock in every trace_event_call structure, but it takes a lot of extra memory. So a global bpf_event_mutex lock is a good compromise. The bpf prog detachment involves allocation of memory. If the allocation fails, a dummy do-nothing program will replace to-be-detached program in-place. Signed-off-by: Yonghong Song <yhs@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> (cherry picked from commit e87c6bc3852b981e71c757be20771546ce9f76f3) Signed-off-by: Connor O'Brien <connoro@google.com> Bug: 121213201 Bug: 138317270 Test: build & boot cuttlefish; attach 2 progs to 1 tracepoint Change-Id: I390d8c0146888ddb1aed5a6f6e5dae7ef394ebc9 Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* perf, bpf: minimize the size of perf_trace_() tracepoint handlerAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | move trace_call_bpf() into helper function to minimize the size of perf_trace_*() tracepoint handlers. text data bss dec hex filename 10541679 5526646 2945024 19013349 1221ee5 vmlinux_before 10509422 5526646 2945024 18981092 121a0e4 vmlinux_after It may seem that perf_fetch_caller_regs() can also be moved, but that is incorrect, since ip/sp will be wrong. bpf+tracepoint performance is not affected, since perf_swevent_put_recursion_context() is now inlined. export_symbol_gpl can also be dropped. No measurable change in normal perf tracepoints. Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: bpf: multi program support for cgroup+bpfAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | introduce BPF_F_ALLOW_MULTI flag that can be used to attach multiple bpf programs to a cgroup. The difference between three possible flags for BPF_PROG_ATTACH command: - NONE(default): No further bpf programs allowed in the subtree. - BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program, the program in this cgroup yields to sub-cgroup program. - BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program, that cgroup program gets run in addition to the program in this cgroup. NONE and BPF_F_ALLOW_OVERRIDE existed before. This patch doesn't change their behavior. It only clarifies the semantics in relation to new flag. Only one program is allowed to be attached to a cgroup with NONE or BPF_F_ALLOW_OVERRIDE flag. Multiple programs are allowed to be attached to a cgroup with BPF_F_ALLOW_MULTI flag. They are executed in FIFO order (those that were attached first, run first) The programs of sub-cgroup are executed first, then programs of this cgroup and then programs of parent cgroup. All eligible programs are executed regardless of return code from earlier programs. To allow efficient execution of multiple programs attached to a cgroup and to avoid penalizing cgroups without any programs attached introduce 'struct bpf_prog_array' which is RCU protected array of pointers to bpf programs. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> for cgroup bits Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> (cherry picked from commit 324bda9e6c5add86ba2e1066476481c48132aca0) Signed-off-by: Connor O'Brien <connoro@google.com> Bug: 121213201 Bug: 138317270 Test: build & boot cuttlefish Change-Id: I06b71c850b9f3e052b106abab7a4a3add012a3f8 Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: add bpf_jit_limit knob to restrict unpriv allocationsDaniel Borkmann2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ede95a63b5e84ddeea6b0c473b36ab8bfd8c6ce3 upstream. Rick reported that the BPF JIT could potentially fill the entire module space with BPF programs from unprivileged users which would prevent later attempts to load normal kernel modules or privileged BPF programs, for example. If JIT was enabled but unsuccessful to generate the image, then before commit 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config") we would always fall back to the BPF interpreter. Nowadays in the case where the CONFIG_BPF_JIT_ALWAYS_ON could be set, then the load will abort with a failure since the BPF interpreter was compiled out. Add a global limit and enforce it for unprivileged users such that in case of BPF interpreter compiled out we fail once the limit has been reached or we fall back to BPF interpreter earlier w/o using module mem if latter was compiled in. In a next step, fair share among unprivileged users can be resolved in particular for the case where we would fail hard once limit is reached. Fixes: 290af86629b2 ("bpf: introduce BPF_JIT_ALWAYS_ON config") Fixes: 0a14842f5a3c ("net: filter: Just In Time compiler for x86-64") Co-Developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: LKML <linux-kernel@vger.kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: convert htab map to hlist_nullsAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | commit 4fe8435909fddc97b81472026aa954e06dd192a5 upstream. when all map elements are pre-allocated one cpu can delete and reuse htab_elem while another cpu is still walking the hlist. In such case the lookup may miss the element. Convert hlist to hlist_nulls to avoid such scenario. When bucket lock is taken there is no need to take such precautions, so only convert map_lookup and map_get_next to nulls. The race window is extremely small and only reproducible with explicit udelay() inside lookup_nulls_elem_raw() Similar to hlist add hlist_nulls_for_each_entry_safe() and hlist_nulls_entry_safe() helpers. Fixes: 6c9059817432 ("bpf: pre-allocate hash map elements") Reported-by: Jonathan Perry <jonperry@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chenbo Feng <fengc@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: Prevent memory disambiguation attackAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit af86ca4e3088fe5eacf2f7e58c01fa68ca067672 upstream. Detect code patterns where malicious 'speculative store bypass' can be used and sanitize such patterns. 39: (bf) r3 = r10 40: (07) r3 += -216 41: (79) r8 = *(u64 *)(r7 +0) // slow read 42: (7a) *(u64 *)(r10 -72) = 0 // verifier inserts this instruction 43: (7b) *(u64 *)(r8 +0) = r3 // this store becomes slow due to r8 44: (79) r1 = *(u64 *)(r6 +0) // cpu speculatively executes this load 45: (71) r2 = *(u8 *)(r1 +0) // speculatively arbitrary 'load byte' // is now sanitized Above code after x86 JIT becomes: e5: mov %rbp,%rdx e8: add $0xffffffffffffff28,%rdx ef: mov 0x0(%r13),%r14 f3: movq $0x0,-0x48(%rbp) fb: mov %rdx,0x0(%r14) ff: mov 0x0(%rbx),%rdi 103: movzbq 0x0(%rdi),%rsi Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bwh: Backported to 4.9: - Add bpf_verifier_env parameter to check_stack_write() - Look up stack slot_types with state->stack_slot_type[] rather than state->stack[].slot_type[] - Drop bpf_verifier_env argument to verbose() - Adjust context] Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: fix "netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of ↵Al Viro2022-04-19
| | | | | | | | | | | | | | | | | | | | 'xt_bpf_info_v1'" Descriptor table is a shared object; it's not a place where you can stick temporary references to files, especially when we don't need an opened file at all. Cc: stable@vger.kernel.org # v4.14 Fixes: 98589a0998b8 ("netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'") Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Chenbo Feng <fengc@google.com> Removed the code related to function bpf_prog_get_ok() since it is not exsit in current android tree. (cherry picked from commit 040ee69226f8a96b7943645d68f41d5d44b5ff7d) Change-Id: If7a602128cdea4b4b50c8effb215c9bca7449515 Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* UPSTREAM: netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1'Shmulik Ladkani2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 2c16d6033264 ("netfilter: xt_bpf: support ebpf") introduced support for attaching an eBPF object by an fd, with the 'bpf_mt_check_v1' ABI expecting the '.fd' to be specified upon each IPT_SO_SET_REPLACE call. However this breaks subsequent iptables calls: # iptables -A INPUT -m bpf --object-pinned /sys/fs/bpf/xxx -j ACCEPT # iptables -A INPUT -s 5.6.7.8 -j ACCEPT iptables: Invalid argument. Run `dmesg' for more information. That's because iptables works by loading existing rules using IPT_SO_GET_ENTRIES to userspace, then issuing IPT_SO_SET_REPLACE with the replacement set. However, the loaded 'xt_bpf_info_v1' has an arbitrary '.fd' number (from the initial "iptables -m bpf" invocation) - so when 2nd invocation occurs, userspace passes a bogus fd number, which leads to 'bpf_mt_check_v1' to fail. One suggested solution [1] was to hack iptables userspace, to perform a "entries fixup" immediatley after IPT_SO_GET_ENTRIES, by opening a new, process-local fd per every 'xt_bpf_info_v1' entry seen. However, in [2] both Pablo Neira Ayuso and Willem de Bruijn suggested to depricate the xt_bpf_info_v1 ABI dealing with pinned ebpf objects. This fix changes the XT_BPF_MODE_FD_PINNED behavior to ignore the given '.fd' and instead perform an in-kernel lookup for the bpf object given the provided '.path'. It also defines an alias for the XT_BPF_MODE_FD_PINNED mode, named XT_BPF_MODE_PATH_PINNED, to better reflect the fact that the user is expected to provide the path of the pinned object. Existing XT_BPF_MODE_FD_ELF behavior (non-pinned fd mode) is preserved. References: [1] https://marc.info/?l=netfilter-devel&m=150564724607440&w=2 [2] https://marc.info/?l=netfilter-devel&m=150575727129880&w=2 Reported-by: Rafael Buchbinder <rafi@rbk.ms> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Chenbo Feng <fengc@google.com> (cherry picked from commit 98589a0998b8b13c4a8fa1ccb0e62751a019faa5) Change-Id: Ia0d15a76823cca3afb38786a3d2c25c13ccf941d Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* perf, bpf: add perf events core support for BPF_PROG_TYPE_PERF_EVENT programsAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow attaching BPF_PROG_TYPE_PERF_EVENT programs to sw and hw perf events via overflow_handler mechanism. When program is attached the overflow_handlers become stacked. The program acts as a filter. Returning zero from the program means that the normal perf_event_output handler will not be called and sampling event won't be stored in the ring buffer. The overflow_handler_context==NULL is an additional safety check to make sure programs are not attached to hw breakpoints and watchdog in case other checks (that prevent that now anyway) get accidentally relaxed in the future. The program refcnt is incremented in case perf_events are inhereted when target task is forked. Similar to kprobe and tracepoint programs there is no ioctl to detach the program or swap already attached program. The user space expected to close(perf_event_fd) like it does right now for kprobe+bpf. That restriction simplifies the code quite a bit. The invocation of overflow_handler in __perf_event_overflow() is now done via READ_ONCE, since that pointer can be replaced when the program is attached while perf_event itself could have been active already. There is no need to do similar treatment for event->prog, since it's assigned only once before it's accessed. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* perf/core: Set event's default ::overflow_handler()Wang Nan2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Set a default event->overflow_handler in perf_event_alloc() so don't need to check event->overflow_handler in __perf_event_overflow(). Following commits can give a different default overflow_handler. Initial idea comes from Peter: http://lkml.kernel.org/r/20130708121557.GA17211@twins.programming.kicks-ass.net Since the default value of event->overflow_handler is not NULL, existing 'if (!overflow_handler)' checks need to be changed. is_default_overflow_handler() is introduced for this. No extra performance overhead is introduced into the hot path because in the original code we still need to read this handler from memory. A conditional branch is avoided so actually we remove some instructions. Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <pi3orama@163.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Zefan Li <lizefan@huawei.com> Link: http://lkml.kernel.org/r/1459147292-239310-3-git-send-email-wangnan0@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: prevent out-of-bounds speculationAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit b2157399cc9898260d6031c5bfe45fe137c1fbe7 upstream. Under speculation, CPUs may mis-predict branches in bounds checks. Thus, memory accesses under a bounds check may be speculated even if the bounds check fails, providing a primitive for building a side channel. To avoid leaking kernel data round up array-based maps and mask the index after bounds check, so speculated load with out of bounds index will load either valid value from the array or zero from the padded area. Unconditionally mask index for all array types even when max_entries are not rounded to power of 2 for root user. When map is created by unpriv user generate a sequence of bpf insns that includes AND operation to make sure that JITed code includes the same 'index & index_mask' operation. If prog_array map is created by unpriv user replace bpf_tail_call(ctx, map, index); with if (index >= max_entries) { index &= map->index_mask; bpf_tail_call(ctx, map, index); } (along with roundup to power 2) to prevent out-of-bounds speculation. There is secondary redundant 'if (index >= max_entries)' in the interpreter and in all JITs, but they can be optimized later if necessary. Other array-like maps (cpumap, devmap, sockmap, perf_event_array, cgroup_array) cannot be used by unpriv, so no changes there. That fixes bpf side of "Variant 1: bounds check bypass (CVE-2017-5753)" on all architectures with and without JIT. v2->v3: Daniel noticed that attack potentially can be crafted via syscall commands without loading the program, so add masking to those paths as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Slaby <jslaby@suse.cz> [ Backported to 4.9 - gregkh ] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: fix branch pruning logicAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit c131187db2d3fa2f8bf32fdf4e9a4ef805168467 ] when the verifier detects that register contains a runtime constant and it's compared with another constant it will prune exploration of the branch that is guaranteed not to be taken at runtime. This is all correct, but malicious program may be constructed in such a way that it always has a constant comparison and the other branch is never taken under any conditions. In this case such path through the program will not be explored by the verifier. It won't be taken at run-time either, but since all instructions are JITed the malicious program may cause JITs to complain about using reserved fields, etc. To fix the issue we have to track the instructions explored by the verifier and sanitize instructions that are dead at run time with NOPs. We cannot reject such dead code, since llvm generates it for valid C code, since it doesn't do as much data flow analysis as the verifier does. Fixes: 17a5267067f3 ("bpf: verifier (add verifier core)") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* UPSTREAM: selinux: bpf: Add addtional check for bpf object file receiveChenbo Feng2022-04-19
| | | | | | | | | | | | | | | | | | | | | Introduce a bpf object related check when sending and receiving files through unix domain socket as well as binder. It checks if the receiving process have privilege to read/write the bpf map or use the bpf program. This check is necessary because the bpf maps and programs are using a anonymous inode as their shared inode so the normal way of checking the files and sockets when passing between processes cannot work properly on eBPF object. This check only works when the BPF_SYSCALL is configured. Signed-off-by: Chenbo Feng <fengc@google.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Reviewed-by: James Morris <james.l.morris@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> (cherry-pick from net-next: f66e448cfda021b0bcd884f26709796fe19c7cc1) Bug: 30950746 Change-Id: I5b2cf4ccb4eab7eda91ddd7091d6aa3e7ed9f2cd Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: security: bpf: Add LSM hooks for bpf object related syscallChenbo Feng2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | Introduce several LSM hooks for the syscalls that will allow the userspace to access to eBPF object such as eBPF programs and eBPF maps. The security check is aimed to enforce a per object security protection for eBPF object so only processes with the right priviliges can read/write to a specific map or use a specific eBPF program. Besides that, a general security hook is added before the multiplexer of bpf syscall to check the cmd and the attribute used for the command. The actual security module can decide which command need to be checked and how the cmd should be checked. Signed-off-by: Chenbo Feng <fengc@google.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Added the LIST_HEAD_INIT call for security hooks, it nolonger exist in uptream code. (cherry-pick from net-next: afdb09c720b62b8090584c11151d856df330e57d) Bug: 30950746 Change-Id: Ieb3ac74392f531735fc7c949b83346a5f587a77b Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: bpf: Add file mode configuration into bpf mapsChenbo Feng2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | Introduce the map read/write flags to the eBPF syscalls that returns the map fd. The flags is used to set up the file mode when construct a new file descriptor for bpf maps. To not break the backward capability, the f_flags is set to O_RDWR if the flag passed by syscall is 0. Otherwise it should be O_RDONLY or O_WRONLY. When the userspace want to modify or read the map content, it will check the file mode to see if it is allowed to make the change. Signed-off-by: Chenbo Feng <fengc@google.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> Deleted the file mode configuration code in unsupported map type and removed the file mode check in non-existing helper functions. (cherry-pick from net-next: 6e71b04a82248ccf13a94b85cbc674a9fefe53f5) Bug: 30950746 Change-Id: Icfad20f1abb77f91068d244fb0d87fa40824dd1b Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: fix mixed signed/unsigned derived min/max value boundsDaniel Borkmann2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit 4cabc5b186b5427b9ee5a7495172542af105f02b ] Edward reported that there's an issue in min/max value bounds tracking when signed and unsigned compares both provide hints on limits when having unknown variables. E.g. a program such as the following should have been rejected: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (18) r1 = 0xffff8a94cda93400 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+7 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp 7: (7a) *(u64 *)(r10 -16) = -8 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = -1 10: (2d) if r1 > r2 goto pc+3 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=0 R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 11: (65) if r1 s> 0x1 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=0,max_value=1 R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 12: (0f) r0 += r1 13: (72) *(u8 *)(r0 +0) = 0 R0=map_value_adj(ks=8,vs=8,id=0),min_value=0,max_value=1 R1=inv,min_value=0,max_value=1 R2=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 14: (b7) r0 = 0 15: (95) exit What happens is that in the first part ... 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = -1 10: (2d) if r1 > r2 goto pc+3 ... r1 carries an unsigned value, and is compared as unsigned against a register carrying an immediate. Verifier deduces in reg_set_min_max() that since the compare is unsigned and operation is greater than (>), that in the fall-through/false case, r1's minimum bound must be 0 and maximum bound must be r2. Latter is larger than the bound and thus max value is reset back to being 'invalid' aka BPF_REGISTER_MAX_RANGE. Thus, r1 state is now 'R1=inv,min_value=0'. The subsequent test ... 11: (65) if r1 s> 0x1 goto pc+2 ... is a signed compare of r1 with immediate value 1. Here, verifier deduces in reg_set_min_max() that since the compare is signed this time and operation is greater than (>), that in the fall-through/false case, we can deduce that r1's maximum bound must be 1, meaning with prior test, we result in r1 having the following state: R1=inv,min_value=0,max_value=1. Given that the actual value this holds is -8, the bounds are wrongly deduced. When this is being added to r0 which holds the map_value(_adj) type, then subsequent store access in above case will go through check_mem_access() which invokes check_map_access_adj(), that will then probe whether the map memory is in bounds based on the min_value and max_value as well as access size since the actual unknown value is min_value <= x <= max_value; commit fce366a9dd0d ("bpf, verifier: fix alu ops against map_value{, _adj} register types") provides some more explanation on the semantics. It's worth to note in this context that in the current code, min_value and max_value tracking are used for two things, i) dynamic map value access via check_map_access_adj() and since commit 06c1c049721a ("bpf: allow helpers access to variable memory") ii) also enforced at check_helper_mem_access() when passing a memory address (pointer to packet, map value, stack) and length pair to a helper and the length in this case is an unknown value defining an access range through min_value/max_value in that case. The min_value/max_value tracking is /not/ used in the direct packet access case to track ranges. However, the issue also affects case ii), for example, the following crafted program based on the same principle must be rejected as well: 0: (b7) r2 = 0 1: (bf) r3 = r10 2: (07) r3 += -512 3: (7a) *(u64 *)(r10 -16) = -8 4: (79) r4 = *(u64 *)(r10 -16) 5: (b7) r6 = -1 6: (2d) if r4 > r6 goto pc+5 R1=ctx R2=imm0,min_value=0,max_value=0,min_align=2147483648 R3=fp-512 R4=inv,min_value=0 R6=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 7: (65) if r4 s> 0x1 goto pc+4 R1=ctx R2=imm0,min_value=0,max_value=0,min_align=2147483648 R3=fp-512 R4=inv,min_value=0,max_value=1 R6=imm-1,max_value=18446744073709551615,min_align=1 R10=fp 8: (07) r4 += 1 9: (b7) r5 = 0 10: (6a) *(u16 *)(r10 -512) = 0 11: (85) call bpf_skb_load_bytes#26 12: (b7) r0 = 0 13: (95) exit Meaning, while we initialize the max_value stack slot that the verifier thinks we access in the [1,2] range, in reality we pass -7 as length which is interpreted as u32 in the helper. Thus, this issue is relevant also for the case of helper ranges. Resetting both bounds in check_reg_overflow() in case only one of them exceeds limits is also not enough as similar test can be created that uses values which are within range, thus also here learned min value in r1 is incorrect when mixed with later signed test to create a range: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (18) r1 = 0xffff880ad081fa00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+7 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp 7: (7a) *(u64 *)(r10 -16) = -8 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = 2 10: (3d) if r2 >= r1 goto pc+3 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 11: (65) if r1 s> 0x4 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3,max_value=4 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 12: (0f) r0 += r1 13: (72) *(u8 *)(r0 +0) = 0 R0=map_value_adj(ks=8,vs=8,id=0),min_value=3,max_value=4 R1=inv,min_value=3,max_value=4 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 14: (b7) r0 = 0 15: (95) exit This leaves us with two options for fixing this: i) to invalidate all prior learned information once we switch signed context, ii) to track min/max signed and unsigned boundaries separately as done in [0]. (Given latter introduces major changes throughout the whole verifier, it's rather net-next material, thus this patch follows option i), meaning we can derive bounds either from only signed tests or only unsigned tests.) There is still the case of adjust_reg_min_max_vals(), where we adjust bounds on ALU operations, meaning programs like the following where boundaries on the reg get mixed in context later on when bounds are merged on the dst reg must get rejected, too: 0: (7a) *(u64 *)(r10 -8) = 0 1: (bf) r2 = r10 2: (07) r2 += -8 3: (18) r1 = 0xffff89b2bf87ce00 5: (85) call bpf_map_lookup_elem#1 6: (15) if r0 == 0x0 goto pc+6 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R10=fp 7: (7a) *(u64 *)(r10 -16) = -8 8: (79) r1 = *(u64 *)(r10 -16) 9: (b7) r2 = 2 10: (3d) if r2 >= r1 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R10=fp 11: (b7) r7 = 1 12: (65) if r7 s> 0x0 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=imm1,max_value=0 R10=fp 13: (b7) r0 = 0 14: (95) exit from 12 to 15: R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=imm1,min_value=1 R10=fp 15: (0f) r7 += r1 16: (65) if r7 s> 0x4 goto pc+2 R0=map_value(ks=8,vs=8,id=0),min_value=0,max_value=0 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=inv,min_value=4,max_value=4 R10=fp 17: (0f) r0 += r7 18: (72) *(u8 *)(r0 +0) = 0 R0=map_value_adj(ks=8,vs=8,id=0),min_value=4,max_value=4 R1=inv,min_value=3 R2=imm2,min_value=2,max_value=2,min_align=2 R7=inv,min_value=4,max_value=4 R10=fp 19: (b7) r0 = 0 20: (95) exit Meaning, in adjust_reg_min_max_vals() we must also reset range values on the dst when src/dst registers have mixed signed/ unsigned derived min/max value bounds with one unbounded value as otherwise they can be added together deducing false boundaries. Once both boundaries are established from either ALU ops or compare operations w/o mixing signed/unsigned insns, then they can safely be added to other regs also having both boundaries established. Adding regs with one unbounded side to a map value where the bounded side has been learned w/o mixing ops is possible, but the resulting map value won't recover from that, meaning such op is considered invalid on the time of actual access. Invalid bounds are set on the dst reg in case i) src reg, or ii) in case dst reg already had them. The only way to recover would be to perform i) ALU ops but only 'add' is allowed on map value types or ii) comparisons, but these are disallowed on pointers in case they span a range. This is fine as only BPF_JEQ and BPF_JNE may be performed on PTR_TO_MAP_VALUE_OR_NULL registers which potentially turn them into PTR_TO_MAP_VALUE type depending on the branch, so only here min/max value cannot be invalidated for them. In terms of state pruning, value_from_signed is considered as well in states_equal() when dealing with adjusted map values. With regards to breaking existing programs, there is a small risk, but use-cases are rather quite narrow where this could occur and mixing compares probably unlikely. Joint work with Josef and Edward. [0] https://lists.iovisor.org/pipermail/iovisor-dev/2017-June/000822.html Fixes: 484611357c19 ("bpf: allow access into map value arrays") Reported-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* bpf: don't trigger OOM killer under pressure with map allocDaniel Borkmann2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit d407bd25a204bd66b7346dde24bd3d37ef0e0b05 ] This patch adds two helpers, bpf_map_area_alloc() and bpf_map_area_free(), that are to be used for map allocations. Using kmalloc() for very large allocations can cause excessive work within the page allocator, so i) fall back earlier to vmalloc() when the attempt is considered costly anyway, and even more importantly ii) don't trigger OOM killer with any of the allocators. Since this is based on a user space request, for example, when creating maps with element pre-allocation, we really want such requests to fail instead of killing other user space processes. Also, don't spam the kernel log with warnings should any of the allocations fail under pressure. Given that, we can make backend selection in bpf_map_area_alloc() generic, and convert all maps over to use this API for spots with potentially large allocation requests. Note, replacing the one kmalloc_array() is fine as overflow checks happen earlier in htab_map_alloc(), since it must also protect the multiplication for vmalloc() should kmalloc_array() fail. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: bpf: introduce BPF_F_ALLOW_OVERRIDE flagAlexei Starovoitov2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If BPF_F_ALLOW_OVERRIDE flag is used in BPF_PROG_ATTACH command to the given cgroup the descendent cgroup will be able to override effective bpf program that was inherited from this cgroup. By default it's not passed, therefore override is disallowed. Examples: 1. prog X attached to /A with default prog Y fails to attach to /A/B and /A/B/C Everything under /A runs prog X 2. prog X attached to /A with allow_override. prog Y fails to attach to /A/B with default (non-override) prog M attached to /A/B with allow_override. Everything under /A/B runs prog M only. 3. prog X attached to /A with allow_override. prog Y fails to attach to /A with default. The user has to detach first to switch the mode. In the future this behavior may be extended with a chain of non-overridable programs. Also fix the bug where detach from cgroup where nothing is attached was not throwing error. Return ENOENT in such case. Add several testcases and adjust libbpf. Fixes: 3007098494be ("cgroup: add support for eBPF programs") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Daniel Mack <daniel@zonque.org> Signed-off-by: David S. Miller <davem@davemloft.net> Fixes: Change-Id: I3df35d8d3b1261503f9b5bcd90b18c9358f1ac28        ("cgroup: add support for eBPF programs") [AmitP: Refactored original patch for android-4.9 where libbpf sources are in samples/bpf/ and test_cgrp2_attach2, test_cgrp2_sock, and test_cgrp2_sock2 sample tests do not exist.] (cherry picked from commit 7f677633379b4abb3281cdbe7e7006f049305c03) Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* kernfs: implement kernfs_walk_and_get()Tejun Heo2022-04-19
| | | | | | | | | | | | | Implement kernfs_walk_and_get() which is similar to kernfs_find_and_get() but can walk a path instead of just a name. v2: Use strlcpy() instead of strlen() + memcpy() as suggested by David. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: David Miller <davem@davemloft.net> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* BACKPORT: fs: kernfs: add poll file operationJohannes Weiner2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "psi: pressure stall monitors", v3. Android is adopting psi to detect and remedy memory pressure that results in stuttering and decreased responsiveness on mobile devices. Psi gives us the stall information, but because we're dealing with latencies in the millisecond range, periodically reading the pressure files to detect stalls in a timely fashion is not feasible. Psi also doesn't aggregate its averages at a high enough frequency right now. This patch series extends the psi interface such that users can configure sensitive latency thresholds and use poll() and friends to be notified when these are breached. As high-frequency aggregation is costly, it implements an aggregation method that is optimized for fast, short-interval averaging, and makes the aggregation frequency adaptive, such that high-frequency updates only happen while monitored stall events are actively occurring. With these patches applied, Android can monitor for, and ward off, mounting memory shortages before they cause problems for the user. For example, using memory stall monitors in userspace low memory killer daemon (lmkd) we can detect mounting pressure and kill less important processes before device becomes visibly sluggish. In our memory stress testing psi memory monitors produce roughly 10x less false positives compared to vmpressure signals. Having ability to specify multiple triggers for the same psi metric allows other parts of Android framework to monitor memory state of the device and act accordingly. The new interface is straightforward. The user opens one of the pressure files for writing and writes a trigger description into the file descriptor that defines the stall state - some or full, and the maximum stall time over a given window of time. E.g.: /* Signal when stall time exceeds 100ms of a 1s window */ char trigger[] = "full 100000 1000000"; fd = open("/proc/pressure/memory"); write(fd, trigger, sizeof(trigger)); while (poll() >= 0) { ... } close(fd); When the monitored stall state is entered, psi adapts its aggregation frequency according to what the configured time window requires in order to emit event signals in a timely fashion. Once the stalling subsides, aggregation reverts back to normal. The trigger is associated with the open file descriptor. To stop monitoring, the user only needs to close the file descriptor and the trigger is discarded. Patches 1-4 prepare the psi code for polling support. Patch 5 implements the adaptive polling logic, the pressure growth detection optimized for short intervals, and hooks up write() and poll() on the pressure files. The patches were developed in collaboration with Johannes Weiner. This patch (of 5): Kernfs has a standardized poll/notification mechanism for waking all pollers on all fds when a filesystem node changes. To allow polling for custom events, add a .poll callback that can override the default. This is in preparation for pollable cgroup pressure files which have per-fd trigger configurations. Link: http://lkml.kernel.org/r/20190124211518.244221-2-surenb@google.com Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> (cherry picked from commit: 147e1a97c4a0bdd43f55a582a9416bb9092563a9) Conflicts: fs/kernfs/file.c include/linux/kernfs.h 1. replaced __poll_t with unsigned int. 2. replaced kernfs_dentry_node() with dentry->d_fsdata 3. replaced EPOLLERR/EPOLLPRI with POLLERR/POLLPRI (values are the same) Bug: 127712811 Test: lmkd in PSI mode Change-Id: Ic2bed334d05aec62f4e695f263893c3057921c55 Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* UPSTREAM: kernfs: add kernfs_ops->open/release() callbacksTejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | | | Add ->open/release() methods to kernfs_ops. ->open() is called when the file is opened and ->release() when the file is either released or severed. These callbacks can be used, for example, to manage persistent caching objects over multiple seq_file iterations. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Acked-by: Zefan Li <lizefan@huawei.com> (cherry picked from commit 0e67db2f9fe91937e798e3d7d22c50a8438187e1) Bug: 111308141 Test: modified lmkd to use PSI and tested using lmkd_unit_test Change-Id: Id06e9d5c6da1280bcdd4dc86309dcfaf52b8f9a4 Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* kernfs: Add API to generate relative kernfs pathAditya Kali2022-04-19
| | | | | | | | | | | The new function kernfs_path_from_node() generates and returns kernfs path of a given kernfs_node relative to a given parent kernfs_node. Signed-off-by: Aditya Kali <adityakali@google.com> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* UPSTREAM: cgroup: add support for eBPF programsDaniel Mack2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cherry-pick from commit 3007098494bec614fb55dee7bc0410bb7db5ad18 This patch adds two sets of eBPF program pointers to struct cgroup. One for such that are directly pinned to a cgroup, and one for such that are effective for it. To illustrate the logic behind that, assume the following example cgroup hierarchy. A - B - C \ D - E If only B has a program attached, it will be effective for B, C, D and E. If D then attaches a program itself, that will be effective for both D and E, and the program in B will only affect B and C. Only one program of a given type is effective for a cgroup. Attaching and detaching programs will be done through the bpf(2) syscall. For now, ingress and egress inet socket filtering are the only supported use-cases. Signed-off-by: Daniel Mack <daniel@zonque.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Bug: 30950746 Change-Id: I3df35d8d3b1261503f9b5bcd90b18c9358f1ac28 Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* kernel: add a helper to get an owning user namespace for a namespaceAndrey Vagin2022-04-19
| | | | | | | | | | | | | | | | Return -EPERM if an owning user namespace is outside of a process current user namespace. v2: In a first version ns_get_owner returned ENOENT for init_user_ns. This special cases was removed from this version. There is nothing outside of init_user_ns, so we can return EPERM. v3: rename ns->get_owner() to ns->owner(). get_* usually means that it grabs a reference. Acked-by: Serge Hallyn <serge@hallyn.com> Signed-off-by: Andrei Vagin <avagin@openvz.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* fs: Limit file caps to the user namespace of the super blockSeth Forshee2022-04-19
| | | | | | | | | | | | | | | | | | | Capability sets attached to files must be ignored except in the user namespaces where the mounter is privileged, i.e. s_user_ns and its descendants. Otherwise a vector exists for gaining privileges in namespaces where a user is not already privileged. Add a new helper function, current_in_user_ns(), to test whether a user namespace is the same as or a descendant of another namespace. Use this helper to determine whether a file's capability set should be applied to the caps constructed during exec. --EWB Replaced in_userns with the simpler current_in_userns. Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup: make cgroup_path() and friends behave in the style of strlcpy()Tejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup_path() and friends used to format the path from the end and thus the resulting path usually didn't start at the start of the passed in buffer. Also, when the buffer was too small, the partial result was truncated from the head rather than tail and there was no way to tell how long the full path would be. These make the functions less robust and more awkward to use. With recent updates to kernfs_path(), cgroup_path() and friends can be made to behave in strlcpy() style. * cgroup_path(), cgroup_path_ns[_locked]() and task_cgroup_path() now always return the length of the full path. If buffer is too small, it contains nul terminated truncated output. * All users updated accordingly. v2: cgroup_path() usage in kernel/sched/debug.c converted. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com> Change-Id: Ibb5c7544237e0ab6cde03c8bec80b3376917c0a8
* cgroup: Add cgroup_get_from_fdMartin KaFai Lau2022-04-19
| | | | | | | | | | | | | | Add a helper function to get a cgroup2 from a fd. It will be stored in a bpf array (BPF_MAP_TYPE_CGROUP_ARRAY) which will be introduced in the later patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Tejun Heo <tj@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup, kernfs: make mountinfo show properly scoped path for cgroup namespacesSerge E. Hallyn2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch summary: When showing a cgroupfs entry in mountinfo, show the path of the mount root dentry relative to the reader's cgroup namespace root. Short explanation (courtesy of mkerrisk): If we create a new cgroup namespace, then we want both /proc/self/cgroup and /proc/self/mountinfo to show cgroup paths that are correctly virtualized with respect to the cgroup mount point. Previous to this patch, /proc/self/cgroup shows the right info, but /proc/self/mountinfo does not. Long version: When a uid 0 task which is in freezer cgroup /a/b, unshares a new cgroup namespace, and then mounts a new instance of the freezer cgroup, the new mount will be rooted at /a/b. The root dentry field of the mountinfo entry will show '/a/b'. cat > /tmp/do1 << EOF mount -t cgroup -o freezer freezer /mnt grep freezer /proc/self/mountinfo EOF unshare -Gm bash /tmp/do1 > 330 160 0:34 / /sys/fs/cgroup/freezer rw,nosuid,nodev,noexec,relatime - cgroup cgroup rw,freezer > 355 133 0:34 /a/b /mnt rw,relatime - cgroup freezer rw,freezer The task's freezer cgroup entry in /proc/self/cgroup will simply show '/': grep freezer /proc/self/cgroup 9:freezer:/ If instead the same task simply bind mounts the /a/b cgroup directory, the resulting mountinfo entry will again show /a/b for the dentry root. However in this case the task will find its own cgroup at /mnt/a/b, not at /mnt: mount --bind /sys/fs/cgroup/freezer/a/b /mnt 130 25 0:34 /a/b /mnt rw,nosuid,nodev,noexec,relatime shared:21 - cgroup cgroup rw,freezer In other words, there is no way for the task to know, based on what is in mountinfo, which cgroup directory is its own. Example (by mkerrisk): First, a little script to save some typing and verbiage: echo -e "\t/proc/self/cgroup:\t$(cat /proc/self/cgroup | grep freezer)" cat /proc/self/mountinfo | grep freezer | awk '{print "\tmountinfo:\t\t" $4 "\t" $5}' Create cgroup, place this shell into the cgroup, and look at the state of the /proc files: 2653 2653 # Our shell 14254 # cat(1) /proc/self/cgroup: 10:freezer:/a/b mountinfo: / /sys/fs/cgroup/freezer Create a shell in new cgroup and mount namespaces. The act of creating a new cgroup namespace causes the process's current cgroups directories to become its cgroup root directories. (Here, I'm using my own version of the "unshare" utility, which takes the same options as the util-linux version): Look at the state of the /proc files: /proc/self/cgroup: 10:freezer:/ mountinfo: / /sys/fs/cgroup/freezer The third entry in /proc/self/cgroup (the pathname of the cgroup inside the hierarchy) is correctly virtualized w.r.t. the cgroup namespace, which is rooted at /a/b in the outer namespace. However, the info in /proc/self/mountinfo is not for this cgroup namespace, since we are seeing a duplicate of the mount from the old mount namespace, and the info there does not correspond to the new cgroup namespace. However, trying to create a new mount still doesn't show us the right information in mountinfo: # propagating to other mountns /proc/self/cgroup: 7:freezer:/ mountinfo: /a/b /mnt/freezer The act of creating a new cgroup namespace caused the process's current freezer directory, "/a/b", to become its cgroup freezer root directory. In other words, the pathname directory of the directory within the newly mounted cgroup filesystem should be "/", but mountinfo wrongly shows us "/a/b". The consequence of this is that the process in the cgroup namespace cannot correctly construct the pathname of its cgroup root directory from the information in /proc/PID/mountinfo. With this patch, the dentry root field in mountinfo is shown relative to the reader's cgroup namespace. So the same steps as above: /proc/self/cgroup: 10:freezer:/a/b mountinfo: / /sys/fs/cgroup/freezer /proc/self/cgroup: 10:freezer:/ mountinfo: /../.. /sys/fs/cgroup/freezer /proc/self/cgroup: 10:freezer:/ mountinfo: / /mnt/freezer cgroup.clone_children freezer.parent_freezing freezer.state tasks cgroup.procs freezer.self_freezing notify_on_release 3164 2653 # First shell that placed in this cgroup 3164 # Shell started by 'unshare' 14197 # cat(1) Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com> Tested-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup: implement cgroup_subsys->implicit_on_dflTejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | | Some controllers, perf_event for now and possibly freezer in the future, don't really make sense to control explicitly through "cgroup.subtree_control". For example, the primary role of perf_event is identifying the cgroups of tasks; however, because the controller also keeps a small amount of state per cgroup, it can't be replaced with simple cgroup membership tests. This patch implements cgroup_subsys->implicit_on_dfl flag. When set, the controller is implicitly enabled on all cgroups on the v2 hierarchy so that utility type controllers such as perf_event can be enabled and function transparently. An implicit controller doesn't show up in "cgroup.controllers" or "cgroup.subtree_control", is exempt from no internal process rule and can be stolen from the default hierarchy even if there are non-root csses. v2: Reimplemented on top of the recent updates to css handling and subsystem rebinding. Rebinding implicit subsystems is now a simple matter of exempting it from the busy subsystem check. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
* cgroup: use css_set->mg_dst_cgrp for the migration target cgroupTejun Heo2022-04-19
| | | | | | | | | | | | | | | | | | | | | | | | | Migration can be multi-target on the default hierarchy when a controller is enabled - processes belonging to each child cgroup have to be moved to the child cgroup itself to refresh css association. This isn't a problem for cgroup_migrate_add_src() as each source css_set still maps to single source and target cgroups; however, cgroup_migrate_prepare_dst() is called once after all source css_sets are added and thus might not have a single destination cgroup. This is currently worked around by specifying NULL for @dst_cgrp and using the source's default cgroup as destination as the only multi-target migration in use is self-targetting. While this works, it's subtle and clunky. As all taget cgroups are already specified while preparing the source css_sets, this clunkiness can easily be removed by recording the target cgroup in each source css_set. This patch adds css_set->mg_dst_cgrp which is recorded on cgroup_migrate_src() and used by cgroup_migrate_prepare_dst(). This also makes migration code ready for arbitrary multi-target migration. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
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