Merge android-4.4.129 (b1c4836) into msm-4.4

* refs/heads/tmp-b1c4836
  Linux 4.4.129
  writeback: safer lock nesting
  fanotify: fix logic of events on child
  ext4: bugfix for mmaped pages in mpage_release_unused_pages()
  mm/filemap.c: fix NULL pointer in page_cache_tree_insert()
  mm: allow GFP_{FS,IO} for page_cache_read page cache allocation
  autofs: mount point create should honour passed in mode
  Don't leak MNT_INTERNAL away from internal mounts
  rpc_pipefs: fix double-dput()
  hypfs_kill_super(): deal with failed allocations
  jffs2_kill_sb(): deal with failed allocations
  powerpc/lib: Fix off-by-one in alternate feature patching
  powerpc/eeh: Fix enabling bridge MMIO windows
  MIPS: memset.S: Fix clobber of v1 in last_fixup
  MIPS: memset.S: Fix return of __clear_user from Lpartial_fixup
  MIPS: memset.S: EVA & fault support for small_memset
  MIPS: uaccess: Add micromips clobbers to bzero invocation
  HID: hidraw: Fix crash on HIDIOCGFEATURE with a destroyed device
  ALSA: hda - New VIA controller suppor no-snoop path
  ALSA: rawmidi: Fix missing input substream checks in compat ioctls
  ALSA: line6: Use correct endpoint type for midi output
  ext4: fix deadlock between inline_data and ext4_expand_extra_isize_ea()
  ext4: fix crashes in dioread_nolock mode
  drm/radeon: Fix PCIe lane width calculation
  ext4: don't allow r/w mounts if metadata blocks overlap the superblock
  vfio/pci: Virtualize Maximum Read Request Size
  vfio/pci: Virtualize Maximum Payload Size
  vfio-pci: Virtualize PCIe & AF FLR
  ALSA: pcm: Fix endless loop for XRUN recovery in OSS emulation
  ALSA: pcm: Fix mutex unbalance in OSS emulation ioctls
  ALSA: pcm: Return -EBUSY for OSS ioctls changing busy streams
  ALSA: pcm: Avoid potential races between OSS ioctls and read/write
  ALSA: pcm: Use ERESTARTSYS instead of EINTR in OSS emulation
  ALSA: oss: consolidate kmalloc/memset 0 call to kzalloc
  watchdog: f71808e_wdt: Fix WD_EN register read
  thermal: imx: Fix race condition in imx_thermal_probe()
  clk: bcm2835: De-assert/assert PLL reset signal when appropriate
  clk: mvebu: armada-38x: add support for missing clocks
  clk: mvebu: armada-38x: add support for 1866MHz variants
  mmc: jz4740: Fix race condition in IRQ mask update
  iommu/vt-d: Fix a potential memory leak
  um: Use POSIX ucontext_t instead of struct ucontext
  dmaengine: at_xdmac: fix rare residue corruption
  IB/srp: Fix completion vector assignment algorithm
  IB/srp: Fix srp_abort()
  ALSA: pcm: Fix UAF at PCM release via PCM timer access
  RDMA/ucma: Don't allow setting RDMA_OPTION_IB_PATH without an RDMA device
  ext4: fail ext4_iget for root directory if unallocated
  ext4: don't update checksum of new initialized bitmaps
  jbd2: if the journal is aborted then don't allow update of the log tail
  random: use a tighter cap in credit_entropy_bits_safe()
  thunderbolt: Resume control channel after hibernation image is created
  ASoC: ssm2602: Replace reg_default_raw with reg_default
  HID: core: Fix size as type u32
  HID: Fix hid_report_len usage
  powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops
  powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops
  powerpc/64: Fix smp_wmb barrier definition use use lwsync consistently
  powerpc/powernv: Handle unknown OPAL errors in opal_nvram_write()
  HID: i2c-hid: fix size check and type usage
  usb: dwc3: pci: Properly cleanup resource
  USB:fix USB3 devices behind USB3 hubs not resuming at hibernate thaw
  ACPI / hotplug / PCI: Check presence of slot itself in get_slot_status()
  ACPI / video: Add quirk to force acpi-video backlight on Samsung 670Z5E
  regmap: Fix reversed bounds check in regmap_raw_write()
  xen-netfront: Fix hang on device removal
  ARM: dts: at91: sama5d4: fix pinctrl compatible string
  ARM: dts: at91: at91sam9g25: fix mux-mask pinctrl property
  usb: musb: gadget: misplaced out of bounds check
  mm, slab: reschedule cache_reap() on the same CPU
  ipc/shm: fix use-after-free of shm file via remap_file_pages()
  resource: fix integer overflow at reallocation
  fs/reiserfs/journal.c: add missing resierfs_warning() arg
  ubi: Reject MLC NAND
  ubi: Fix error for write access
  ubi: fastmap: Don't flush fastmap work on detach
  ubifs: Check ubifs_wbuf_sync() return code
  tty: make n_tty_read() always abort if hangup is in progress
  x86/hweight: Don't clobber %rdi
  x86/hweight: Get rid of the special calling convention
  lan78xx: Correctly indicate invalid OTP
  slip: Check if rstate is initialized before uncompressing
  cdc_ether: flag the Cinterion AHS8 modem by gemalto as WWAN
  hwmon: (ina2xx) Fix access to uninitialized mutex
  rtl8187: Fix NULL pointer dereference in priv->conf_mutex
  getname_kernel() needs to make sure that ->name != ->iname in long case
  s390/ipl: ensure loadparm valid flag is set
  s390/qdio: don't merge ERROR output buffers
  s390/qdio: don't retry EQBS after CCQ 96
  block/loop: fix deadlock after loop_set_status
  Revert "perf tests: Decompress kernel module before objdump"
  radeon: hide pointless #warning when compile testing
  perf intel-pt: Fix timestamp following overflow
  perf intel-pt: Fix error recovery from missing TIP packet
  perf intel-pt: Fix sync_switch
  perf intel-pt: Fix overlap detection to identify consecutive buffers correctly
  parisc: Fix out of array access in match_pci_device()
  media: v4l2-compat-ioctl32: don't oops on overlay
  f2fs: check cap_resource only for data blocks
  Revert "f2fs: introduce f2fs_set_page_dirty_nobuffer"
  f2fs: clear PageError on writepage
  UPSTREAM: timer: Export destroy_hrtimer_on_stack()
  BACKPORT: dm verity: add 'check_at_most_once' option to only validate hashes once
  f2fs: call unlock_new_inode() before d_instantiate()
  f2fs: refactor read path to allow multiple postprocessing steps
  fscrypt: allow synchronous bio decryption

Change-Id: I45f4ac10734d92023b53118d83dcd6c83974a283
Signed-off-by: Srinivasarao P <spathi@codeaurora.org>

1 files changed, 20 insertions, 3 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index 09267be8d27b..9fa852a6473b 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -198,6 +198,12 @@ static int __shm_open(struct vm_area_struct *vma)
 	if (IS_ERR(shp))
 		return PTR_ERR(shp);
 
+	if (shp->shm_file != sfd->file) {
+		/* ID was reused */
+		shm_unlock(shp);
+		return -EINVAL;
+	}
+
 	shp->shm_atim = get_seconds();
 	shp->shm_lprid = task_tgid_vnr(current);
 	shp->shm_nattch++;
@@ -414,8 +420,9 @@ static int shm_mmap(struct file *file, struct vm_area_struct *vma)
 	int ret;
 
 	/*
-	 * In case of remap_file_pages() emulation, the file can represent
-	 * removed IPC ID: propogate shm_lock() error to caller.
+	 * In case of remap_file_pages() emulation, the file can represent an
+	 * IPC ID that was removed, and possibly even reused by another shm
+	 * segment already.  Propagate this case as an error to caller.
 	 */
 	ret =__shm_open(vma);
 	if (ret)
@@ -439,6 +446,7 @@ static int shm_release(struct inode *ino, struct file *file)
 	struct shm_file_data *sfd = shm_file_data(file);
 
 	put_ipc_ns(sfd->ns);
+	fput(sfd->file);
 	shm_file_data(file) = NULL;
 	kfree(sfd);
 	return 0;
@@ -1198,7 +1206,16 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
 	file->f_mapping = shp->shm_file->f_mapping;
 	sfd->id = shp->shm_perm.id;
 	sfd->ns = get_ipc_ns(ns);
-	sfd->file = shp->shm_file;
+	/*
+	 * We need to take a reference to the real shm file to prevent the
+	 * pointer from becoming stale in cases where the lifetime of the outer
+	 * file extends beyond that of the shm segment.  It's not usually
+	 * possible, but it can happen during remap_file_pages() emulation as
+	 * that unmaps the memory, then does ->mmap() via file reference only.
+	 * We'll deny the ->mmap() if the shm segment was since removed, but to
+	 * detect shm ID reuse we need to compare the file pointers.
+	 */
+	sfd->file = get_file(shp->shm_file);
 	sfd->vm_ops = NULL;
 
 	err = security_mmap_file(file, prot, flags);