diff options
author | Jann Horn <jannh@google.com> | 2016-04-26 22:26:26 +0200 |
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committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:50:12 +0300 |
commit | c16c3d51c5001b9baab6d5f1cc2acb6c8b83b034 (patch) | |
tree | 1ce9255f9badeadfa6a875bb273371149b0f00d3 /kernel/bpf/stackmap.c | |
parent | ad1638f493fc30cc81bc16c2fa4fa46109b8a4af (diff) |
bpf: fix double-fdput in replace_map_fd_with_map_ptr()
When bpf(BPF_PROG_LOAD, ...) was invoked with a BPF program whose bytecode
references a non-map file descriptor as a map file descriptor, the error
handling code called fdput() twice instead of once (in __bpf_map_get() and
in replace_map_fd_with_map_ptr()). If the file descriptor table of the
current task is shared, this causes f_count to be decremented too much,
allowing the struct file to be freed while it is still in use
(use-after-free). This can be exploited to gain root privileges by an
unprivileged user.
This bug was introduced in
commit 0246e64d9a5f ("bpf: handle pseudo BPF_LD_IMM64 insn"), but is only
exploitable since
commit 1be7f75d1668 ("bpf: enable non-root eBPF programs") because
previously, CAP_SYS_ADMIN was required to reach the vulnerable code.
(posted publicly according to request by maintainer)
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-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: Chatur27 <jasonbright2709@gmail.com>
Diffstat (limited to 'kernel/bpf/stackmap.c')
0 files changed, 0 insertions, 0 deletions