aboutsummaryrefslogtreecommitdiff
path: root/drivers/rtc/rtc-stmp3xxx.c
diff options
context:
space:
mode:
authorKumar Kartikeya Dwivedi2021-10-28 12:04:57 +0530
committerAlexei Starovoitov2021-10-28 16:30:07 -0700
commit549a63238603103fa33cecd49487cf6c0f52e503 (patch)
treeb85e528f00cb0c7950487cbdbe58029356a617af /drivers/rtc/rtc-stmp3xxx.c
parent585a3571981d8a93e2211e1ac835d31a63e68cd8 (diff)
libbpf: Ensure that BPF syscall fds are never 0, 1, or 2
Add a simple wrapper for passing an fd and getting a new one >= 3 if it is one of 0, 1, or 2. There are two primary reasons to make this change: First, libbpf relies on the assumption a certain BPF fd is never 0 (e.g. most recently noticed in [0]). Second, Alexei pointed out in [1] that some environments reset stdin, stdout, and stderr if they notice an invalid fd at these numbers. To protect against both these cases, switch all internal BPF syscall wrappers in libbpf to always return an fd >= 3. We only need to modify the syscall wrappers and not other code that assumes a valid fd by doing >= 0, to avoid pointless churn, and because it is still a valid assumption. The cost paid is two additional syscalls if fd is in range [0, 2]. [0]: e31eec77e4ab ("bpf: selftests: Fix fd cleanup in get_branch_snapshot") [1]: https://lore.kernel.org/bpf/CAADnVQKVKY8o_3aU8Gzke443+uHa-eGoM0h7W4srChMXU1S4Bg@mail.gmail.com Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211028063501.2239335-5-memxor@gmail.com
Diffstat (limited to 'drivers/rtc/rtc-stmp3xxx.c')
0 files changed, 0 insertions, 0 deletions