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| author | Yuntao Wang <ytcoode@gmail.com> | 2022-03-04 15:04:08 +0800 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2022-03-07 22:04:33 -0800 |
| commit | 03b9c7fa3f15f51bcd07f3828c2a01311e7746c4 (patch) | |
| tree | 0c06340fc7c23e7edcaec27e902d871fd1183cc9 /kernel | |
| parent | 9c6e6a80ee741adf6cb3cfd8eef7d1554f91fceb (diff) | |
| download | linux-03b9c7fa3f15f51bcd07f3828c2a01311e7746c4.tar.gz linux-03b9c7fa3f15f51bcd07f3828c2a01311e7746c4.tar.bz2 linux-03b9c7fa3f15f51bcd07f3828c2a01311e7746c4.zip | |
bpf: Replace strncpy() with strscpy()
Using strncpy() on NUL-terminated strings is considered deprecated[1].
Moreover, if the length of 'task->comm' is less than the destination buffer
size, strncpy() will NUL-pad the destination buffer, which is a needless
performance penalty.
Replacing strncpy() with strscpy() fixes all these issues.
[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220304070408.233658-1-ytcoode@gmail.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/helpers.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index ae64110a98b5..315053ef6a75 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -225,13 +225,8 @@ BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size) if (unlikely(!task)) goto err_clear; - strncpy(buf, task->comm, size); - - /* Verifier guarantees that size > 0. For task->comm exceeding - * size, guarantee that buf is %NUL-terminated. Unconditionally - * done here to save the size test. - */ - buf[size - 1] = 0; + /* Verifier guarantees that size > 0 */ + strscpy(buf, task->comm, size); return 0; err_clear: memset(buf, 0, size); |