| Message ID | 20220304070408.233658-1-ytcoode@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 03b9c7fa3f15f51bcd07f3828c2a01311e7746c4 |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next,v2] bpf: Replace strncpy() with strscpy() | expand |
| Context | Check | Description |
|---|---|---|
| bpf/vmtest-bpf-next-PR | success | PR summary |
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Single patches do not need cover letters |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 9 this patch: 9 |
| netdev/cc_maintainers | success | CCed 10 of 10 maintainers |
| netdev/build_clang | success | Errors and warnings before: 18 this patch: 18 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 14 this patch: 14 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 15 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
| bpf/vmtest-bpf-next | success | VM_Test |
On 3/3/22 11:04 PM, Yuntao Wang wrote: > 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> Acked-by: Yonghong Song <yhs@fb.com>
Hello: This patch was applied to bpf/bpf-next.git (master) by Andrii Nakryiko <andrii@kernel.org>: On Fri, 4 Mar 2022 15:04:08 +0800 you wrote: > 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. > > [...] Here is the summary with links: - [bpf-next,v2] bpf: Replace strncpy() with strscpy() https://git.kernel.org/bpf/bpf-next/c/03b9c7fa3f15 You are awesome, thank you!
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);
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> --- v1 -> v2: replace strncpy() with strscpy() instead of strscpy_pad() kernel/bpf/helpers.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)