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@xxxxxxxxx> --- v1 -> v2: replace strncpy() with strscpy() instead of strscpy_pad() kernel/bpf/helpers.c | 9 ++------- 1 file 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); -- 2.35.1
