[PATCH] bpf: Replace all non-returning strlcpy with strscpy

From: Azeem Shaikh
Date: Tue May 30 2023 - 11:57:23 EST


strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@xxxxxxxxx>
---
kernel/bpf/preload/bpf_preload_kern.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/preload/bpf_preload_kern.c b/kernel/bpf/preload/bpf_preload_kern.c
index b56f9f3314fd..0c63bc2cd895 100644
--- a/kernel/bpf/preload/bpf_preload_kern.c
+++ b/kernel/bpf/preload/bpf_preload_kern.c
@@ -23,9 +23,9 @@ static void free_links_and_skel(void)

static int preload(struct bpf_preload_info *obj)
{
- strlcpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
+ strscpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
obj[0].link = maps_link;
- strlcpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
+ strscpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
obj[1].link = progs_link;
return 0;
}