From: Justin Stitt <justinstitt@xxxxxxxxxx> strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. In this particular instance, the usage of strncpy() is fine and works as expected. However, towards the goal of [2], we should consider replacing it with an alternative as many instances of strncpy() are bug-prone. Its removal from the kernel promotes better long term health for the codebase. The current usage of strncpy() likely just wants the NUL-padding behavior offered by strncpy() and doesn't care about the NUL-termination. Since the compiler doesn't know the size of @dest, we can't use strtomem_pad(). Instead, use strscpy_pad() which behaves functionally the same as strncpy() in this context -- as we expect br_dev->name to be NUL-terminated itself. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 [2] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: linux-hardening@xxxxxxxxxxxxxxx Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> Reviewed-by: Simon Horman <horms@xxxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> --- net/bridge/netfilter/nft_meta_bridge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bridge/netfilter/nft_meta_bridge.c b/net/bridge/netfilter/nft_meta_bridge.c index d12a221366d6..5adced1e7d0c 100644 --- a/net/bridge/netfilter/nft_meta_bridge.c +++ b/net/bridge/netfilter/nft_meta_bridge.c @@ -63,7 +63,7 @@ static void nft_meta_bridge_get_eval(const struct nft_expr *expr, return nft_meta_get_eval(expr, regs, pkt); } - strncpy((char *)dest, br_dev ? br_dev->name : "", IFNAMSIZ); + strscpy_pad((char *)dest, br_dev ? br_dev->name : "", IFNAMSIZ); return; err: regs->verdict.code = NFT_BREAK; -- 2.30.2
