diff mbox series

[net-next,2/9] netfilter: nf_tables: replace deprecated strncpy with strscpy_pad

Message ID 20241014111420.29127-3-pablo@netfilter.org (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series [net-next,1/9] netfilter: nf_tables: Fix percpu address space issues in nf_tables_api.c | expand

Checks

Context Check Description
netdev/series_format success Pull request is its own cover letter
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 5 maintainers not CCed: razor@blackwall.org coreteam@netfilter.org bridge@lists.linux.dev kadlec@netfilter.org roopa@nvidia.com
netdev/build_clang success Errors and warnings before: 3 this patch: 3
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest fail net-next-2024-10-14--15-00 (tests: 775)

Commit Message

Pablo Neira Ayuso Oct. 14, 2024, 11:14 a.m. UTC 
From: Justin Stitt <justinstitt@google.com>

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@chromium.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/bridge/netfilter/nft_meta_bridge.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

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;