wifi: mac80211: Replace strlcpy with strscpy

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().

Direct replacement is safe here since LOCAL_ASSIGN is only used by
TRACE macros and the return values are ignored.

[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@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230613003404.3538524-1-azeemshaikh38@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index e5edf6f..b8c53b4 100644 (file)
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -17,7 +17,7 @@
 
 #define MAXNAME                32
 #define LOCAL_ENTRY    __array(char, wiphy_name, 32)
-#define LOCAL_ASSIGN   strlcpy(__entry->wiphy_name, wiphy_name(local->hw.wiphy), MAXNAME)
+#define LOCAL_ASSIGN   strscpy(__entry->wiphy_name, wiphy_name(local->hw.wiphy), MAXNAME)
 #define LOCAL_PR_FMT   "%s"
 #define LOCAL_PR_ARG   __entry->wiphy_name