strncpy() is deprecated [1] and we should prefer less ambiguous interfaces. In this case, arvif->u.ap.ssid has its length maintained by arvif->u.ap.ssid_len which indicates it may not need to be NUL-terminated, although by virtue of using strtomem_pad (with NUL-byte pad character) and having a destination size larger than the source, ssid will, incidentally, be NUL-terminated here. As strtomem_pad() docs say: * @dest: Pointer of destination character array (marked as __nonstring) * @src: Pointer to NUL-terminated string * @pad: Padding character to fill any remaining bytes of @dest after copy * * This is a replacement for strncpy() uses where the destination is not * a NUL-terminated string, but with bounds checking on the source size, and * an explicit padding character. If padding is not required, use strtomem(). Let's also mark ath10k_vif.u.ap.ssid as __nonstring. It is unclear to me whether padding is strictly necessary. Perhaps we should opt for just strtomem() -- padding certainly doesn't hurt, though. 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 Cc: linux-hardening@xxxxxxxxxxxxxxx Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx> --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/wireless/ath/ath10k/core.h | 2 +- drivers/net/wireless/ath/ath10k/mac.c | 3 +-- 2 files changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h index 4b5239de4018..ba9795a8378a 100644 --- a/drivers/net/wireless/ath/ath10k/core.h +++ b/drivers/net/wireless/ath/ath10k/core.h @@ -607,7 +607,7 @@ struct ath10k_vif { u8 tim_bitmap[64]; u8 tim_len; u32 ssid_len; - u8 ssid[IEEE80211_MAX_SSID_LEN]; + u8 ssid[IEEE80211_MAX_SSID_LEN] __nonstring; bool hidden_ssid; /* P2P_IE with NoA attribute for P2P_GO case */ u32 noa_len; diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index 03e7bc5b6c0b..7daa007bd8b3 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -6125,8 +6125,7 @@ static void ath10k_bss_info_changed(struct ieee80211_hw *hw, if (ieee80211_vif_is_mesh(vif)) { /* mesh doesn't use SSID but firmware needs it */ - strncpy(arvif->u.ap.ssid, "mesh", - sizeof(arvif->u.ap.ssid)); + strtomem_pad(arvif->u.ap.ssid, "mesh", '\0'); arvif->u.ap.ssid_len = 4; } } --- base-commit: cbf3a2cb156a2c911d8f38d8247814b4c07f49a2 change-id: 20231013-strncpy-drivers-net-wireless-ath-ath10k-mac-c-c73a55666e6a Best regards, -- Justin Stitt <justinstitt@xxxxxxxxxx>
