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[v2] wifi: ath10k: replace deprecated strncpy with memcpy

Message ID 20231024-strncpy-drivers-net-wireless-ath-ath10k-mac-c-v2-1-4c1f4cd4b4df@google.com
State New
Headers show
Series [v2] wifi: ath10k: replace deprecated strncpy with memcpy | expand

Commit Message

Justin Stitt Oct. 24, 2023, 5:42 p.m. UTC
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. Make this explicit with __nonstring and use a plain old
memcpy.

This is also consistent with future copies into arvif->u.ap.ssid:

	if (changed & BSS_CHANGED_SSID &&
	    vif->type == NL80211_IFTYPE_AP) {
		arvif->u.ap.ssid_len = vif->cfg.ssid_len;
		if (vif->cfg.ssid_len)
			memcpy(arvif->u.ap.ssid, vif->cfg.ssid,
			       vif->cfg.ssid_len);
		arvif->u.ap.hidden_ssid = info->hidden_ssid;
	}

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@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Changes in v2:
- update subject to include wifi
- prefer memcpy() over strtomem() (thanks Kalle, Jeff)
- rebase onto 6.6-rc7 @d88520ad73b79e71
- Link to v1: https://lore.kernel.org/r/20231013-strncpy-drivers-net-wireless-ath-ath10k-mac-c-v1-1-24e40201afa3@google.com
---
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(-)


---
base-commit: d88520ad73b79e71e3ddf08de335b8520ae41c5c
change-id: 20231013-strncpy-drivers-net-wireless-ath-ath10k-mac-c-c73a55666e6a

Best regards,
--
Justin Stitt <justinstitt@google.com>

Comments

Kalle Valo Oct. 31, 2023, 7:46 a.m. UTC | #1
Justin Stitt <justinstitt@google.com> wrote:

> 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. Make this explicit with __nonstring and use a plain old
> memcpy.
> 
> This is also consistent with future copies into arvif->u.ap.ssid:
> 
>         if (changed & BSS_CHANGED_SSID &&
>             vif->type == NL80211_IFTYPE_AP) {
>                 arvif->u.ap.ssid_len = vif->cfg.ssid_len;
>                 if (vif->cfg.ssid_len)
>                         memcpy(arvif->u.ap.ssid, vif->cfg.ssid,
>                                vif->cfg.ssid_len);
>                 arvif->u.ap.hidden_ssid = info->hidden_ssid;
>         }
> 
> 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@vger.kernel.org
> Signed-off-by: Justin Stitt <justinstitt@google.com>
> Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

Patch applied to ath-next branch of ath.git, thanks.

ac2f43d3d34e wifi: ath10k: replace deprecated strncpy with memcpy
diff mbox series

Patch

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..f3f6deb354c6 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -6125,9 +6125,8 @@  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));
 			arvif->u.ap.ssid_len = 4;
+			memcpy(arvif->u.ap.ssid, "mesh", arvif->u.ap.ssid_len);
 		}
 	}