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[6/7] wifi: cfg80211: Annotate struct cfg80211_scan_request with __counted_by

Message ID 20230817211531.4193219-6-keescook@chromium.org (mailing list archive)
State Accepted
Delegated to: Johannes Berg
Headers show
Series wifi: cfg80211: Annotate with __counted_by | expand

Commit Message

Kees Cook Aug. 17, 2023, 9:15 p.m. UTC
Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct cfg80211_scan_request.
Additionally, since the element count member must be set before accessing
the annotated flexible array member, move its initialization earlier.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/net/cfg80211.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Gustavo A. R. Silva Aug. 17, 2023, 9:24 p.m. UTC | #1
On 8/17/23 15:15, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct cfg80211_scan_request.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Johannes Berg <johannes@sipsolutions.net>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: linux-wireless@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
--
Gustavo

> ---
>   include/net/cfg80211.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
> index 6efe216c01d2..a2afc94a5408 100644
> --- a/include/net/cfg80211.h
> +++ b/include/net/cfg80211.h
> @@ -2544,7 +2544,7 @@ struct cfg80211_scan_request {
>   	struct cfg80211_scan_6ghz_params *scan_6ghz_params;
>   
>   	/* keep last */
> -	struct ieee80211_channel *channels[];
> +	struct ieee80211_channel *channels[] __counted_by(n_channels);
>   };
>   
>   static inline void get_random_mask_addr(u8 *buf, const u8 *addr, const u8 *mask)
Jeff Johnson Aug. 17, 2023, 10:03 p.m. UTC | #2
On 8/17/2023 2:15 PM, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
> (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct cfg80211_scan_request.
> Additionally, since the element count member must be set before accessing
> the annotated flexible array member, move its initialization earlier.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Johannes Berg <johannes@sipsolutions.net>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: linux-wireless@vger.kernel.org
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Jeff Johnson <quic_jjohnson@quicinc.com>
diff mbox series

Patch

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 6efe216c01d2..a2afc94a5408 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -2544,7 +2544,7 @@  struct cfg80211_scan_request {
 	struct cfg80211_scan_6ghz_params *scan_6ghz_params;
 
 	/* keep last */
-	struct ieee80211_channel *channels[];
+	struct ieee80211_channel *channels[] __counted_by(n_channels);
 };
 
 static inline void get_random_mask_addr(u8 *buf, const u8 *addr, const u8 *mask)