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net/packet: Annotate struct packet_fanout with __counted_by

PATCH Applied Kees Cook 3 participants 3 messages Oct 3, 2023 – Oct 6, 2023

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Kees Cook

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#0 lore raw

PATCH 1/1 net/packet: Annotate struct packet_fanout with __counted_by

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 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 packet_fanout.

Cc "David S. Miller" <[email protected]>
Cc Eric Dumazet <[email protected]>
Cc Jakub Kicinski <[email protected]>
Cc Paolo Abeni <[email protected]>
Cc Willem de Bruijn <[email protected]>
Cc Anqi Shen <[email protected]>
Cc [email protected]
Link https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by Kees Cook <[email protected]>
---
 net/packet/internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
net/packet/internal.h +1 -1
index 63f4865202c1..d29c94c45159 100644
@@ -94,7 +94,7 @@ struct packet_fanout {
 	spinlock_t		lock;
 	refcount_t		sk_ref;
 	struct packet_type	prot_hook ____cacheline_aligned_in_smp;
-	struct sock	__rcu	*arr[];
+	struct sock	__rcu	*arr[] __counted_by(max_num_members);
 };
 
 struct packet_rollover {
Signature · 1 line
2.34.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 8 lines · Kees Cook

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 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 packet_fanout.

Quoted 9 lines
Cc "David S. Miller" <[email protected]>
Cc Eric Dumazet <[email protected]>
Cc Jakub Kicinski <[email protected]>
Cc Paolo Abeni <[email protected]>
Cc Willem de Bruijn <[email protected]>
Cc Anqi Shen <[email protected]>
Cc [email protected]
Link https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by Kees Cook <[email protected]>
Reviewed-by Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

Quoted 17 lines
---
  net/packet/internal.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
net/packet/internal.h +1 -1
index 63f4865202c1..d29c94c45159 100644
@@ -94,7 +94,7 @@ struct packet_fanout {
  	spinlock_t		lock;
  	refcount_t		sk_ref;
  	struct packet_type	prot_hook ____cacheline_aligned_in_smp;
-	struct sock	__rcu	*arr[];
+	struct sock	__rcu	*arr[] __counted_by(max_num_members);
  };
 
  struct packet_rollover {
CI Applied
#2 lore raw
In reply to Kees Cook
This patch was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Hello:

This patch was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Quoted 9 lines · On Tue, 3 Oct 2023 16:17:41 -0700 you 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 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 packet_fanout.

[...]

Here is the summary with links:
- net/packet: Annotate struct packet_fanout with __counted_by

    https://git.kernel.org/netdev/net-next/c/b3783e5efde4

You are awesome, thank you!

Signature · 2 lines
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