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afs: Annotate struct afs_addr_list with __counted_by

PATCH Applied Kees Cook 2 participants 3 messages Sep 15, 2023 – Sep 29, 2023 Afs filesystem

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Kees Cook

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#0 lore raw

PATCH 1/1 afs: Annotate struct afs_addr_list 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 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 afs_addr_list.

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

Cc David Howells <[email protected]>
Cc Marc Dionne <[email protected]>
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
---
 fs/afs/internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
fs/afs/internal.h +1 -1
index da73b97e19a9..07433a5349ca 100644
@@ -87,7 +87,7 @@ struct afs_addr_list {
 	enum dns_lookup_status	status:8;
 	unsigned long		failed;		/* Mask of addrs that failed locally/ICMP */
 	unsigned long		responded;	/* Mask of addrs that responded */
-	struct sockaddr_rxrpc	addrs[];
+	struct sockaddr_rxrpc	addrs[] __counted_by(max_addrs);
 #define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
 };
Signature · 1 line
2.34.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 6 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 checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

Quoted 8 lines

As found with Coccinelle[1], add __counted_by for struct afs_addr_list.

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

Cc David Howells <[email protected]>
Cc Marc Dionne <[email protected]>
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
Reviewed-by Gustavo A. R. Silva <[email protected]>

Thanks

Signature · 1 line
Gustavo
Quoted 17 lines
---
  fs/afs/internal.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
fs/afs/internal.h +1 -1
index da73b97e19a9..07433a5349ca 100644
@@ -87,7 +87,7 @@ struct afs_addr_list {
  	enum dns_lookup_status	status:8;
  	unsigned long		failed;		/* Mask of addrs that failed locally/ICMP */
  	unsigned long		responded;	/* Mask of addrs that responded */
-	struct sockaddr_rxrpc	addrs[];
+	struct sockaddr_rxrpc	addrs[] __counted_by(max_addrs);
  #define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
  };
author Applied
#2 lore raw
In reply to Kees Cook
Quoted 9 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 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 afs_addr_list.

[...]

Applied to for-next/hardening, thanks!

[1/1] afs: Annotate struct afs_addr_list with __counted_by

      https://git.kernel.org/kees/c/7a709daf5d40

Take care,

Signature · 1 line
Kees Cook