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afs: Annotate struct afs_permits 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_permits.

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

Cc: David Howells <dhowells@redhat.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: linux-afs@lists.infradead.org
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230915201456.never.529-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook 2023-09-15 13:14:56 -07:00
parent 5234193ee2
commit aade15333c

View File

@ -705,7 +705,7 @@ struct afs_permits {
refcount_t usage;
unsigned short nr_permits; /* Number of records */
bool invalidated; /* Invalidated due to key change */
struct afs_permit permits[]; /* List of permits sorted by key pointer */
struct afs_permit permits[] __counted_by(nr_permits); /* List of permits sorted by key pointer */
};
/*