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 xfrm_sec_ctx. Cc: Steffen Klassert <steffen.klass...@secunet.com> Cc: Herbert Xu <herb...@gondor.apana.org.au> Cc: "David S. Miller" <da...@davemloft.net> Cc: net...@vger.kernel.org Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1] Signed-off-by: Kees Cook <keesc...@chromium.org> --- include/uapi/linux/xfrm.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h index 23543c33fee8..6a77328be114 100644 --- a/include/uapi/linux/xfrm.h +++ b/include/uapi/linux/xfrm.h @@ -4,6 +4,7 @@ #include <linux/in6.h> #include <linux/types.h> +#include <linux/stddef.h> /* All of the structures in this file may not change size as they are * passed into the kernel from userspace via netlink sockets. @@ -33,7 +34,7 @@ struct xfrm_sec_ctx { __u8 ctx_alg; __u16 ctx_len; __u32 ctx_sid; - char ctx_str[]; + char ctx_str[] __counted_by(ctx_len); }; /* Security Context Domains of Interpretation */ -- 2.34.1
