Commit 5f536ac6 authored by Kees Cook's avatar Kees Cook
Browse files

LoadPin: Annotate struct dm_verity_loadpin_trusted_root_digest 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 dm_verity_loadpin_trusted_root_digest.
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: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: dm-devel@redhat.com
Cc: Paul Moore <paul@paul-moore.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module@vger.kernel.org
Link: https://lore.kernel.org/r/20230817235955.never.762-kees@kernel.org


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 76903a96

include/linux/dm-verity-loadpin.h

+1 −1
Original line number Diff line number Diff line
@@ -12,7 +12,7 @@ extern struct list_head dm_verity_loadpin_trusted_root_digests; 
struct dm_verity_loadpin_trusted_root_digest {

	struct list_head node;

	unsigned int len;

	u8 data[];

	u8 data[] __counted_by(len);

};



#if IS_ENABLED(CONFIG_SECURITY_LOADPIN_VERITY)

security/loadpin/loadpin.c

+1 −2
Original line number Diff line number Diff line
@@ -336,6 +336,7 @@ static int read_trusted_verity_root_digests(unsigned int fd) 
			rc = -ENOMEM;

			goto err;

		}

		trd->len = len;



		if (hex2bin(trd->data, d, len)) {

			kfree(trd);
@@ -343,8 +344,6 @@ static int read_trusted_verity_root_digests(unsigned int fd) 
			goto err;

		}



		trd->len = len;



		list_add_tail(&trd->node, &dm_verity_loadpin_trusted_root_digests);

	}