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[198.0.35.241]) by smtp.gmail.com with ESMTPSA id v13-20020a63b64d000000b0057783b0f102sm3053318pgt.40.2023.09.22.10.49.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 10:49:53 -0700 (PDT) From: Kees Cook To: Mauro Carvalho Chehab Cc: Kees Cook , Hans Verkuil , lijian , linux-media@vger.kernel.org, Nathan Chancellor , Nick Desaulniers , Tom Rix , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, linux-hardening@vger.kernel.org Subject: [PATCH] media: v4l2-event: Annotate struct v4l2_subscribed_event with __counted_by Date: Fri, 22 Sep 2023 10:49:52 -0700 Message-Id: <20230922174951.work.160-kees@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2092; i=keescook@chromium.org; h=from:subject:message-id; bh=C66/icBEq2MG+m/4ZluAAHZC3P5Kpbkm+mwqC112tHk=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBlDdPAkSq5hJos3sXunT3ysggynSqRlnNPBwz8S uw47BLY+beJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZQ3TwAAKCRCJcvTf3G3A JrwJD/9Ga6dhlY0NaypMA6bx76My1z2ArqeY+4D5HEL3TANx74Wr4Kc0p/+suRYVJWhO2AcnxeU 2hrfzl3pi0Vvw9c5dSxjhNykeazY/+6bWYyMMPEZs+nkNWTNsSaNGWSuQlwi/DWkvux/s2CAfma aNW56Oa/XhHaEk7LI2ZSJilEjfkWfZ7Yak8Ud4M2+BCIntq+ML2oE8ms1fCZqoYjtvZ+/UsHTmS g3SYTUAf7cjUXhU15YO3y8zQyNYyZsatTU3HGJNpJAJjL/QYtBELDxXf70bmNHzha8SDMSv1YS8 MgDAkfMLfM7r+R4anEuiL/mXkrtSd6LB6jsKoXgK+VLjG1JP+UUKDIuvcmO7TM1l6VuHWj9WRld yTTwN4mMvPSm47Xx3PUaC6LuTijjcqhA3Ua6nFbW0zvaPg7IpV44SycHiEpioj88TrElu81AFrL kIGefhO0Hpe32pz7zFpcstbvnlZgAvxX88/pxkNiwIBzunAJ48TCSevzWX1fGf3Zt4iDpLr+bT5 V4BjtZntEnOCExVsQWu5ZfbI41epwpEP3p6WJ6KEcVIEcAzKw4q3Hbb0xAxEj0AR75RIOyyofOf 5wYS6DC88fkx+lu3Yu29SH5YEGxqz8hysn6mgDV1W4BcnwHl9dkjhIvY13uFHiexjRTItbx3DEf DL1oEuc RlCqUUwQ== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 v4l2_subscribed_event. 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: Mauro Carvalho Chehab Cc: Hans Verkuil Cc: lijian Cc: linux-media@vger.kernel.org Signed-off-by: Kees Cook --- drivers/media/v4l2-core/v4l2-event.c | 2 +- include/media/v4l2-event.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c index c5ce9f11ad7b..3898ff7edddb 100644 --- a/drivers/media/v4l2-core/v4l2-event.c +++ b/drivers/media/v4l2-core/v4l2-event.c @@ -238,6 +238,7 @@ int v4l2_event_subscribe(struct v4l2_fh *fh, sev = kvzalloc(struct_size(sev, events, elems), GFP_KERNEL); if (!sev) return -ENOMEM; + sev->elems = elems; for (i = 0; i < elems; i++) sev->events[i].sev = sev; sev->type = sub->type; @@ -245,7 +246,6 @@ int v4l2_event_subscribe(struct v4l2_fh *fh, sev->flags = sub->flags; sev->fh = fh; sev->ops = ops; - sev->elems = elems; mutex_lock(&fh->subscribe_lock); diff --git a/include/media/v4l2-event.h b/include/media/v4l2-event.h index 4ffa914ade3a..3a0e2588361c 100644 --- a/include/media/v4l2-event.h +++ b/include/media/v4l2-event.h @@ -78,7 +78,7 @@ struct v4l2_subscribed_event { unsigned int elems; unsigned int first; unsigned int in_use; - struct v4l2_kevent events[]; + struct v4l2_kevent events[] __counted_by(elems); }; /**