From bb3b775d72abdf60a7ba1f93aadb1d53a32c778b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Sebasti=C3=A1n=20Alba=20Vives?= Date: Sun, 29 Mar 2026 07:11:11 +0000 Subject: [PATCH] staging: vc04_services: vchiq-mmal: validate component index in event_to_host_cb() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit event_to_host_cb() uses msg->u.event_to_host.client_component as an index into the instance->component[] array (size VCHIQ_MMAL_MAX_COMPONENTS = 64) without bounds validation. While the kernel generally trusts the hardware it is bound to, a bounds check here hardens the driver against potential firmware bugs that could otherwise cause an uncontrolled out-of-bounds array access and kernel crash. Add a bounds check on comp_idx before using it as an array index and move the component pointer assignment after the validation. Use pr_err_ratelimited() to avoid log flooding. Note: this file does not currently have access to a struct device, so dev_err() is not available. Cc: stable@vger.kernel.org Fixes: b18ee53ad297 ("staging: bcm2835: Break MMAL support out from camera") Signed-off-by: Sebastián Alba Vives --- drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c index 190d4808ffd90..ec42af0ed45a0 100644 --- a/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c +++ b/drivers/staging/vc04_services/vchiq-mmal/mmal-vchiq.c @@ -478,12 +478,19 @@ static void event_to_host_cb(struct vchiq_mmal_instance *instance, struct mmal_msg *msg, u32 msg_len) { int comp_idx = msg->u.event_to_host.client_component; - struct vchiq_mmal_component *component = - &instance->component[comp_idx]; + struct vchiq_mmal_component *component; struct vchiq_mmal_port *port = NULL; struct mmal_msg_context *msg_context; u32 port_num = msg->u.event_to_host.port_num; + if (comp_idx < 0 || comp_idx >= VCHIQ_MMAL_MAX_COMPONENTS) { + pr_err_ratelimited("%s: component index %d out of range\n", + __func__, comp_idx); + return; + } + + component = &instance->component[comp_idx]; + if (msg->u.buffer_from_host.drvbuf.magic == MMAL_MAGIC) { pr_err("%s: MMAL_MSG_TYPE_BUFFER_TO_HOST with bad magic\n", __func__);