[PATCH 4/5] rpmsg: validate incoming message length before propagating
From: Ohad Ben-Cohen <hidden>
Date: 2012-02-28 17:21:52
Also in:
linux-omap, lkml
Subsystem:
remote processor messaging (rpmsg) subsystem, the rest · Maintainers:
Bjorn Andersson, Mathieu Poirier, Linus Torvalds
When an inbound message arrives, validate its reported length before propagating it, otherwise buggy (or malicious) remote processors might trick us into accessing memory which we really shouldn't. Signed-off-by: Ohad Ben-Cohen <redacted> Cc: Grant Likely <redacted> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Mark Grosen <redacted> Cc: Suman Anna <redacted> Cc: Fernando Guzman Lugo <redacted> Cc: Rob Clark <redacted> Cc: Ludovic BARRE <redacted> Cc: Loic PALLARDY <redacted> Cc: Omar Ramirez Luna <redacted> --- drivers/rpmsg/virtio_rpmsg_bus.c | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index 4db9cf8..1e8b8b6 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c@@ -778,6 +778,16 @@ static void rpmsg_recv_done(struct virtqueue *rvq) print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1, msg, sizeof(*msg) + msg->len, true); + /* + * We currently use fixed-sized buffers, so trivially sanitize + * the reported payload length. + */ + if (len > RPMSG_BUF_SIZE || + msg->len > (len - sizeof(struct rpmsg_hdr))) { + dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len); + return; + } + /* use the dst addr to fetch the callback of the appropriate user */ mutex_lock(&vrp->endpoints_lock); ept = idr_find(&vrp->endpoints, msg->dst);
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1.7.5.4