diff options
| author | Cristian Marussi <cristian.marussi@arm.com> | 2022-12-22 18:38:20 +0000 |
|---|---|---|
| committer | Sudeep Holla <sudeep.holla@arm.com> | 2023-01-03 16:50:30 +0000 |
| commit | ad78b81a1077f7d956952cd8bdfe1e61504e3eb8 (patch) | |
| tree | d6cf40271b31f7f50ed876c4317a13df64f769cb /drivers/firmware | |
| parent | f6ca5059dc0d6608dc46070f48e396d611f240d6 (diff) | |
firmware: arm_scmi: Harden shared memory access in fetch_response
A misbheaving SCMI platform firmware could reply with out-of-spec messages,
shorter than the mimimum size comprising a header and a status field.
Harden shmem_fetch_response to properly truncate such a bad messages.
Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222183823.518856-3-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/arm_scmi/shmem.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index 1dfe534b8518..135f8718000f 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -81,10 +81,11 @@ u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem) void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, struct scmi_xfer *xfer) { + size_t len = ioread32(&shmem->length); + xfer->hdr.status = ioread32(shmem->msg_payload); /* Skip the length of header and status in shmem area i.e 8 bytes */ - xfer->rx.len = min_t(size_t, xfer->rx.len, - ioread32(&shmem->length) - 8); + xfer->rx.len = min_t(size_t, xfer->rx.len, len > 8 ? len - 8 : 0); /* Take a copy to the rx buffer.. */ memcpy_fromio(xfer->rx.buf, shmem->msg_payload + 4, xfer->rx.len); |