From 451a2886b6bf90e2fb378f7c46c655450fb96e81 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 21 Mar 2015 20:08:18 -0400 Subject: [PATCH] sg_start_req(): make sure that there's not too many elements in iovec unfortunately, allowing an arbitrary 16bit value means a possibility of overflow in the calculation of total number of pages in bio_map_user_iov() - we rely on there being no more than PAGE_SIZE members of sum in the first loop there. If that sum wraps around, we end up allocating too small array of pointers to pages and it's easy to overflow it in the second loop. X-Coverup: TINC (and there's no lumber cartel either) Cc: stable@vger.kernel.org # way, way back Signed-off-by: Al Viro --- drivers/scsi/sg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index d383f84869aa45..b5a4db88322360 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1744,6 +1744,9 @@ sg_start_req(Sg_request *srp, unsigned char *cmd) md->from_user = 0; } + if (unlikely(iov_count > MAX_UIOVEC)) + return -EINVAL; + if (iov_count) { int size = sizeof(struct iovec) * iov_count; struct iovec *iov;