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authorAl Viro <viro@zeniv.linux.org.uk>2015-03-21 20:08:18 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2015-04-11 22:27:13 -0400
commit451a2886b6bf90e2fb378f7c46c655450fb96e81 (patch)
tree33dbcccb975a1943c7f015e54f0ce148f2bbc3d5 /drivers/scsi
parent8f7e885a4cc167f8b1931800fa1319772ae4b11d (diff)
downloadlinux-451a2886b6bf90e2fb378f7c46c655450fb96e81.tar.gz
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 <viro@zeniv.linux.org.uk>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/sg.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index d383f84869aa..b5a4db883223 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;