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authorAl Viro <viro@zeniv.linux.org.uk>2015-03-21 20:08:18 -0400
committerJiri Slaby <jslaby@suse.cz>2015-08-04 16:52:37 +0200
commitaba300b9c26f063efcaee374e54264c79a611f22 (patch)
parent8c2552742bcbf034f25baf2a9417968aeeed1721 (diff)
sg_start_req(): make sure that there's not too many elements in iovec
commit 451a2886b6bf90e2fb378f7c46c655450fb96e81 upstream. 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. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> [bwh: s/MAX_UIOVEC/UIO_MAXIOV/. This was fixed upstream by commit fdc81f45e9f5 ("sg_start_req(): use import_iovec()"), but we don't have that function.] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index eb81c98386b9..721d839d6c54 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1694,6 +1694,9 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
md->from_user = 0;
+ if (unlikely(iov_count > UIO_MAXIOV))
+ return -EINVAL;
if (iov_count) {
int len, size = sizeof(struct sg_iovec) * iov_count;
struct iovec *iov;