Commit 451a2886 authored by Al Viro's avatar Al Viro

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 8f7e885a
...@@ -1744,6 +1744,9 @@ sg_start_req(Sg_request *srp, unsigned char *cmd) ...@@ -1744,6 +1744,9 @@ sg_start_req(Sg_request *srp, unsigned char *cmd)
md->from_user = 0; md->from_user = 0;
} }
if (unlikely(iov_count > MAX_UIOVEC))
return -EINVAL;
if (iov_count) { if (iov_count) {
int size = sizeof(struct iovec) * iov_count; int size = sizeof(struct iovec) * iov_count;
struct iovec *iov; struct iovec *iov;
......
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