sg_start_req(): make sure that there's not too many elements in iovec
authorAl Viro <viro@zeniv.linux.org.uk>
Sun, 22 Mar 2015 00:08:18 +0000 (20:08 -0400)
committerAl Viro <viro@zeniv.linux.org.uk>
Sun, 12 Apr 2015 02:27:13 +0000 (22:27 -0400)
commit451a2886b6bf90e2fb378f7c46c655450fb96e81
tree33dbcccb975a1943c7f015e54f0ce148f2bbc3d5
parent8f7e885a4cc167f8b1931800fa1319772ae4b11d
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>
drivers/scsi/sg.c