Hi, These patches fix two issues reported[1] a while back by Joe and Andrea around how shmat(2) behaves with nil-page.
The first reverts a commit that it was incorrectly thought that mapping nil-page (address=0) was a no no with MAP_FIXED. This is not the case, with the exception of SHM_REMAP; which is address in the second patch. I chose two patches because it is easier to backport and it explicitly reverts bogus behaviour. Both patches ought to be in -stable and ltp testcases need updated (the added testcase around the cve can be modified to just test for SHM_RND|SHM_REMAP). [1] lkml.kernel.org/r/20180430172152.nfa564pvgpk3ut7p@linux-n805 Thanks! Davidlohr Bueso (2): Revert "ipc/shm: Fix shmat mmap nil-page protection" ipc/shm: fix shmat() nil address after round-down when remapping ipc/shm.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) -- 2.13.6
