aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLi Zefan <lizefan@huawei.com>2013-05-09 03:08:15 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-09 17:22:47 -0400
commit091d0d55b286c9340201b4ed4470be87fc568228 (patch)
tree5417ab8864fbabe1a9931f3a9a81355cd3d3ebaa
parentde2657f94acd4f0df44626db7c4d2b71babc8cd3 (diff)
shm: fix null pointer deref when userspace specifies invalid hugepage size
Dave reported an oops triggered by trinity: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: newseg+0x10d/0x390 PGD cf8c1067 PUD cf8c2067 PMD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC CPU: 2 PID: 7636 Comm: trinity-child2 Not tainted 3.9.0+#67 ... Call Trace: ipcget+0x182/0x380 SyS_shmget+0x5a/0x60 tracesys+0xdd/0xe2 This bug was introduced by commit af73e4d9506d ("hugetlbfs: fix mmap failure in unaligned size request"). Reported-by: Dave Jones <davej@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Li Zefan <lizfan@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--ipc/shm.c8
-rw-r--r--mm/mmap.c8
2 files changed, 13 insertions, 3 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index 34af1fe34701..7e199fa1960f 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -493,7 +493,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
493 if (shmflg & SHM_HUGETLB) { 493 if (shmflg & SHM_HUGETLB) {
494 struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) 494 struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
495 & SHM_HUGE_MASK); 495 & SHM_HUGE_MASK);
496 size_t hugesize = ALIGN(size, huge_page_size(hs)); 496 size_t hugesize;
497
498 if (!hs) {
499 error = -EINVAL;
500 goto no_file;
501 }
502 hugesize = ALIGN(size, huge_page_size(hs));
497 503
498 /* hugetlb_file_setup applies strict accounting */ 504 /* hugetlb_file_setup applies strict accounting */
499 if (shmflg & SHM_NORESERVE) 505 if (shmflg & SHM_NORESERVE)
diff --git a/mm/mmap.c b/mm/mmap.c
index 1ae21d645c68..f681e1842fad 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1367,9 +1367,13 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1367 len = ALIGN(len, huge_page_size(hstate_file(file))); 1367 len = ALIGN(len, huge_page_size(hstate_file(file)));
1368 } else if (flags & MAP_HUGETLB) { 1368 } else if (flags & MAP_HUGETLB) {
1369 struct user_struct *user = NULL; 1369 struct user_struct *user = NULL;
1370 struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) &
1371 SHM_HUGE_MASK);
1370 1372
1371 len = ALIGN(len, huge_page_size(hstate_sizelog( 1373 if (!hs)
1372 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))); 1374 return -EINVAL;
1375
1376 len = ALIGN(len, huge_page_size(hs));
1373 /* 1377 /*
1374 * VM_NORESERVE is used because the reservations will be 1378 * VM_NORESERVE is used because the reservations will be
1375 * taken when vm_ops->mmap() is called 1379 * taken when vm_ops->mmap() is called