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authorLi Zefan <lizefan@huawei.com>2013-05-09 15:08:15 +0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-09 14:22:47 -0700
commit091d0d55b286c9340201b4ed4470be87fc568228 (patch)
tree5417ab8864fbabe1a9931f3a9a81355cd3d3ebaa /ipc
parentde2657f94acd4f0df44626db7c4d2b71babc8cd3 (diff)
downloadlinaro-lsk-091d0d55b286c9340201b4ed4470be87fc568228.tar.gz
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>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/shm.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index 34af1fe3470..7e199fa1960 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -493,7 +493,13 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
if (shmflg & SHM_HUGETLB) {
struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
& SHM_HUGE_MASK);
- size_t hugesize = ALIGN(size, huge_page_size(hs));
+ size_t hugesize;
+
+ if (!hs) {
+ error = -EINVAL;
+ goto no_file;
+ }
+ hugesize = ALIGN(size, huge_page_size(hs));
/* hugetlb_file_setup applies strict accounting */
if (shmflg & SHM_NORESERVE)