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| author | Li Zefan <lizefan@huawei.com> | 2013-05-09 15:08:15 +0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-05-09 14:22:47 -0700 |
| commit | 091d0d55b286c9340201b4ed4470be87fc568228 (patch) | |
| tree | 5417ab8864fbabe1a9931f3a9a81355cd3d3ebaa | |
| parent | de2657f94acd4f0df44626db7c4d2b71babc8cd3 (diff) | |
| download | linux-exynos-091d0d55b286c9340201b4ed4470be87fc568228.tar.gz linux-exynos-091d0d55b286c9340201b4ed4470be87fc568228.tar.bz2 linux-exynos-091d0d55b286c9340201b4ed4470be87fc568228.zip | |
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.c | 8 | ||||
| -rw-r--r-- | mm/mmap.c | 8 |
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) 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) 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, len = ALIGN(len, huge_page_size(hstate_file(file))); } else if (flags & MAP_HUGETLB) { struct user_struct *user = NULL; + struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & + SHM_HUGE_MASK); - len = ALIGN(len, huge_page_size(hstate_sizelog( - (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK))); + if (!hs) + return -EINVAL; + + len = ALIGN(len, huge_page_size(hs)); /* * VM_NORESERVE is used because the reservations will be * taken when vm_ops->mmap() is called |