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| author | Li Zefan <lizefan@huawei.com> | 2013-05-09 15:08:15 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-19 11:38:21 -0700 |
| commit | 159590f26d8658d627fee5841ffbe8ac0670031d (patch) | |
| tree | 3d314efcaee8a5b9b9105c62e4c06bab0ad57da4 /mm | |
| parent | 7b44587e0383980f76da1569249ec8fa662b9411 (diff) | |
| download | lwn-159590f26d8658d627fee5841ffbe8ac0670031d.tar.gz lwn-159590f26d8658d627fee5841ffbe8ac0670031d.zip | |
shm: fix null pointer deref when userspace specifies invalid hugepage size
commit 091d0d55b286c9340201b4ed4470be87fc568228 upstream.
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>
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mmap.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index e17fc067bd05..0dceed852b5c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1331,9 +1331,13 @@ 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 |