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| author | Eric Sesterhenn <snakebyte@gmx.de> | 2008-10-16 07:04:10 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-16 20:21:46 +0200 |
| commit | 649f1ee6c705aab644035a7998d7b574193a598a (patch) | |
| tree | 81dcf2be969b90b8cda18c72229bb1ca71577749 /fs/hfsplus/bitmap.c | |
| parent | hfsplus: fix Buffer overflow with a corrupted image (diff) | |
| download | linux-649f1ee6c705aab644035a7998d7b574193a598a.tar.xz linux-649f1ee6c705aab644035a7998d7b574193a598a.zip | |
hfsplus: check read_mapping_page() return value
While testing more corrupted images with hfsplus, i came across
one which triggered the following bug:
[15840.675016] BUG: unable to handle kernel paging request at fffffffb
[15840.675016] IP: [<c0116a4f>] kmap+0x15/0x56
[15840.675016] *pde = 00008067 *pte = 00000000
[15840.675016] Oops: 0000 [#1] PREEMPT DEBUG_PAGEALLOC
[15840.675016] Modules linked in:
[15840.675016]
[15840.675016] Pid: 11575, comm: ln Not tainted (2.6.27-rc4-00123-gd3ee1b4-dirty #29)
[15840.675016] EIP: 0060:[<c0116a4f>] EFLAGS: 00010202 CPU: 0
[15840.675016] EIP is at kmap+0x15/0x56
[15840.675016] EAX: 00000246 EBX: fffffffb ECX: 00000000 EDX: cab919c0
[15840.675016] ESI: 000007dd EDI: cab0bcf4 EBP: cab0bc98 ESP: cab0bc94
[15840.675016] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
[15840.675016] Process ln (pid: 11575, ti=cab0b000 task=cab919c0 task.ti=cab0b000)
[15840.675016] Stack: 00000000 cab0bcdc c0231cfb 00000000 cab0bce0 00000800 ca9290c0 fffffffb
[15840.675016] cab145d0 cab919c0 cab15998 22222222 22222222 22222222 00000001 cab15960
[15840.675016] 000007dd cab0bcf4 cab0bd04 c022cb3a cab0bcf4 cab15a6c ca9290c0 00000000
[15840.675016] Call Trace:
[15840.675016] [<c0231cfb>] ? hfsplus_block_allocate+0x6f/0x2d3
[15840.675016] [<c022cb3a>] ? hfsplus_file_extend+0xc4/0x1db
[15840.675016] [<c022ce41>] ? hfsplus_get_block+0x8c/0x19d
[15840.675016] [<c06adde4>] ? sub_preempt_count+0x9d/0xab
[15840.675016] [<c019ece6>] ? __block_prepare_write+0x147/0x311
[15840.675016] [<c0161934>] ? __grab_cache_page+0x52/0x73
[15840.675016] [<c019ef4f>] ? block_write_begin+0x79/0xd5
[15840.675016] [<c022cdb5>] ? hfsplus_get_block+0x0/0x19d
[15840.675016] [<c019f22a>] ? cont_write_begin+0x27f/0x2af
[15840.675016] [<c022cdb5>] ? hfsplus_get_block+0x0/0x19d
[15840.675016] [<c0139ebe>] ? tick_program_event+0x28/0x4c
[15840.675016] [<c013bd35>] ? trace_hardirqs_off+0xb/0xd
[15840.675016] [<c022b723>] ? hfsplus_write_begin+0x2d/0x32
[15840.675016] [<c022cdb5>] ? hfsplus_get_block+0x0/0x19d
[15840.675016] [<c0161988>] ? pagecache_write_begin+0x33/0x107
[15840.675016] [<c01879e5>] ? __page_symlink+0x3c/0xae
[15840.675016] [<c019ad34>] ? __mark_inode_dirty+0x12f/0x137
[15840.675016] [<c0187a70>] ? page_symlink+0x19/0x1e
[15840.675016] [<c022e6eb>] ? hfsplus_symlink+0x41/0xa6
[15840.675016] [<c01886a9>] ? vfs_symlink+0x99/0x101
[15840.675016] [<c018a2f6>] ? sys_symlinkat+0x6b/0xad
[15840.675016] [<c018a348>] ? sys_symlink+0x10/0x12
[15840.675016] [<c01038bd>] ? sysenter_do_call+0x12/0x31
[15840.675016] =======================
[15840.675016] Code: 00 00 75 10 83 3d 88 2f ec c0 02 75 07 89 d0 e8 12 56 05 00 5d c3 55 ba 06 00 00 00 89 e5 53 89 c3 b8 3d eb 7e c0 e8 16 74 00 00 <8b> 03 c1 e8 1e 69 c0 d8 02 00 00 05 b8 69 8e c0 2b 80 c4 02 00
[15840.675016] EIP: [<c0116a4f>] kmap+0x15/0x56 SS:ESP 0068:cab0bc94
[15840.675016] ---[ end trace 4fea40dad6b70e5f ]---
This happens because the return value of read_mapping_page() is passed on
to kmap unchecked. The bug is triggered after the first
read_mapping_page() in hfsplus_block_allocate(), this patch fixes all
three usages in this functions but leaves the ones further down in the
file unchanged.
Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/hfsplus/bitmap.c')
| -rw-r--r-- | fs/hfsplus/bitmap.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/hfsplus/bitmap.c b/fs/hfsplus/bitmap.c index d128a25b74d2..ea30afc2a03c 100644 --- a/fs/hfsplus/bitmap.c +++ b/fs/hfsplus/bitmap.c @@ -32,6 +32,10 @@ int hfsplus_block_allocate(struct super_block *sb, u32 size, u32 offset, u32 *ma mutex_lock(&HFSPLUS_SB(sb).alloc_file->i_mutex); mapping = HFSPLUS_SB(sb).alloc_file->i_mapping; page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, NULL); + if (IS_ERR(page)) { + start = size; + goto out; + } pptr = kmap(page); curr = pptr + (offset & (PAGE_CACHE_BITS - 1)) / 32; i = offset % 32; @@ -73,6 +77,10 @@ int hfsplus_block_allocate(struct super_block *sb, u32 size, u32 offset, u32 *ma break; page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, NULL); + if (IS_ERR(page)) { + start = size; + goto out; + } curr = pptr = kmap(page); if ((size ^ offset) / PAGE_CACHE_BITS) end = pptr + PAGE_CACHE_BITS / 32; @@ -120,6 +128,10 @@ found: offset += PAGE_CACHE_BITS; page = read_mapping_page(mapping, offset / PAGE_CACHE_BITS, NULL); + if (IS_ERR(page)) { + start = size; + goto out; + } pptr = kmap(page); curr = pptr; end = pptr + PAGE_CACHE_BITS / 32; |