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authorAdrian Hunter <ext-adrian.hunter@nokia.com>2008-09-26 12:52:21 +0300
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2008-09-30 11:12:59 +0300
commitbe2f6bd62d0d4246a9227dacbe2469e1f0eccf26 (patch)
tree04ebddba4042ad0df7b5b03209ab42f555259ce0 /fs/ubifs/lpt_commit.c
parent63c300b68fd93a9fadc5e317d4d001b7a6985486 (diff)
downloadlinux-be2f6bd62d0d4246a9227dacbe2469e1f0eccf26.tar.bz2
UBIFS: check buffer length when scanning for LPT nodes
'is_a_node()' function was reading from a buffer before checking the buffer length, resulting in an OOPS as follows: BUG: unable to handle kernel paging request at f8f74002 IP: [<f8f9783f>] :ubifs:ubifs_unpack_bits+0xca/0x233 *pde = 19e95067 *pte = 00000000 Oops: 0000 [#1] PREEMPT SMP Modules linked in: ubifs ubi mtdchar bio2mtd mtd brd video output [last unloaded: mtd] Pid: 6414, comm: integck Not tainted (2.6.27-rc6ubifs34 #23) EIP: 0060:[<f8f9783f>] EFLAGS: 00010246 CPU: 0 EIP is at ubifs_unpack_bits+0xca/0x233 [ubifs] EAX: 00000000 EBX: f6090630 ECX: d9badcfc EDX: 00000000 ESI: 00000004 EDI: f8f74002 EBP: d9badcec ESP: d9badcc0 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 Process integck (pid: 6414, ti=d9bac000 task=f727dae0 task.ti=d9bac000) Stack: 00000006 f7306240 00000002 00000000 d9badcfc d9badd00 0000001c 00000000 f6090630 f6090630 f8f74000 d9badd10 f8fa1cc9 00000000 f8f74002 00000000 f8f74002 f60fe128 f6090630 f8f74000 d9badd68 f8fa1e46 00000000 0001e000 Call Trace: [<f8fa1cc9>] ? is_a_node+0x30/0x90 [ubifs] [<f8fa1e46>] ? dbg_check_ltab+0x11d/0x5bd [ubifs] [<f8fa388f>] ? ubifs_lpt_start_commit+0x42/0xed3 [ubifs] [<c038e76a>] ? mutex_unlock+0x8/0xa [<f8f9625d>] ? ubifs_tnc_start_commit+0x1c8/0xedb [ubifs] [<f8f8d90b>] ? do_commit+0x187/0x523 [ubifs] [<c038e76a>] ? mutex_unlock+0x8/0xa [<f8f7ca17>] ? bud_wbuf_callback+0x22/0x28 [ubifs] [<f8f8dd1d>] ? ubifs_run_commit+0x76/0xc0 [ubifs] [<f8f8032c>] ? ubifs_sync_fs+0xd2/0xe6 [ubifs] [<c01a2e97>] ? vfs_quota_sync+0x0/0x17e [<c01a5ba6>] ? quota_sync_sb+0x26/0xbb [<c01a2e97>] ? vfs_quota_sync+0x0/0x17e [<c01a5c5d>] ? sync_dquots+0x22/0x12c [<c0173d1b>] ? __fsync_super+0x19/0x68 [<c0173d75>] ? fsync_super+0xb/0x19 [<c0174065>] ? generic_shutdown_super+0x22/0xe7 [<c01a31fc>] ? vfs_quota_off+0x0/0x5fd [<f8f7cf4d>] ? ubifs_kill_sb+0x31/0x35 [ubifs] [<c01741f9>] ? deactivate_super+0x5e/0x71 [<c0187610>] ? mntput_no_expire+0x82/0xe4 [<c0187905>] ? sys_umount+0x4c/0x2f6 [<c0187bc8>] ? sys_oldumount+0x19/0x1b [<c0103b71>] ? sysenter_do_call+0x12/0x25 ======================= Code: c1 f8 03 8d 04 07 8b 4d e8 89 01 8b 45 e4 89 10 89 d8 89 f1 d3 e8 85 c0 74 07 29 d6 83 fe 20 75 2a 89 d8 83 c4 20 5b 5e 5f 5d EIP: [<f8f9783f>] ubifs_unpack_bits+0xca/0x233 [ubifs] SS:ESP 0068:d9badcc0 ---[ end trace 1f02572436518c13 ]--- Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Diffstat (limited to 'fs/ubifs/lpt_commit.c')
-rw-r--r--fs/ubifs/lpt_commit.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ubifs/lpt_commit.c b/fs/ubifs/lpt_commit.c
index 8546865a9104..eed5a0025d63 100644
--- a/fs/ubifs/lpt_commit.c
+++ b/fs/ubifs/lpt_commit.c
@@ -1089,6 +1089,8 @@ static int is_a_node(struct ubifs_info *c, uint8_t *buf, int len)
int pos = 0, node_type, node_len;
uint16_t crc, calc_crc;
+ if (len < UBIFS_LPT_CRC_BYTES + (UBIFS_LPT_TYPE_BITS + 7) / 8)
+ return 0;
node_type = ubifs_unpack_bits(&addr, &pos, UBIFS_LPT_TYPE_BITS);
if (node_type == UBIFS_LPT_NOT_A_NODE)
return 0;