Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756804Ab3FCKAi (ORCPT ); Mon, 3 Jun 2013 06:00:38 -0400 Received: from mail-ea0-f174.google.com ([209.85.215.174]:45505 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752516Ab3FCKA0 (ORCPT ); Mon, 3 Jun 2013 06:00:26 -0400 From: Ruslan Bilovol To: tytso@mit.edu, adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] ext4: add sanity checks in __ext4_check_dir_entry Date: Mon, 3 Jun 2013 13:00:16 +0300 Message-Id: <1370253616-8173-3-git-send-email-ruslan.bilovol@ti.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1370253616-8173-1-git-send-email-ruslan.bilovol@ti.com> References: <1370253616-8173-1-git-send-email-ruslan.bilovol@ti.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2642 Lines: 60 Added checks for NULL before dereferencing some pointers This fixes next issue: [ 1531.530609] Unable to handle kernel NULL pointer dereference at virtual address 00000004 [ 1531.543151] pgd = d6068000 [ 1531.546112] [00000004] *pgd=00000000 [ 1531.550109] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 1531.555816] Modules linked in: rproc_drm(O) tf_driver(O) gps_drv wl18xx(O) wl12xx(O) wlcore(O) mac80211(O) cfg80211(O) pvrsrvkm_sgx540_120(O) compat(O) [ 1531.571105] CPU: 0 Tainted: G W O (3.4.34 #1) [ 1531.576934] PC is at __ext4_check_dir_entry+0x24/0x1a4 [ 1531.582550] LR is at ext4_readdir+0x270/0x7fc [ 1531.587249] pc : [] lr : [] psr: 80000113 [ 1531.587249] sp : d6051e50 ip : 00000000 fp : d6051eb4 [ 1531.599700] r10: d4f0fdb0 r9 : c06a5c54 r8 : 000000d5 [ 1531.605377] r7 : d4c54540 r6 : d4634948 r5 : 00000000 r4 : 00000000 [ 1531.612396] r3 : d4634948 r2 : d4f0fdb0 r1 : 000000d5 r0 : c06a5c54 [ 1531.619476] Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 1531.627166] Control: 10c5387d Table: 9606804a DAC: 00000015 [...] [ 1532.654876] Backtrace: [ 1532.657653] [] (__ext4_check_dir_entry+0x0/0x1a4) from [] (ext4_readdir+0x270/0x7fc) [ 1532.667968] [] (ext4_readdir+0x0/0x7fc) from [] (vfs_readdir+0x9c/0xc0) [ 1532.677062] [] (vfs_readdir+0x0/0xc0) from [] (sys_getdents64+0x68/0xc0) [ 1532.686248] [] (sys_getdents64+0x0/0xc0) from [] (ret_fast_syscall+0x0/0x30) [ 1532.695800] r7:000000d9 r6:00000000 r5:416d4168 r4:416d4158 [ 1532.702270] Code: e1a07003 e1a09000 e1a08001 e59b3008 (e1dc40b4) Signed-off-by: Ruslan Bilovol --- fs/ext4/dir.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index f8d56e4..cf0875b 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -68,8 +68,12 @@ int __ext4_check_dir_entry(const char *function, unsigned int line, unsigned int offset) { const char *error_msg = NULL; - const int rlen = ext4_rec_len_from_disk(de->rec_len, - dir->i_sb->s_blocksize); + int rlen; + + if (!de || !bh || !dir) + return 1; + + rlen = ext4_rec_len_from_disk(de->rec_len, dir->i_sb->s_blocksize); if (unlikely(rlen < EXT4_DIR_REC_LEN(1))) error_msg = "rec_len is smaller than minimal"; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/