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authorDuane Griffin <duaneg@dghda.com>2008-07-25 04:46:31 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 13:53:33 -0400
commit275c0a8f1253a7542ad9726956c918d8a1f694c4 (patch)
tree775834cb708749217f56523b9517aba700978409 /fs/ext3/namei.c
parentcbe5f466f6995e10a10c7ae66d6dc8608f08a6b8 (diff)
ext3: validate directory entry data before use
ext3_dx_find_entry uses ext3_next_entry without verifying that the entry is valid. If its rec_len == 0 this causes an infinite loop. Refactor the loop to check the validity of entries before checking whether they match and moving onto the next one. There are other uses of ext3_next_entry in this file which also look problematic. They should be reviewed and fixed if/when we have a test-case that triggers them. This patch fixes the first case (image hdb.25.softlockup.gz) reported in http://bugzilla.kernel.org/show_bug.cgi?id=10882. Signed-off-by: Duane Griffin <duaneg@dghda.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext3/namei.c')
-rw-r--r--fs/ext3/namei.c22
1 files changed, 12 insertions, 10 deletions
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index d282ea870081..de13e919cd81 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -991,19 +991,21 @@ static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry,
991 de = (struct ext3_dir_entry_2 *) bh->b_data; 991 de = (struct ext3_dir_entry_2 *) bh->b_data;
992 top = (struct ext3_dir_entry_2 *) ((char *) de + sb->s_blocksize - 992 top = (struct ext3_dir_entry_2 *) ((char *) de + sb->s_blocksize -
993 EXT3_DIR_REC_LEN(0)); 993 EXT3_DIR_REC_LEN(0));
994 for (; de < top; de = ext3_next_entry(de)) 994 for (; de < top; de = ext3_next_entry(de)) {
995 if (ext3_match (namelen, name, de)) { 995 int off = (block << EXT3_BLOCK_SIZE_BITS(sb))
996 if (!ext3_check_dir_entry("ext3_find_entry", 996 + ((char *) de - bh->b_data);
997 dir, de, bh, 997
998 (block<<EXT3_BLOCK_SIZE_BITS(sb)) 998 if (!ext3_check_dir_entry(__func__, dir, de, bh, off)) {
999 +((char *)de - bh->b_data))) { 999 brelse(bh);
1000 brelse (bh);
1001 *err = ERR_BAD_DX_DIR; 1000 *err = ERR_BAD_DX_DIR;
1002 goto errout; 1001 goto errout;
1003 } 1002 }
1004 *res_dir = de; 1003
1005 dx_release (frames); 1004 if (ext3_match(namelen, name, de)) {
1006 return bh; 1005 *res_dir = de;
1006 dx_release(frames);
1007 return bh;
1008 }
1007 } 1009 }
1008 brelse (bh); 1010 brelse (bh);
1009 /* Check to see if we should continue to search */ 1011 /* Check to see if we should continue to search */