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authorDuane Griffin <duaneg@dghda.com>2008-07-25 01:46:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:33 -0700
commit275c0a8f1253a7542ad9726956c918d8a1f694c4 (patch)
tree775834cb708749217f56523b9517aba700978409 /fs
parentcbe5f466f6995e10a10c7ae66d6dc8608f08a6b8 (diff)
downloadlinux-2.6.34-ux500-275c0a8f1253a7542ad9726956c918d8a1f694c4.tar.gz
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')
-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 d282ea87008..de13e919cd8 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,
de = (struct ext3_dir_entry_2 *) bh->b_data;
top = (struct ext3_dir_entry_2 *) ((char *) de + sb->s_blocksize -
EXT3_DIR_REC_LEN(0));
- for (; de < top; de = ext3_next_entry(de))
- if (ext3_match (namelen, name, de)) {
- if (!ext3_check_dir_entry("ext3_find_entry",
- dir, de, bh,
- (block<<EXT3_BLOCK_SIZE_BITS(sb))
- +((char *)de - bh->b_data))) {
- brelse (bh);
+ for (; de < top; de = ext3_next_entry(de)) {
+ int off = (block << EXT3_BLOCK_SIZE_BITS(sb))
+ + ((char *) de - bh->b_data);
+
+ if (!ext3_check_dir_entry(__func__, dir, de, bh, off)) {
+ brelse(bh);
*err = ERR_BAD_DX_DIR;
goto errout;
}
- *res_dir = de;
- dx_release (frames);
- return bh;
+
+ if (ext3_match(namelen, name, de)) {
+ *res_dir = de;
+ dx_release(frames);
+ return bh;
+ }
}
brelse (bh);
/* Check to see if we should continue to search */