From 275c0a8f1253a7542ad9726956c918d8a1f694c4 Mon Sep 17 00:00:00 2001 From: Duane Griffin Date: Fri, 25 Jul 2008 01:46:31 -0700 Subject: [PATCH] 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext3/namei.c | 22 ++++++++++++---------- 1 file 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, 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<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 */ -- 2.20.1