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authorTheodore Ts'o <tytso@mit.edu>2009-01-16 11:13:47 -0500
committerTheodore Ts'o <tytso@mit.edu>2009-01-16 11:13:47 -0500
commita21102b55c4f8dfd3adb4a15a34cd62237b46039 (patch)
tree270f663b46460ee6055073fe862b4ec68ee47bbd
parente6b8bc09ba2075cd91fbffefcd2778b1a00bd76f (diff)
ext3: Add sanity check to make_indexed_dir
Make sure the rec_len field in the '..' entry is sane, lest we overrun the directory block and cause a kernel oops on a purposefully corrupted filesystem. This fixes a bug related to a bug originally reported by Sami Liedes for ext4 at: http://bugzilla.kernel.org/show_bug.cgi?id=12430 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@kernel.org
-rw-r--r--fs/ext3/namei.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index 69a3d19ca9fd..4db4ffa1edad 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -1358,7 +1358,7 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1358 struct fake_dirent *fde; 1358 struct fake_dirent *fde;
1359 1359
1360 blocksize = dir->i_sb->s_blocksize; 1360 blocksize = dir->i_sb->s_blocksize;
1361 dxtrace(printk("Creating index\n")); 1361 dxtrace(printk(KERN_DEBUG "Creating index: inode %lu\n", dir->i_ino));
1362 retval = ext3_journal_get_write_access(handle, bh); 1362 retval = ext3_journal_get_write_access(handle, bh);
1363 if (retval) { 1363 if (retval) {
1364 ext3_std_error(dir->i_sb, retval); 1364 ext3_std_error(dir->i_sb, retval);
@@ -1367,6 +1367,19 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1367 } 1367 }
1368 root = (struct dx_root *) bh->b_data; 1368 root = (struct dx_root *) bh->b_data;
1369 1369
1370 /* The 0th block becomes the root, move the dirents out */
1371 fde = &root->dotdot;
1372 de = (struct ext3_dir_entry_2 *)((char *)fde +
1373 ext3_rec_len_from_disk(fde->rec_len));
1374 if ((char *) de >= (((char *) root) + blocksize)) {
1375 ext3_error(dir->i_sb, __func__,
1376 "invalid rec_len for '..' in inode %lu",
1377 dir->i_ino);
1378 brelse(bh);
1379 return -EIO;
1380 }
1381 len = ((char *) root) + blocksize - (char *) de;
1382
1370 bh2 = ext3_append (handle, dir, &block, &retval); 1383 bh2 = ext3_append (handle, dir, &block, &retval);
1371 if (!(bh2)) { 1384 if (!(bh2)) {
1372 brelse(bh); 1385 brelse(bh);
@@ -1375,11 +1388,6 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
1375 EXT3_I(dir)->i_flags |= EXT3_INDEX_FL; 1388 EXT3_I(dir)->i_flags |= EXT3_INDEX_FL;
1376 data1 = bh2->b_data; 1389 data1 = bh2->b_data;
1377 1390
1378 /* The 0th block becomes the root, move the dirents out */
1379 fde = &root->dotdot;
1380 de = (struct ext3_dir_entry_2 *)((char *)fde +
1381 ext3_rec_len_from_disk(fde->rec_len));
1382 len = ((char *) root) + blocksize - (char *) de;
1383 memcpy (data1, de, len); 1391 memcpy (data1, de, len);
1384 de = (struct ext3_dir_entry_2 *) data1; 1392 de = (struct ext3_dir_entry_2 *) data1;
1385 top = data1 + len; 1393 top = data1 + len;