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authorDmitry Monakhov <dmonakhov@openvz.org>2014-04-13 15:41:13 -0400
committerTheodore Ts'o <tytso@mit.edu>2014-04-13 15:41:13 -0400
commita18ed359bdddcded4f97ff5e2f07793ff9336913 (patch)
treee97441cbb56686a6d6b30cb562435f01ca6ddb8a /fs/ext4
parent8dc79ec4c0537e1b83c0739af82a7babefb30012 (diff)
ext4: always check ext4_ext_find_extent result
Where are some places where logic guaranties us that extent we are searching exits, but this may not be true due to on-disk data corruption. If such corruption happens we must prevent possible null pointer dereferences. Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/extents.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 38be06354b8..64b400356ca 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3313,6 +3313,11 @@ static int ext4_split_extent(handle_t *handle,
return PTR_ERR(path);
depth = ext_depth(inode);
ex = path[depth].p_ext;
+ if (!ex) {
+ EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
+ (unsigned long) map->m_lblk);
+ return -EIO;
+ }
uninitialized = ext4_ext_is_uninitialized(ex);
split_flag1 = 0;
@@ -3694,6 +3699,12 @@ static int ext4_convert_initialized_extents(handle_t *handle,
}
depth = ext_depth(inode);
ex = path[depth].p_ext;
+ if (!ex) {
+ EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
+ (unsigned long) map->m_lblk);
+ err = -EIO;
+ goto out;
+ }
}
err = ext4_ext_get_access(handle, inode, path + depth);
@@ -5340,6 +5351,12 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle,
return PTR_ERR(path);
depth = path->p_depth;
extent = path[depth].p_ext;
+ if (!extent) {
+ EXT4_ERROR_INODE(inode, "unexpected hole at %lu",
+ (unsigned long) start);
+ return -EIO;
+ }
+
current_block = le32_to_cpu(extent->ee_block);
if (start > current_block) {
/* Hole, move to the next extent */