@@ -91,6 +91,7 @@ struct ext4_extent_header {
};
#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
+#define EXT4_MAX_EXTENT_DEPTH 5
#define EXT4_EXTENT_TAIL_OFFSET(hdr) \
(sizeof(struct ext4_extent_header) + \
@@ -869,6 +869,12 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block,
eh = ext_inode_hdr(inode);
depth = ext_depth(inode);
+ if (depth < 0 || depth > EXT4_MAX_EXTENT_DEPTH) {
+ EXT4_ERROR_INODE(inode, "inode has invalid extent depth: %d",
+ depth);
+ ret = -EFSCORRUPTED;
+ goto err;
+ }
if (path) {
ext4_ext_drop_refs(path);
If there is a corupted file system where the claimed depth of the extent tree is -1, this can cause a massive buffer overrun leading to sadness. https://bugzilla.kernel.org/show_bug.cgi?id=199417 Signed-off-by: Theodore Ts'o <tytso@mit.edu> --- fs/ext4/ext4_extents.h | 1 + fs/ext4/extents.c | 6 ++++++ 2 files changed, 7 insertions(+)