ext4: avoid stamping on other memories in ext4_ext_insert_index()

Add a sanity check to make sure ix hasn't gone beyond the valid bounds of the extent block. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
git-mirror · Oct 17, 2011 · f472e02 · f472e02
1 parent d44651d
commit f472e02
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
@@ -779,6 +779,11 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 		ix = curp->p_idx;
 	}
 
+	if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
+		EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
+		return -EIO;
+	}
+
 	ix->ei_block = cpu_to_le32(logical);
 	ext4_idx_store_pblock(ix, ptr);
 	le16_add_cpu(&curp->p_hdr->eh_entries, 1);