libext2fs: check for invalid blocks in ext2fs_punch_blocks()

If the extent tree has out-of-range physical block numbers, don't try
to release them.

Also add a similar check in ext2fs_block_alloc_stats2() to avoid a
NULL pointer dereference.

Reported-by: Nils Bars <nils.bars@rub.de>
Reported-by: Moritz Schlögel <moritz.schloegel@rub.de>
Reported-by: Nico Schiller <nico.schiller@rub.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/lib/ext2fs/alloc_stats.c b/lib/ext2fs/alloc_stats.c
index 3949f61..6f98bcc 100644 (file)
--- a/lib/ext2fs/alloc_stats.c
+++ b/lib/ext2fs/alloc_stats.c
@@ -62,7 +62,8 @@ void ext2fs_block_alloc_stats2(ext2_filsys fs, blk64_t blk, int inuse)
 {
        int     group = ext2fs_group_of_blk2(fs, blk);
 
-       if (blk >= ext2fs_blocks_count(fs->super)) {
+       if (blk < fs->super->s_first_data_block ||
+           blk >= ext2fs_blocks_count(fs->super)) {
 #ifndef OMIT_COM_ERR
                com_err("ext2fs_block_alloc_stats", 0,
                        "Illegal block number: %lu", (unsigned long) blk);

diff --git a/lib/ext2fs/punch.c b/lib/ext2fs/punch.c
index effa1e2..e2543e1 100644 (file)
--- a/lib/ext2fs/punch.c
+++ b/lib/ext2fs/punch.c
@@ -200,6 +200,10 @@ static errcode_t punch_extent_blocks(ext2_filsys fs, ext2_ino_t ino,
        __u32           cluster_freed;
        errcode_t       retval = 0;
 
+       if (free_start < fs->super->s_first_data_block ||
+           (free_start + free_count) >= ext2fs_blocks_count(fs->super))
+               return EXT2_ET_BAD_BLOCK_NUM;
+
        /* No bigalloc?  Just free each block. */
        if (EXT2FS_CLUSTER_RATIO(fs) == 1) {
                *freed += free_count;