diff options
| author | Paul Emge <paulemge@forallsecure.com> | 2019-07-08 16:37:06 -0700 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2019-07-18 11:31:29 -0400 |
| commit | 084be43b751df7133c94c6bf556bc61bd6297406 (patch) | |
| tree | 2442cc233bbd36176591013b8143b75b2cf82915 /fs/ext4 | |
| parent | 878269dbe74229005dd7f27aca66c554e31dad8e (diff) | |
ext4: gracefully fail on divide-by-0
This patch checks for 0 in several ext4 headers and gracefully
fails instead of raising a divide-by-0 exception.
Signed-off-by: Paul Emge <paulemge@forallsecure.com>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/ext4_common.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c index 8a142e2e6a..5bf78b530a 100644 --- a/fs/ext4/ext4_common.c +++ b/fs/ext4/ext4_common.c @@ -1571,8 +1571,12 @@ static int ext4fs_blockgroup int log2blksz = get_fs()->dev_desc->log2blksz; int desc_size = get_fs()->gdsize; + if (desc_size == 0) + return 0; desc_per_blk = EXT2_BLOCK_SIZE(data) / desc_size; + if (desc_per_blk == 0) + return 0; blkno = le32_to_cpu(data->sblock.first_data_block) + 1 + group / desc_per_blk; blkoff = (group % desc_per_blk) * desc_size; @@ -1602,6 +1606,10 @@ int ext4fs_read_inode(struct ext2_data *data, int ino, struct ext2_inode *inode) /* It is easier to calculate if the first inode is 0. */ ino--; + if ( le32_to_cpu(sblock->inodes_per_group) == 0 || fs->inodesz == 0) { + free(blkgrp); + return 0; + } status = ext4fs_blockgroup(data, ino / le32_to_cpu (sblock->inodes_per_group), blkgrp); if (status == 0) { @@ -1610,6 +1618,10 @@ int ext4fs_read_inode(struct ext2_data *data, int ino, struct ext2_inode *inode) } inodes_per_block = EXT2_BLOCK_SIZE(data) / fs->inodesz; + if ( inodes_per_block == 0 ) { + free(blkgrp); + return 0; + } blkno = ext4fs_bg_get_inode_table_id(blkgrp, fs) + (ino % le32_to_cpu(sblock->inodes_per_group)) / inodes_per_block; blkoff = (ino % inodes_per_block) * fs->inodesz; |