omfs: check bounds on block numbers before passing to sb_bread
In case of filesystem corruption, passing unchecked block numbers into
sb_bread can result in an infinite loop in __getblk(). Introduce a wrapper
function omfs_sbread() to check the block numbers and to also perform the
clus_to_blk() scaling.
Signed-off-by: Bob Copeland <me@bobcopeland.com>
diff --git a/fs/omfs/inode.c b/fs/omfs/inode.c
index b5d6380..bd4bf75 100644
--- a/fs/omfs/inode.c
+++ b/fs/omfs/inode.c
@@ -19,6 +19,15 @@
MODULE_DESCRIPTION("OMFS (ReplayTV/Karma) Filesystem for Linux");
MODULE_LICENSE("GPL");
+struct buffer_head *omfs_bread(struct super_block *sb, sector_t block)
+{
+ struct omfs_sb_info *sbi = OMFS_SB(sb);
+ if (block >= sbi->s_num_blocks)
+ return NULL;
+
+ return sb_bread(sb, clus_to_blk(sbi, block));
+}
+
struct inode *omfs_new_inode(struct inode *dir, int mode)
{
struct inode *inode;
@@ -93,15 +102,13 @@
struct omfs_inode *oi;
struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
struct buffer_head *bh, *bh2;
- unsigned int block;
u64 ctime;
int i;
int ret = -EIO;
int sync_failed = 0;
/* get current inode since we may have written sibling ptrs etc. */
- block = clus_to_blk(sbi, inode->i_ino);
- bh = sb_bread(inode->i_sb, block);
+ bh = omfs_bread(inode->i_sb, inode->i_ino);
if (!bh)
goto out;
@@ -140,8 +147,7 @@
/* if mirroring writes, copy to next fsblock */
for (i = 1; i < sbi->s_mirrors; i++) {
- bh2 = sb_bread(inode->i_sb, block + i *
- (sbi->s_blocksize / sbi->s_sys_blocksize));
+ bh2 = omfs_bread(inode->i_sb, inode->i_ino + i);
if (!bh2)
goto out_brelse;
@@ -193,7 +199,6 @@
struct omfs_sb_info *sbi = OMFS_SB(sb);
struct omfs_inode *oi;
struct buffer_head *bh;
- unsigned int block;
u64 ctime;
unsigned long nsecs;
struct inode *inode;
@@ -204,8 +209,7 @@
if (!(inode->i_state & I_NEW))
return inode;
- block = clus_to_blk(sbi, ino);
- bh = sb_bread(inode->i_sb, block);
+ bh = omfs_bread(inode->i_sb, ino);
if (!bh)
goto iget_failed;
@@ -319,6 +323,9 @@
goto nomem;
block = clus_to_blk(sbi, sbi->s_bitmap_ino);
+ if (block >= sbi->s_num_blocks)
+ goto nomem;
+
ptr = sbi->s_imap;
for (count = bitmap_size; count > 0; count -= sb->s_blocksize) {
bh = sb_bread(sb, block++);
@@ -417,7 +424,6 @@
struct omfs_root_block *omfs_rb;
struct omfs_sb_info *sbi;
struct inode *root;
- sector_t start;
int ret = -EINVAL;
save_mount_options(sb, (char *) data);
@@ -486,8 +492,7 @@
sbi->s_block_shift = get_bitmask_order(sbi->s_blocksize) -
get_bitmask_order(sbi->s_sys_blocksize);
- start = clus_to_blk(sbi, be64_to_cpu(omfs_sb->s_root_block));
- bh2 = sb_bread(sb, start);
+ bh2 = omfs_bread(sb, be64_to_cpu(omfs_sb->s_root_block));
if (!bh2)
goto out_brelse_bh;