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authorEric Sesterhenn <snakebyte@gmx.de>2009-01-06 14:43:12 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 15:59:31 -0800
commite1f89ec95bd28b0927e76c46a7cc0927b7521c1d (patch)
tree7edb722c036ee9aaec0621a25a2e58326c55fffc /fs/bfs
parent58c6d3dfe436eb8cfb451981d8fdc9044eaf42da (diff)
downloadlinux-e1f89ec95bd28b0927e76c46a7cc0927b7521c1d.tar.gz
bfs: add some basic sanity checks
bfs_fill_super() already touches all inodes, so we can easily add some cheap sanity checks and check if the inode start and end blocks are smaller than the maximum number of blocks, the inode start block lies behind the end block or the file end offset is behind the end of the filesystem. Also check if the start of data offset in the super block fits the filesystem. The added sanity checks catch softlockup issues early when we try to sb_bread() lots of blocks in a loop in bfs_readdir() and bfs_find_entry(). In addition an oom issue in bfs_fill_super() is prevented by this when s_start is corrupted, which influences imap_len and we try to allocate a huge info->si_imap. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Acked-by: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/bfs')
-rw-r--r--fs/bfs/inode.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c
index 0ed57b5ee01..1d2bfafcad7 100644
--- a/fs/bfs/inode.c
+++ b/fs/bfs/inode.c
@@ -213,6 +213,9 @@ static void bfs_put_super(struct super_block *s)
{
struct bfs_sb_info *info = BFS_SB(s);
+ if (!info)
+ return;
+
brelse(info->si_sbh);
mutex_destroy(&info->bfs_lock);
kfree(info->si_imap);
@@ -327,6 +330,7 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
unsigned i, imap_len;
struct bfs_sb_info *info;
long ret = -EINVAL;
+ unsigned long i_sblock, i_eblock, i_eoff, s_size;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
@@ -350,6 +354,12 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
s->s_magic = BFS_MAGIC;
info->si_sbh = bh;
+
+ if (le32_to_cpu(bfs_sb->s_start) > le32_to_cpu(bfs_sb->s_end)) {
+ printf("Superblock is corrupted\n");
+ goto out;
+ }
+
info->si_lasti = (le32_to_cpu(bfs_sb->s_start) - BFS_BSIZE) /
sizeof(struct bfs_inode)
+ BFS_ROOT_INO - 1;
@@ -397,6 +407,29 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent)
di = (struct bfs_inode *)bh->b_data + off;
+ /* test if filesystem is not corrupted */
+
+ i_eoff = le32_to_cpu(di->i_eoffset);
+ i_sblock = le32_to_cpu(di->i_sblock);
+ i_eblock = le32_to_cpu(di->i_eblock);
+ s_size = le32_to_cpu(bfs_sb->s_end);
+
+ if (i_sblock > info->si_blocks ||
+ i_eblock > info->si_blocks ||
+ i_sblock > i_eblock ||
+ i_eoff > s_size ||
+ i_sblock * BFS_BSIZE > i_eoff) {
+
+ printf("Inode 0x%08x corrupted\n", i);
+
+ brelse(bh);
+ s->s_root = NULL;
+ kfree(info->si_imap);
+ kfree(info);
+ s->s_fs_info = NULL;
+ return -EIO;
+ }
+
if (!di->i_ino) {
info->si_freei++;
continue;