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| author | Pavel Skripkin <paskripkin@gmail.com> | 2022-03-19 22:30:00 +0300 |
|---|---|---|
| committer | Dave Kleikamp <dave.kleikamp@oracle.com> | 2022-03-22 18:09:13 +0300 |
| commit | 2cc7cc01c15f57d056318c33705647f87dcd4aab (patch) | |
| tree | 3a17f1061f6d1cc64a5ec186266ce5bcab2acc29 /fs/jfs | |
| parent | b47d5a4f6b8d42f8a8fbe891b36215e4fddc53be (diff) | |
| download | linux-2cc7cc01c15f57d056318c33705647f87dcd4aab.tar.xz | |
jfs: fix divide error in dbNextAG
Syzbot reported divide error in dbNextAG(). The problem was in missing
validation check for malicious image.
Syzbot crafted an image with bmp->db_numag equal to 0. There wasn't any
validation checks, but dbNextAG() blindly use bmp->db_numag in divide
expression
Fix it by validating bmp->db_numag in dbMount() and return an error if
image is malicious
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+46f5c25af73eb8330eb6@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Diffstat (limited to 'fs/jfs')
| -rw-r--r-- | fs/jfs/jfs_dmap.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 91f4ec93dab1..d8502f4989d9 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -148,6 +148,7 @@ static const s8 budtab[256] = { * 0 - success * -ENOMEM - insufficient memory * -EIO - i/o error + * -EINVAL - wrong bmap data */ int dbMount(struct inode *ipbmap) { @@ -179,6 +180,12 @@ int dbMount(struct inode *ipbmap) bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree); bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage); bmp->db_numag = le32_to_cpu(dbmp_le->dn_numag); + if (!bmp->db_numag) { + release_metapage(mp); + kfree(bmp); + return -EINVAL; + } + bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag); bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref); |