From: Dongliang Mu <dzm91@hust.edu.cn>
To: Dave Kleikamp <shaggy@kernel.org>
Cc: Dongliang Mu <mudongliangabcd@gmail.com>,
syzbot+15342c1aa6a00fb7a438@syzkaller.appspotmail.com,
jfs-discussion@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: [PATCH] fs: jfs: fix shift-out-of-bounds in dbAllocAG
Date: Thu, 29 Sep 2022 13:44:59 +0800 [thread overview]
Message-ID: <20220929054500.488604-1-dzm91@hust.edu.cn> (raw)
From: Dongliang Mu <mudongliangabcd@gmail.com>
Syzbot found a crash : UBSAN: shift-out-of-bounds in dbAllocAG. The
underlying bug is the missing check of bmp->db_agl2size. The field can
be greater than 32 and trigger the shift-out-of-bounds.
Fix this bug by adding a check of bmp->db_agl2size in dbMount since this
field is used in many following functions. Note that, for maintainance,
I reorganzie the error handling code of dbMount.
Reported-by: syzbot+15342c1aa6a00fb7a438@syzkaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
fs/jfs/jfs_dmap.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 6b838d3ae7c2..4c717f245920 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -155,7 +155,7 @@ int dbMount(struct inode *ipbmap)
struct bmap *bmp;
struct dbmap_disk *dbmp_le;
struct metapage *mp;
- int i;
+ int i, err;
/*
* allocate/initialize the in-memory bmap descriptor
@@ -170,8 +170,8 @@ int dbMount(struct inode *ipbmap)
BMAPBLKNO << JFS_SBI(ipbmap->i_sb)->l2nbperpage,
PSIZE, 0);
if (mp == NULL) {
- kfree(bmp);
- return -EIO;
+ err = -EIO;
+ goto err_kfree_bmp;
}
/* copy the on-disk bmap descriptor to its in-memory version. */
@@ -181,9 +181,8 @@ int dbMount(struct inode *ipbmap)
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;
+ err = -EINVAL;
+ goto err_release_metapage;
}
bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel);
@@ -194,6 +193,10 @@ int dbMount(struct inode *ipbmap)
bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);
bmp->db_agstart = le32_to_cpu(dbmp_le->dn_agstart);
bmp->db_agl2size = le32_to_cpu(dbmp_le->dn_agl2size);
+ if (bmp->db_agl2size >= 32) {
+ err = -EINVAL;
+ goto err_release_metapage;
+ }
for (i = 0; i < MAXAG; i++)
bmp->db_agfree[i] = le64_to_cpu(dbmp_le->dn_agfree[i]);
bmp->db_agsize = le64_to_cpu(dbmp_le->dn_agsize);
@@ -214,6 +217,12 @@ int dbMount(struct inode *ipbmap)
BMAP_LOCK_INIT(bmp);
return (0);
+
+err_release_metapage:
+ release_metapage(mp);
+err_kfree_bmp:
+ kfree(bmp);
+ return err;
}
--
2.35.1
next reply other threads:[~2022-09-29 5:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-29 5:44 Dongliang Mu [this message]
2022-10-09 2:00 ` [PATCH] fs: jfs: fix shift-out-of-bounds in dbAllocAG Dongliang Mu
2022-10-10 14:13 ` Dave Kleikamp
2022-10-13 20:55 ` Dave Kleikamp
2022-10-14 8:45 ` Dongliang Mu
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