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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Dongliang Mu <mudongliangabcd@gmail.com>,
	syzbot+15342c1aa6a00fb7a438@syzkaller.appspotmail.com,
	Dave Kleikamp <dave.kleikamp@oracle.com>,
	Sasha Levin <sashal@kernel.org>,
	shaggy@kernel.org, wuhoipok@gmail.com, paskripkin@gmail.com,
	r33s3n6@gmail.com, jfs-discussion@lists.sourceforge.net
Subject: [PATCH AUTOSEL 5.10 1/9] fs: jfs: fix shift-out-of-bounds in dbAllocAG
Date: Sat, 17 Dec 2022 10:29:18 -0500	[thread overview]
Message-ID: <20221217152927.99012-1-sashal@kernel.org> (raw)

From: Dongliang Mu <mudongliangabcd@gmail.com>

[ Upstream commit 898f706695682b9954f280d95e49fa86ffa55d08 ]

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 64 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. The upper bound for this
field is L2MAXL2SIZE - L2MAXAG, thanks for the help of Dave Kleikamp.
Note that, for maintenance, I reorganized error handling code of dbMount.

Reported-by: syzbot+15342c1aa6a00fb7a438@syzkaller.appspotmail.com
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/jfs/jfs_dmap.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 0ce17ea8fa8a..b0a65aaed43e 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 +193,11 @@ 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 > L2MAXL2SIZE - L2MAXAG) {
+		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 +218,12 @@ 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


             reply	other threads:[~2022-12-17 15:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-17 15:29 Sasha Levin [this message]
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 2/9] udf: Avoid double brelse() in udf_rename() Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 3/9] fs: jfs: fix shift-out-of-bounds in dbDiscardAG Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 4/9] ACPICA: Fix error code path in acpi_ds_call_control_method() Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 5/9] proc/vmcore: fix potential memory leak in vmcore_init() Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 6/9] nilfs2: fix shift-out-of-bounds/overflow in nilfs_sb2_bad_offset() Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 7/9] nilfs2: fix shift-out-of-bounds due to too large exponent of block size Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 8/9] acct: fix potential integer overflow in encode_comp_t() Sasha Levin
2022-12-17 15:29 ` [PATCH AUTOSEL 5.10 9/9] hfs: fix OOB Read in __hfs_brec_find Sasha Levin

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