Re: [syzbot] [jfs?] UBSAN: array-index-out-of-bounds in diNewExt

syzbot
2023-12-12T00:30:55Z

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org.

***

Subject: [jfs?] UBSAN: array-index-out-of-bounds in diNewExt
Author: eadavis@qq.com

please test array-index-out-of-bounds in diNewExt

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git bee0e7762ad2

diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index a037ee59e398..b52f34e04f6a 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -1341,6 +1341,7 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)
*/
if (dir) {
agno = dbNextAG(JFS_SBI(pip->i_sb)->ipbmap);
+ printk("agno/dbNextAG: %d, %s\n", agno, __func__);
AG_LOCK(imap, agno);
goto tryag;
}
@@ -1356,6 +1357,7 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)

/* get the ag number of this iag */
agno = BLKTOAG(JFS_IP(pip)->agstart, JFS_SBI(pip->i_sb));
+ printk("agno/agstart: %d, %s\n", agno, __func__);
dn_numag = JFS_SBI(pip->i_sb)->bmap->db_numag;
if (agno < 0 || agno > dn_numag)
return -EIO;
@@ -1584,6 +1586,7 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)
/*
* try to allocate anywhere within the same AG as the parent inode.
*/
+ printk("agno: %d, agstart: %llu, %s\n", agno, JFS_IP(pip)->agstart, __func__);
rc = diAllocAG(imap, agno, dir, ip);

AG_UNLOCK(imap, agno);
@@ -1919,6 +1922,7 @@ static int diAllocExt(struct inomap * imap, int agno, struct inode *ip)
}
iagp = (struct iag *) mp->data;
}
+ printk("iagno: %d, %llu, %s\n", iagno, iagp->agstart, __func__);

/* using the free extent summary map, find a free extent.
*/
@@ -2179,6 +2183,9 @@ static int diNewExt(struct inomap * imap, struct iag * iagp, int extno)
/* get the ag and iag numbers for this iag.
*/
agno = BLKTOAG(le64_to_cpu(iagp->agstart), sbi);
+ if (agno > MAXAG || agno < 0)
+ return -EIO;
+
iagno = le32_to_cpu(iagp->iagnum);

/* check if this is the last free extent within the