From: Zhe Li <lizhe67@huawei.com>
To: <dwmw2@infradead.org>, <richard@nod.at>,
<linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Cc: <lizhe67@huawei.com>, <wangfangpeng1@huawei.com>,
<qiuxi1@huawei.com>, <zhongjubin@huawei.com>,
<chenjie6@huawei.com>
Subject: [PATCH] jffs2: fix UAF problem
Date: Fri, 19 Jun 2020 17:06:35 +0800 [thread overview]
Message-ID: <20200619090635.58548-1-lizhe67@huawei.com> (raw)
The log of UAF problem is listed below.
BUG: KASAN: use-after-free in jffs2_rmdir+0xa4/0x1cc [jffs2] at addr c1f165fc
Read of size 4 by task rm/8283
=============================================================================
BUG kmalloc-32 (Tainted: P B O ): kasan: bad access detected
-----------------------------------------------------------------------------
INFO: Allocated in 0xbbbbbbbb age=3054364 cpu=0 pid=0
0xb0bba6ef
jffs2_write_dirent+0x11c/0x9c8 [jffs2]
__slab_alloc.isra.21.constprop.25+0x2c/0x44
__kmalloc+0x1dc/0x370
jffs2_write_dirent+0x11c/0x9c8 [jffs2]
jffs2_do_unlink+0x328/0x5fc [jffs2]
jffs2_rmdir+0x110/0x1cc [jffs2]
vfs_rmdir+0x180/0x268
do_rmdir+0x2cc/0x300
ret_from_syscall+0x0/0x3c
INFO: Freed in 0x205b age=3054364 cpu=0 pid=0
0x2e9173
jffs2_add_fd_to_list+0x138/0x1dc [jffs2]
jffs2_add_fd_to_list+0x138/0x1dc [jffs2]
jffs2_garbage_collect_dirent.isra.3+0x21c/0x288 [jffs2]
jffs2_garbage_collect_live+0x16bc/0x1800 [jffs2]
jffs2_garbage_collect_pass+0x678/0x11d4 [jffs2]
jffs2_garbage_collect_thread+0x1e8/0x3b0 [jffs2]
kthread+0x1a8/0x1b0
ret_from_kernel_thread+0x5c/0x64
Call Trace:
[c17ddd20] [c02452d4] kasan_report.part.0+0x298/0x72c (unreliable)
[c17ddda0] [d2509680] jffs2_rmdir+0xa4/0x1cc [jffs2]
[c17dddd0] [c026da04] vfs_rmdir+0x180/0x268
[c17dde00] [c026f4e4] do_rmdir+0x2cc/0x300
[c17ddf40] [c001a658] ret_from_syscall+0x0/0x3c
The root cause is that we don't get "jffs2_inode_info.sem" before
we scan list "jffs2_inode_info.dents" in function jffs2_rmdir.
This patch add codes to get "jffs2_inode_info.sem" before we scan
"jffs2_inode_info.dents" to slove the UAF problem.
Signed-off-by: Zhe Li <lizhe67@huawei.com>
---
fs/jffs2/dir.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index f20cff1..7764937 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -590,10 +590,14 @@ static int jffs2_rmdir (struct inode *dir_i, struct dentry *dentry)
int ret;
uint32_t now = JFFS2_NOW();
+ mutex_lock(&f->sem);
for (fd = f->dents ; fd; fd = fd->next) {
- if (fd->ino)
+ if (fd->ino) {
+ mutex_unlock(&f->sem);
return -ENOTEMPTY;
+ }
}
+ mutex_unlock(&f->sem);
ret = jffs2_do_unlink(c, dir_f, dentry->d_name.name,
dentry->d_name.len, f, now);
--
2.7.4
next reply other threads:[~2020-06-19 9:07 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 9:06 Zhe Li [this message]
2020-06-22 7:25 ` [PATCH] jffs2: fix UAF problem Hou Tao
2020-06-24 18:59 ` Joakim Tjernlund
2020-07-07 14:05 ` Joakim Tjernlund
2020-07-07 16:30 ` Richard Weinberger
2020-07-13 21:51 ` Joakim Tjernlund
2020-07-15 7:49 ` Richard Weinberger
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