Messages in this thread | | | Subject | Re: [PATCH 2/3] ceph: fix use-after-free in ceph_readdir | From | Xiubo Li <> | Date | Sat, 5 Mar 2022 20:43:04 +0800 |
| |
On 3/5/22 2:20 AM, Jeff Layton wrote: > On Fri, 2022-03-04 at 16:14 +0000, Luís Henriques wrote: >> After calling ceph_mdsc_put_request() on dfi->last_readdir, this field >> should be set to NULL, otherwise we may end-up freeing it twince and get >> the following splat: >> >> refcount_t: underflow; use-after-free. >> WARNING: CPU: 0 PID: 229 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0 >> ... >> Call Trace: >> <TASK> >> ceph_readdir+0xd35/0x1460 [ceph] >> ? _raw_spin_unlock+0x12/0x30 >> ? preempt_count_add+0x73/0xa0 >> ? _raw_spin_unlock+0x12/0x30 >> ? __mark_inode_dirty+0x27c/0x3a0 >> iterate_dir+0x7d/0x190 >> __x64_sys_getdents64+0x80/0x120 >> ? compat_fillonedir+0x160/0x160 >> do_syscall_64+0x43/0x90 >> entry_SYSCALL_64_after_hwframe+0x44/0xae >> >> Signed-off-by: Luís Henriques <lhenriques@suse.de> >> --- >> fs/ceph/dir.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c >> index 0bcb677d2199..934402f5e9e6 100644 >> --- a/fs/ceph/dir.c >> +++ b/fs/ceph/dir.c >> @@ -555,6 +555,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) >> le32_to_cpu(rde->inode.in->mode) >> 12)) { >> dout("filldir stopping us...\n"); >> ceph_mdsc_put_request(dfi->last_readdir); >> + dfi->last_readdir = NULL; >> err = 0; >> goto out; >> } > I think Xiubo fixed this in the testing branch late yesterday. It should > no longer be needed.
Right and I have sent a new version of my previous patch to remove the buggy code.
- Xiubo
> Thanks,
| |