| From e1760899d4730c73c5ef3c2ba7bd7b5602ca5432 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 11 Feb 2022 02:59:15 +1000 |
| Subject: cifs: fix double free race when mount fails in cifs_get_root() |
| |
| From: Ronnie Sahlberg <lsahlber@redhat.com> |
| |
| [ Upstream commit 3d6cc9898efdfb062efb74dc18cfc700e082f5d5 ] |
| |
| When cifs_get_root() fails during cifs_smb3_do_mount() we call |
| deactivate_locked_super() which eventually will call delayed_free() which |
| will free the context. |
| In this situation we should not proceed to enter the out: section in |
| cifs_smb3_do_mount() and free the same resources a second time. |
| |
| [Thu Feb 10 12:59:06 2022] BUG: KASAN: use-after-free in rcu_cblist_dequeue+0x32/0x60 |
| [Thu Feb 10 12:59:06 2022] Read of size 8 at addr ffff888364f4d110 by task swapper/1/0 |
| |
| [Thu Feb 10 12:59:06 2022] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G OE 5.17.0-rc3+ #4 |
| [Thu Feb 10 12:59:06 2022] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.0 12/17/2019 |
| [Thu Feb 10 12:59:06 2022] Call Trace: |
| [Thu Feb 10 12:59:06 2022] <IRQ> |
| [Thu Feb 10 12:59:06 2022] dump_stack_lvl+0x5d/0x78 |
| [Thu Feb 10 12:59:06 2022] print_address_description.constprop.0+0x24/0x150 |
| [Thu Feb 10 12:59:06 2022] ? rcu_cblist_dequeue+0x32/0x60 |
| [Thu Feb 10 12:59:06 2022] kasan_report.cold+0x7d/0x117 |
| [Thu Feb 10 12:59:06 2022] ? rcu_cblist_dequeue+0x32/0x60 |
| [Thu Feb 10 12:59:06 2022] __asan_load8+0x86/0xa0 |
| [Thu Feb 10 12:59:06 2022] rcu_cblist_dequeue+0x32/0x60 |
| [Thu Feb 10 12:59:06 2022] rcu_core+0x547/0xca0 |
| [Thu Feb 10 12:59:06 2022] ? call_rcu+0x3c0/0x3c0 |
| [Thu Feb 10 12:59:06 2022] ? __this_cpu_preempt_check+0x13/0x20 |
| [Thu Feb 10 12:59:06 2022] ? lock_is_held_type+0xea/0x140 |
| [Thu Feb 10 12:59:06 2022] rcu_core_si+0xe/0x10 |
| [Thu Feb 10 12:59:06 2022] __do_softirq+0x1d4/0x67b |
| [Thu Feb 10 12:59:06 2022] __irq_exit_rcu+0x100/0x150 |
| [Thu Feb 10 12:59:06 2022] irq_exit_rcu+0xe/0x30 |
| [Thu Feb 10 12:59:06 2022] sysvec_hyperv_stimer0+0x9d/0xc0 |
| ... |
| [Thu Feb 10 12:59:07 2022] Freed by task 58179: |
| [Thu Feb 10 12:59:07 2022] kasan_save_stack+0x26/0x50 |
| [Thu Feb 10 12:59:07 2022] kasan_set_track+0x25/0x30 |
| [Thu Feb 10 12:59:07 2022] kasan_set_free_info+0x24/0x40 |
| [Thu Feb 10 12:59:07 2022] ____kasan_slab_free+0x137/0x170 |
| [Thu Feb 10 12:59:07 2022] __kasan_slab_free+0x12/0x20 |
| [Thu Feb 10 12:59:07 2022] slab_free_freelist_hook+0xb3/0x1d0 |
| [Thu Feb 10 12:59:07 2022] kfree+0xcd/0x520 |
| [Thu Feb 10 12:59:07 2022] cifs_smb3_do_mount+0x149/0xbe0 [cifs] |
| [Thu Feb 10 12:59:07 2022] smb3_get_tree+0x1a0/0x2e0 [cifs] |
| [Thu Feb 10 12:59:07 2022] vfs_get_tree+0x52/0x140 |
| [Thu Feb 10 12:59:07 2022] path_mount+0x635/0x10c0 |
| [Thu Feb 10 12:59:07 2022] __x64_sys_mount+0x1bf/0x210 |
| [Thu Feb 10 12:59:07 2022] do_syscall_64+0x5c/0xc0 |
| [Thu Feb 10 12:59:07 2022] entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| [Thu Feb 10 12:59:07 2022] Last potentially related work creation: |
| [Thu Feb 10 12:59:07 2022] kasan_save_stack+0x26/0x50 |
| [Thu Feb 10 12:59:07 2022] __kasan_record_aux_stack+0xb6/0xc0 |
| [Thu Feb 10 12:59:07 2022] kasan_record_aux_stack_noalloc+0xb/0x10 |
| [Thu Feb 10 12:59:07 2022] call_rcu+0x76/0x3c0 |
| [Thu Feb 10 12:59:07 2022] cifs_umount+0xce/0xe0 [cifs] |
| [Thu Feb 10 12:59:07 2022] cifs_kill_sb+0xc8/0xe0 [cifs] |
| [Thu Feb 10 12:59:07 2022] deactivate_locked_super+0x5d/0xd0 |
| [Thu Feb 10 12:59:07 2022] cifs_smb3_do_mount+0xab9/0xbe0 [cifs] |
| [Thu Feb 10 12:59:07 2022] smb3_get_tree+0x1a0/0x2e0 [cifs] |
| [Thu Feb 10 12:59:07 2022] vfs_get_tree+0x52/0x140 |
| [Thu Feb 10 12:59:07 2022] path_mount+0x635/0x10c0 |
| [Thu Feb 10 12:59:07 2022] __x64_sys_mount+0x1bf/0x210 |
| [Thu Feb 10 12:59:07 2022] do_syscall_64+0x5c/0xc0 |
| [Thu Feb 10 12:59:07 2022] entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| Reported-by: Shyam Prasad N <sprasad@microsoft.com> |
| Reviewed-by: Shyam Prasad N <sprasad@microsoft.com> |
| Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> |
| Signed-off-by: Steve French <stfrench@microsoft.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/cifs/cifsfs.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c |
| index 41b3c5fc958c7..f44b6f9d07776 100644 |
| --- a/fs/cifs/cifsfs.c |
| +++ b/fs/cifs/cifsfs.c |
| @@ -855,6 +855,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, |
| |
| out_super: |
| deactivate_locked_super(sb); |
| + return root; |
| out: |
| cifs_cleanup_volume_info(volume_info); |
| return root; |
| -- |
| 2.34.1 |
| |
