Re: [Ocfs2-devel] [PATCH] ocfs2: quota_local: fix mount crash of filesystems with quota enabled
From: Joseph Qi
Date: Tue Mar 22 2022 - 03:32:45 EST
On 3/22/22 11:12 AM, Valentin Vidic via Ocfs2-devel wrote:
> ocfs2_qinfo_lock_res_init is called too early while oinfo->dqi_gi.dqi_sb
> is still a NULL pointer causing a crash on mount when quotas are enabled.
> Restore ocfs2_qinfo_lock_res_init original call location in
> ocfs2_global_read_info after the value of oinfo->dqi_gi.dqi_sb is set.
>
> [ 389.111864] ocfs2: Mounting device (254,16) on (node 2, slot 0) with ordered data mode.
> [ 389.160182] BUG: kernel NULL pointer dereference, address: 0000000000000398
> [ 389.160295] #PF: supervisor read access in kernel mode
> [ 389.160343] #PF: error_code(0x0000) - not-present page
> [ 389.160390] PGD 0 P4D 0
> [ 389.160432] Oops: 0000 [#1] PREEMPT SMP PTI
> [ 389.160477] CPU: 0 PID: 836 Comm: mount.ocfs2 Not tainted 5.16.0-4-amd64 #1 Debian 5.16.12-1
> [ 389.160591] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
> [ 389.160714] RIP: 0010:ocfs2_qinfo_lock_res_init+0x44/0x50 [ocfs2]
> [ 389.161290] Code: 00 00 00 48 63 b3 b8 01 00 00 e8 87 bb ff ff 49 89 d8 48 89 ee ba 08 00 00 00 48 8b 83 b0 01 00 00 48 c7 c1 a0 e0 dc c0 5b 5d <48> 8b b8 98 03 00 00 e9 70 c4 ff ff 0f 1f 44 00 00 41 56 41 89 ce
> [ 389.161460] RSP: 0018:ffffb2c0c0047be8 EFLAGS: 00010282
> [ 389.161510] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffffc0dce0a0
> [ 389.161619] RDX: 0000000000000008 RSI: ffff8b685c343c30 RDI: ffffb2c0c0047bb8
> [ 389.161747] RBP: ffff8b685c343c00 R08: ffff8b685c343c00 R09: 0000000000000000
> [ 389.161809] R10: ffffb2c0c0047bb0 R11: ffffffffc0d8f030 R12: ffff8b685c343c18
> [ 389.161868] R13: ffff8b68462d3ec8 R14: 0000000000000000 R15: ffff8b6848fb6800
> [ 389.161929] FS: 00007f7956901c00(0000) GS:ffff8b687ec00000(0000) knlGS:0000000000000000
> [ 389.162009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 389.162060] CR2: 0000000000000398 CR3: 000000000554a004 CR4: 0000000000370ef0
> [ 389.162129] Call Trace:
> [ 389.162184] <TASK>
> [ 389.162211] ocfs2_local_read_info+0xb9/0x6f0 [ocfs2]
> [ 389.162479] ? ocfs2_local_check_quota_file+0x197/0x390 [ocfs2]
> [ 389.162774] dquot_load_quota_sb+0x216/0x470
> [ 389.162849] ? preempt_count_add+0x68/0xa0
> [ 389.162895] dquot_load_quota_inode+0x85/0x100
> [ 389.162943] ocfs2_enable_quotas+0xa0/0x1c0 [ocfs2]
> [ 389.163151] ocfs2_fill_super.cold+0xc8/0x1bf [ocfs2]
> [ 389.163374] mount_bdev+0x185/0x1b0
> [ 389.163431] ? ocfs2_initialize_super.isra.0+0xf40/0xf40 [ocfs2]
> [ 389.163673] legacy_get_tree+0x27/0x40
> [ 389.163726] vfs_get_tree+0x25/0xb0
> [ 389.163764] path_mount+0x465/0xac0
> [ 389.163804] __x64_sys_mount+0x103/0x140
> [ 389.163844] do_syscall_64+0x3b/0xc0
> [ 389.163919] entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 389.164016] RIP: 0033:0x7f7956e0258a
> [ 389.164057] Code: 48 8b 0d e9 28 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b6 28 0d 00 f7 d8 64 89 01 48
> [ 389.164206] RSP: 002b:00007fff9be78718 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
> [ 389.164273] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7956e0258a
> [ 389.164334] RDX: 000055bffbe230ae RSI: 000055bffc7ec370 RDI: 000055bffc7f33f0
> [ 389.164395] RBP: 00007fff9be788d0 R08: 000055bffc7f3390 R09: 00007fff9be76110
> [ 389.164454] R10: 0000000000000000 R11: 0000000000000246 R12: 000055bffbe230ae
> [ 389.164514] R13: 000055bffc7ec301 R14: 00007fff9be787c0 R15: 00007fff9be78740
> [ 389.166469] </TASK>
> [ 389.168355] Modules linked in: ocfs2 quota_tree ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue sctp ip6_udp_tunnel udp_tunnel libcrc32c intel_rapl_msr intel_rapl_common intel_pmc_core_pltdrv intel_pmc_core kvm_intel kvm irqbypass ghash_clmulni_intel snd_hda_codec_generic ledtrig_audio snd_hda_intel snd_intel_dspcfg snd_intel_sdw_acpi aesni_intel crypto_simd qxl snd_hda_codec cryptd drm_ttm_helper rapl snd_hda_core ttm snd_hwdep snd_pcm serio_raw snd_timer iTCO_wdt pcspkr intel_pmc_bxt iTCO_vendor_support drm_kms_helper snd virtio_rng rng_core soundcore virtio_balloon virtio_console cec evdev joydev i6300esb rc_core watchdog qemu_fw_cfg button auth_rpcgss sunrpc drm fuse configfs ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 crc32c_generic hid_generic usbhid hid virtio_net net_failover failover virtio_blk ahci xhci_pci libahci libata xhci_hcd crct10dif_pclmul crct10dif_common crc32_pclmul crc32c_intel virtio_pci virtio_pci_legacy_dev virtio_pci_modern
> _dev
> [ 389.168645] virtio psmouse usbcore scsi_mod i2c_i801 i2c_smbus scsi_common lpc_ich usb_common virtio_ring
> [ 389.187016] CR2: 0000000000000398
> [ 389.188963] ---[ end trace 571e3ca036b59855 ]---
>
> Fixes: 6c85c2c72819 ("ocfs2: quota_local: fix possible uninitialized-variable access in ocfs2_local_read_info()")
> Reported-by: Dayvison <sathlerds@xxxxxxxxx>
> Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1007141
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Valentin Vidic <vvidic@xxxxxxxxxxxxxxxxxxxxxx>
> ---
> fs/ocfs2/quota_global.c | 1 +
> fs/ocfs2/quota_local.c | 1 -
> 2 files changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
> index f033de733adb..eda83487c9ec 100644
> --- a/fs/ocfs2/quota_global.c
> +++ b/fs/ocfs2/quota_global.c
> @@ -357,6 +357,7 @@ int ocfs2_global_read_info(struct super_block *sb, int type)
> }
> oinfo->dqi_gi.dqi_sb = sb;
> oinfo->dqi_gi.dqi_type = type;
> + ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
> oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
> oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
> oinfo->dqi_gqi_bh = NULL;
> diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
> index 0e4b16d4c037..e6037e4a1641 100644
> --- a/fs/ocfs2/quota_local.c
> +++ b/fs/ocfs2/quota_local.c
> @@ -703,7 +703,6 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
> oinfo->dqi_type = type;
> INIT_LIST_HEAD(&oinfo->dqi_chunk);
> oinfo->dqi_gqinode = NULL;
> - ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
> oinfo->dqi_rec = NULL;
> oinfo->dqi_lqi_bh = NULL;
> oinfo->dqi_libh = NULL;
Thanks for pointing this out. My fault when reviewing the introduced commit.
But this change will lead to access uninitialized dqi_gqlock when
ocfs2_global_read_info() fails.
How about the following way?
diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index f033de733adb..effe92c7d693 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -337,7 +337,6 @@ void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
/* Read information header from global quota file */
int ocfs2_global_read_info(struct super_block *sb, int type)
{
- struct inode *gqinode = NULL;
unsigned int ino[OCFS2_MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE,
GROUP_QUOTA_SYSTEM_INODE };
struct ocfs2_global_disk_dqinfo dinfo;
@@ -346,29 +345,31 @@ int ocfs2_global_read_info(struct super_block *sb, int type)
u64 pcount;
int status;
+ oinfo->dqi_gi.dqi_sb = sb;
+ oinfo->dqi_gi.dqi_type = type;
+ ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
+ oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
+ oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
+ oinfo->dqi_gqi_bh = NULL;
+ oinfo->dqi_gqi_count = 0;
+
/* Read global header */
- gqinode = ocfs2_get_system_file_inode(OCFS2_SB(sb), ino[type],
+ oinfo->dqi_gqinode = ocfs2_get_system_file_inode(OCFS2_SB(sb), ino[type],
OCFS2_INVALID_SLOT);
- if (!gqinode) {
+ if (!oinfo->dqi_gqinode) {
mlog(ML_ERROR, "failed to get global quota inode (type=%d)\n",
type);
status = -EINVAL;
goto out_err;
}
- oinfo->dqi_gi.dqi_sb = sb;
- oinfo->dqi_gi.dqi_type = type;
- oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
- oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
- oinfo->dqi_gqi_bh = NULL;
- oinfo->dqi_gqi_count = 0;
- oinfo->dqi_gqinode = gqinode;
+
status = ocfs2_lock_global_qf(oinfo, 0);
if (status < 0) {
mlog_errno(status);
goto out_err;
}
- status = ocfs2_extent_map_get_blocks(gqinode, 0, &oinfo->dqi_giblk,
+ status = ocfs2_extent_map_get_blocks(oinfo->dqi_gqinode, 0, &oinfo->dqi_giblk,
&pcount, NULL);
if (status < 0)
goto out_unlock;
diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index 0e4b16d4c037..b1a8b046f4c2 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -702,8 +702,6 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
info->dqi_priv = oinfo;
oinfo->dqi_type = type;
INIT_LIST_HEAD(&oinfo->dqi_chunk);
- oinfo->dqi_gqinode = NULL;
- ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
oinfo->dqi_rec = NULL;
oinfo->dqi_lqi_bh = NULL;
oinfo->dqi_libh = NULL;