9:47 a.m.
It is possible to cause a division error and use-after-free by querying the
nmem device before the driver data is fully initialised in nvdimm_probe. E.g
by doing
(while true; do
cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
done) &
while true; do
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
done
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
done
done
On 5.7-rc3 this causes:
[ 12.711578] divide error: 0000 [#1] SMP KASAN PTI
[ 12.712321] CPU: 0 PID: 231 Comm: cat Not tainted 5.7.0-rc3 #48
[ 12.713188] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[ 12.714857] RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
[ 12.715772] Code: ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 14 11 84 d2 74
05 80 fa 03 7e 52 8b 73 08 31 d2 89 c1 48 83 c4 08 5b 5d <f7> f6 31 d2 41 5c 83 c0
07 c1 e8 03 48 8d 84 00 8e 02 00 00 25 00
[ 12.718311] RSP: 0018:ffffc9000046fd08 EFLAGS: 00010282
[ 12.719030] RAX: 0000000000000000 RBX: ffffffffc0073aa0 RCX: 0000000000000000
[ 12.720005] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060931808
[ 12.720970] RBP: ffff88806609d018 R08: 0000000000000001 R09: ffffed100cc0a2b1
[ 12.721889] R10: ffff888066051587 R11: ffffed100cc0a2b0 R12: ffff888060931800
[ 12.722744] R13: ffff888064362000 R14: ffff88806609d018 R15: ffffffff8b1a2520
[ 12.723602] FS: 00007fd16f3d5580(0000) GS:ffff88806b400000(0000)
knlGS:0000000000000000
[ 12.724600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 12.725308] CR2: 00007fd16f1ec000 CR3: 0000000064322006 CR4: 0000000000160ef0
[ 12.726268] Call Trace:
[ 12.726633] available_slots_show+0x4e/0x120 [libnvdimm]
[ 12.727380] dev_attr_show+0x42/0x80
[ 12.727891] ? memset+0x20/0x40
[ 12.728341] sysfs_kf_seq_show+0x218/0x410
[ 12.728923] seq_read+0x389/0xe10
[ 12.729415] vfs_read+0x101/0x2d0
[ 12.729891] ksys_read+0xf9/0x1d0
[ 12.730361] ? kernel_write+0x120/0x120
[ 12.730915] do_syscall_64+0x95/0x4a0
[ 12.731435] entry_SYSCALL_64_after_hwframe+0x49/0xb3
[ 12.732163] RIP: 0033:0x7fd16f2fe4be
[ 12.732685] Code: c0 e9 c6 fe ff ff 50 48 8d 3d 2e 12 0a 00 e8 69 e9 01 00 66 0f 1f 84
00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a
c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
[ 12.735207] RSP: 002b:00007ffd3177b838 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 12.736261] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007fd16f2fe4be
[ 12.737233] RDX: 0000000000020000 RSI: 00007fd16f1ed000 RDI: 0000000000000003
[ 12.738203] RBP: 00007fd16f1ed000 R08: 00007fd16f1ec010 R09: 0000000000000000
[ 12.739172] R10: 00007fd16f3f4f70 R11: 0000000000000246 R12: 00007ffd3177ce23
[ 12.740144] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
[ 12.741139] Modules linked in: nfit libnvdimm
[ 12.741783] ---[ end trace 99532e4b82410044 ]---
[ 12.742452] RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
[ 12.743167] Code: ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 14 11 84 d2 74
05 80 fa 03 7e 52 8b 73 08 31 d2 89 c1 48 83 c4 08 5b 5d <f7> f6 31 d2 41 5c 83 c0
07 c1 e8 03 48 8d 84 00 8e 02 00 00 25 00
[ 12.745709] RSP: 0018:ffffc9000046fd08 EFLAGS: 00010282
[ 12.746340] RAX: 0000000000000000 RBX: ffffffffc0073aa0 RCX: 0000000000000000
[ 12.747209] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060931808
[ 12.748081] RBP: ffff88806609d018 R08: 0000000000000001 R09: ffffed100cc0a2b1
[ 12.748977] R10: ffff888066051587 R11: ffffed100cc0a2b0 R12: ffff888060931800
[ 12.749849] R13: ffff888064362000 R14: ffff88806609d018 R15: ffffffff8b1a2520
[ 12.750729] FS: 00007fd16f3d5580(0000) GS:ffff88806b400000(0000)
knlGS:0000000000000000
[ 12.751708] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 12.752441] CR2: 00007fd16f1ec000 CR3: 0000000064322006 CR4: 0000000000160ef0
[ 12.821357] ==================================================================
[ 12.822284] BUG: KASAN: use-after-free in __mutex_lock+0x111c/0x11a0
[ 12.823084] Read of size 4 at addr ffff888065c26238 by task reproducer/218
[ 12.823968]
[ 12.824183] CPU: 2 PID: 218 Comm: reproducer Tainted: G D 5.7.0-rc3 #48
[ 12.825167] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[ 12.826595] Call Trace:
[ 12.826926] dump_stack+0x97/0xe0
[ 12.827362] print_address_description.constprop.0+0x1b/0x210
[ 12.828111] ? __mutex_lock+0x111c/0x11a0
[ 12.828645] __kasan_report.cold+0x37/0x92
[ 12.829179] ? __mutex_lock+0x111c/0x11a0
[ 12.829706] kasan_report+0x38/0x50
[ 12.830158] __mutex_lock+0x111c/0x11a0
[ 12.830666] ? ftrace_graph_stop+0x10/0x10
[ 12.831193] ? is_nvdimm_bus+0x40/0x40 [libnvdimm]
[ 12.831820] ? mutex_trylock+0x2b0/0x2b0
[ 12.832333] ? nvdimm_probe+0x259/0x420 [libnvdimm]
[ 12.832975] ? mutex_trylock+0x2b0/0x2b0
[ 12.833500] ? nvdimm_probe+0x259/0x420 [libnvdimm]
[ 12.834122] ? prepare_ftrace_return+0xa1/0xf0
[ 12.834724] ? ftrace_graph_caller+0x6b/0xa0
[ 12.835269] ? acpi_label_write+0x390/0x390 [nfit]
[ 12.835909] ? nvdimm_probe+0x259/0x420 [libnvdimm]
[ 12.836558] ? nvdimm_probe+0x259/0x420 [libnvdimm]
[ 12.837179] nvdimm_probe+0x259/0x420 [libnvdimm]
[ 12.837802] nvdimm_bus_probe+0x110/0x6b0 [libnvdimm]
[ 12.838470] really_probe+0x212/0x9a0
[ 12.838954] driver_probe_device+0x1cd/0x300
[ 12.839511] ? driver_probe_device+0x5/0x300
[ 12.840063] device_driver_attach+0xe7/0x120
[ 12.840623] bind_store+0x18d/0x230
[ 12.841075] kernfs_fop_write+0x200/0x420
[ 12.841606] vfs_write+0x154/0x450
[ 12.842047] ksys_write+0xf9/0x1d0
[ 12.842497] ? __ia32_sys_read+0xb0/0xb0
[ 12.843010] do_syscall_64+0x95/0x4a0
[ 12.843495] entry_SYSCALL_64_after_hwframe+0x49/0xb3
[ 12.844140] RIP: 0033:0x7f5b235d3563
[ 12.844607] Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00
64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 55
c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18
[ 12.846877] RSP: 002b:00007fff1c3bc578 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 12.847822] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f5b235d3563
[ 12.848717] RDX: 0000000000000006 RSI: 000055f9576710d0 RDI: 0000000000000001
[ 12.849594] RBP: 000055f9576710d0 R08: 000000000000000a R09: 0000000000000000
[ 12.850470] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
[ 12.851333] R13: 00007f5b236a3500 R14: 0000000000000006 R15: 00007f5b236a3700
[ 12.852247]
[ 12.852466] Allocated by task 225:
[ 12.852893] save_stack+0x1b/0x40
[ 12.853310] __kasan_kmalloc.constprop.0+0xc2/0xd0
[ 12.853918] kmem_cache_alloc_node+0xef/0x270
[ 12.854475] copy_process+0x485/0x6130
[ 12.854945] _do_fork+0xf1/0xb40
[ 12.855353] __do_sys_clone+0xc3/0x100
[ 12.855843] do_syscall_64+0x95/0x4a0
[ 12.856302] entry_SYSCALL_64_after_hwframe+0x49/0xb3
[ 12.856939]
[ 12.857140] Freed by task 0:
[ 12.857522] save_stack+0x1b/0x40
[ 12.857940] __kasan_slab_free+0x12c/0x170
[ 12.858464] kmem_cache_free+0xb0/0x330
[ 12.858945] rcu_core+0x55f/0x19f0
[ 12.859385] __do_softirq+0x228/0x944
[ 12.859869]
[ 12.860075] The buggy address belongs to the object at ffff888065c26200
[ 12.860075] which belongs to the cache task_struct of size 6016
[ 12.861638] The buggy address is located 56 bytes inside of
[ 12.861638] 6016-byte region [ffff888065c26200, ffff888065c27980)
[ 12.863084] The buggy address belongs to the page:
[ 12.863702] page:ffffea0001970800 refcount:1 mapcount:0 mapping:0000000021ee3712
index:0x0 head:ffffea0001970800 order:3 compound_mapcount:0 compound_pincount:0
[ 12.865478] flags: 0x80000000010200(slab|head)
[ 12.866039] raw: 0080000000010200 0000000000000000 0000000100000001 ffff888066c0f980
[ 12.867010] raw: 0000000000000000 0000000080050005 00000001ffffffff 0000000000000000
[ 12.867986] page dumped because: kasan: bad access detected
[ 12.868696]
[ 12.868900] Memory state around the buggy address:
[ 12.869514] ffff888065c26100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 12.870414] ffff888065c26180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 12.871318] >ffff888065c26200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 12.872238] ^
[ 12.872870] ffff888065c26280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 12.873754] ffff888065c26300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 12.874640]
==================================================================
This can be prevented by setting the driver data after initialisation is
complete.
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver
infrastructure")
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Vishal Verma <vishal.l.verma(a)intel.com>
Cc: Dave Jiang <dave.jiang(a)intel.com>
Cc: Ira Weiny <ira.weiny(a)intel.com>
Cc: linux-nvdimm(a)lists.01.org
Cc: linux-kernel(a)vger.kernel.org
Cc: Coly Li <colyli(a)suse.com>
Signed-off-by: Richard Palethorpe <rpalethorpe(a)suse.com>
---
V2:
+ Reviewed by Coly and removed unecessary lock
drivers/nvdimm/dimm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 7d4ddc4d9322..3d3988e1d9a0 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -43,7 +43,6 @@ static int nvdimm_probe(struct device *dev)
if (!ndd)
return -ENOMEM;
- dev_set_drvdata(dev, ndd);
ndd->dpa.name = dev_name(dev);
ndd->ns_current = -1;
ndd->ns_next = -1;
@@ -106,6 +105,8 @@ static int nvdimm_probe(struct device *dev)
if (rc)
goto err;
+ dev_set_drvdata(dev, ndd);
+
return 0;
err:
--
2.26.2
10:36 a.m.
New subject: [PATCH v2] nvdimm: Avoid race between probe and reading device
attributes
On 2020/6/15 15:47, Richard Palethorpe wrote:
It is possible to cause a division error and use-after-free by
querying the
nmem device before the driver data is fully initialised in nvdimm_probe. E.g
by doing
(while true; do
cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
done) &
while true; do
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
done
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
done
done
On 5.7-rc3 this causes:
[snipped]
This can be prevented by setting the driver data after initialisation is
complete.
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm
device-driver infrastructure")
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Vishal Verma <vishal.l.verma(a)intel.com>
Cc: Dave Jiang <dave.jiang(a)intel.com>
Cc: Ira Weiny <ira.weiny(a)intel.com>
Cc: linux-nvdimm(a)lists.01.org
Cc: linux-kernel(a)vger.kernel.org
Cc: Coly Li <colyli(a)suse.com>
Signed-off-by: Richard Palethorpe <rpalethorpe(a)suse.com>
Reviewed-by: Coly Li <colyli(a)suse.de>
Thanks.
Coly Li
---
V2:
+ Reviewed by Coly and removed unecessary lock
drivers/nvdimm/dimm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 7d4ddc4d9322..3d3988e1d9a0 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -43,7 +43,6 @@ static int nvdimm_probe(struct device *dev)
if (!ndd)
return -ENOMEM;
- dev_set_drvdata(dev, ndd);
ndd->dpa.name = dev_name(dev);
ndd->ns_current = -1;
ndd->ns_next = -1;
@@ -106,6 +105,8 @@ static int nvdimm_probe(struct device *dev)
if (rc)
goto err;
+ dev_set_drvdata(dev, ndd);
+
return 0;
err:
11:54 a.m.
New subject: [PATCH v2] nvdimm: Avoid race between probe and reading device
attributes
Ping?
On Mon, Jun 15, 2020 at 08:47:23AM +0100, Richard Palethorpe wrote:
> It is possible to cause a division error and use-after-free by querying the
> nmem device before the driver data is fully initialised in nvdimm_probe. E.g
> by doing
>
> (while true; do
> cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
> done) &
>
> while true; do
> for i in $(seq 0 4); do
> echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
> done
> for i in $(seq 0 4); do
> echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
> done
> done
>
> On 5.7-rc3 this causes:
>
> [ 12.711578] divide error: 0000 [#1] SMP KASAN PTI
> [ 12.712321] CPU: 0 PID: 231 Comm: cat Not tainted 5.7.0-rc3 #48
> [ 12.713188] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
> [ 12.714857] RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
> [ 12.715772] Code: ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 14 11 84
d2 74 05 80 fa 03 7e 52 8b 73 08 31 d2 89 c1 48 83 c4 08 5b 5d <f7> f6 31 d2 41 5c
83 c0 07 c1 e8 03 48 8d 84 00 8e 02 00 00 25 00
> [ 12.718311] RSP: 0018:ffffc9000046fd08 EFLAGS: 00010282
> [ 12.719030] RAX: 0000000000000000 RBX: ffffffffc0073aa0 RCX: 0000000000000000
> [ 12.720005] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060931808
> [ 12.720970] RBP: ffff88806609d018 R08: 0000000000000001 R09: ffffed100cc0a2b1
> [ 12.721889] R10: ffff888066051587 R11: ffffed100cc0a2b0 R12: ffff888060931800
> [ 12.722744] R13: ffff888064362000 R14: ffff88806609d018 R15: ffffffff8b1a2520
> [ 12.723602] FS: 00007fd16f3d5580(0000) GS:ffff88806b400000(0000)
knlGS:0000000000000000
> [ 12.724600] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 12.725308] CR2: 00007fd16f1ec000 CR3: 0000000064322006 CR4: 0000000000160ef0
> [ 12.726268] Call Trace:
> [ 12.726633] available_slots_show+0x4e/0x120 [libnvdimm]
> [ 12.727380] dev_attr_show+0x42/0x80
> [ 12.727891] ? memset+0x20/0x40
> [ 12.728341] sysfs_kf_seq_show+0x218/0x410
> [ 12.728923] seq_read+0x389/0xe10
> [ 12.729415] vfs_read+0x101/0x2d0
> [ 12.729891] ksys_read+0xf9/0x1d0
> [ 12.730361] ? kernel_write+0x120/0x120
> [ 12.730915] do_syscall_64+0x95/0x4a0
> [ 12.731435] entry_SYSCALL_64_after_hwframe+0x49/0xb3
> [ 12.732163] RIP: 0033:0x7fd16f2fe4be
> [ 12.732685] Code: c0 e9 c6 fe ff ff 50 48 8d 3d 2e 12 0a 00 e8 69 e9 01 00 66 0f
1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff
77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
> [ 12.735207] RSP: 002b:00007ffd3177b838 EFLAGS: 00000246 ORIG_RAX:
0000000000000000
> [ 12.736261] RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007fd16f2fe4be
> [ 12.737233] RDX: 0000000000020000 RSI: 00007fd16f1ed000 RDI: 0000000000000003
> [ 12.738203] RBP: 00007fd16f1ed000 R08: 00007fd16f1ec010 R09: 0000000000000000
> [ 12.739172] R10: 00007fd16f3f4f70 R11: 0000000000000246 R12: 00007ffd3177ce23
> [ 12.740144] R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
> [ 12.741139] Modules linked in: nfit libnvdimm
> [ 12.741783] ---[ end trace 99532e4b82410044 ]---
> [ 12.742452] RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
> [ 12.743167] Code: ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 14 11 84
d2 74 05 80 fa 03 7e 52 8b 73 08 31 d2 89 c1 48 83 c4 08 5b 5d <f7> f6 31 d2 41 5c
83 c0 07 c1 e8 03 48 8d 84 00 8e 02 00 00 25 00
> [ 12.745709] RSP: 0018:ffffc9000046fd08 EFLAGS: 00010282
> [ 12.746340] RAX: 0000000000000000 RBX: ffffffffc0073aa0 RCX: 0000000000000000
> [ 12.747209] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888060931808
> [ 12.748081] RBP: ffff88806609d018 R08: 0000000000000001 R09: ffffed100cc0a2b1
> [ 12.748977] R10: ffff888066051587 R11: ffffed100cc0a2b0 R12: ffff888060931800
> [ 12.749849] R13: ffff888064362000 R14: ffff88806609d018 R15: ffffffff8b1a2520
> [ 12.750729] FS: 00007fd16f3d5580(0000) GS:ffff88806b400000(0000)
knlGS:0000000000000000
> [ 12.751708] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 12.752441] CR2: 00007fd16f1ec000 CR3: 0000000064322006 CR4: 0000000000160ef0
> [ 12.821357] ==================================================================
> [ 12.822284] BUG: KASAN: use-after-free in __mutex_lock+0x111c/0x11a0
> [ 12.823084] Read of size 4 at addr ffff888065c26238 by task reproducer/218
> [ 12.823968]
> [ 12.824183] CPU: 2 PID: 218 Comm: reproducer Tainted: G D 5.7.0-rc3
#48
> [ 12.825167] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
> [ 12.826595] Call Trace:
> [ 12.826926] dump_stack+0x97/0xe0
> [ 12.827362] print_address_description.constprop.0+0x1b/0x210
> [ 12.828111] ? __mutex_lock+0x111c/0x11a0
> [ 12.828645] __kasan_report.cold+0x37/0x92
> [ 12.829179] ? __mutex_lock+0x111c/0x11a0
> [ 12.829706] kasan_report+0x38/0x50
> [ 12.830158] __mutex_lock+0x111c/0x11a0
> [ 12.830666] ? ftrace_graph_stop+0x10/0x10
> [ 12.831193] ? is_nvdimm_bus+0x40/0x40 [libnvdimm]
> [ 12.831820] ? mutex_trylock+0x2b0/0x2b0
> [ 12.832333] ? nvdimm_probe+0x259/0x420 [libnvdimm]
> [ 12.832975] ? mutex_trylock+0x2b0/0x2b0
> [ 12.833500] ? nvdimm_probe+0x259/0x420 [libnvdimm]
> [ 12.834122] ? prepare_ftrace_return+0xa1/0xf0
> [ 12.834724] ? ftrace_graph_caller+0x6b/0xa0
> [ 12.835269] ? acpi_label_write+0x390/0x390 [nfit]
> [ 12.835909] ? nvdimm_probe+0x259/0x420 [libnvdimm]
> [ 12.836558] ? nvdimm_probe+0x259/0x420 [libnvdimm]
> [ 12.837179] nvdimm_probe+0x259/0x420 [libnvdimm]
> [ 12.837802] nvdimm_bus_probe+0x110/0x6b0 [libnvdimm]
> [ 12.838470] really_probe+0x212/0x9a0
> [ 12.838954] driver_probe_device+0x1cd/0x300
> [ 12.839511] ? driver_probe_device+0x5/0x300
> [ 12.840063] device_driver_attach+0xe7/0x120
> [ 12.840623] bind_store+0x18d/0x230
> [ 12.841075] kernfs_fop_write+0x200/0x420
> [ 12.841606] vfs_write+0x154/0x450
> [ 12.842047] ksys_write+0xf9/0x1d0
> [ 12.842497] ? __ia32_sys_read+0xb0/0xb0
> [ 12.843010] do_syscall_64+0x95/0x4a0
> [ 12.843495] entry_SYSCALL_64_after_hwframe+0x49/0xb3
> [ 12.844140] RIP: 0033:0x7f5b235d3563
> [ 12.844607] Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00
00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff
77 55 c3 0f 1f 40 00 48 83 ec 28 48 89 54 24 18
> [ 12.846877] RSP: 002b:00007fff1c3bc578 EFLAGS: 00000246 ORIG_RAX:
0000000000000001
> [ 12.847822] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f5b235d3563
> [ 12.848717] RDX: 0000000000000006 RSI: 000055f9576710d0 RDI: 0000000000000001
> [ 12.849594] RBP: 000055f9576710d0 R08: 000000000000000a R09: 0000000000000000
> [ 12.850470] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006
> [ 12.851333] R13: 00007f5b236a3500 R14: 0000000000000006 R15: 00007f5b236a3700
> [ 12.852247]
> [ 12.852466] Allocated by task 225:
> [ 12.852893] save_stack+0x1b/0x40
> [ 12.853310] __kasan_kmalloc.constprop.0+0xc2/0xd0
> [ 12.853918] kmem_cache_alloc_node+0xef/0x270
> [ 12.854475] copy_process+0x485/0x6130
> [ 12.854945] _do_fork+0xf1/0xb40
> [ 12.855353] __do_sys_clone+0xc3/0x100
> [ 12.855843] do_syscall_64+0x95/0x4a0
> [ 12.856302] entry_SYSCALL_64_after_hwframe+0x49/0xb3
> [ 12.856939]
> [ 12.857140] Freed by task 0:
> [ 12.857522] save_stack+0x1b/0x40
> [ 12.857940] __kasan_slab_free+0x12c/0x170
> [ 12.858464] kmem_cache_free+0xb0/0x330
> [ 12.858945] rcu_core+0x55f/0x19f0
> [ 12.859385] __do_softirq+0x228/0x944
> [ 12.859869]
> [ 12.860075] The buggy address belongs to the object at ffff888065c26200
> [ 12.860075] which belongs to the cache task_struct of size 6016
> [ 12.861638] The buggy address is located 56 bytes inside of
> [ 12.861638] 6016-byte region [ffff888065c26200, ffff888065c27980)
> [ 12.863084] The buggy address belongs to the page:
> [ 12.863702] page:ffffea0001970800 refcount:1 mapcount:0 mapping:0000000021ee3712
index:0x0 head:ffffea0001970800 order:3 compound_mapcount:0 compound_pincount:0
> [ 12.865478] flags: 0x80000000010200(slab|head)
> [ 12.866039] raw: 0080000000010200 0000000000000000 0000000100000001
ffff888066c0f980
> [ 12.867010] raw: 0000000000000000 0000000080050005 00000001ffffffff
0000000000000000
> [ 12.867986] page dumped because: kasan: bad access detected
> [ 12.868696]
> [ 12.868900] Memory state around the buggy address:
> [ 12.869514] ffff888065c26100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [ 12.870414] ffff888065c26180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> [ 12.871318] >ffff888065c26200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 12.872238] ^
> [ 12.872870] ffff888065c26280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 12.873754] ffff888065c26300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 12.874640]
> ==================================================================
>
> This can be prevented by setting the driver data after initialisation is
> complete.
>
> Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base libnvdimm
device-driver infrastructure")
> Cc: Dan Williams <dan.j.williams(a)intel.com>
> Cc: Vishal Verma <vishal.l.verma(a)intel.com>
> Cc: Dave Jiang <dave.jiang(a)intel.com>
> Cc: Ira Weiny <ira.weiny(a)intel.com>
> Cc: linux-nvdimm(a)lists.01.org
> Cc: linux-kernel(a)vger.kernel.org
> Cc: Coly Li <colyli(a)suse.com>
> Signed-off-by: Richard Palethorpe <rpalethorpe(a)suse.com>
> ---
>
> V2:
> + Reviewed by Coly and removed unecessary lock
>
> drivers/nvdimm/dimm.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
> index 7d4ddc4d9322..3d3988e1d9a0 100644
> --- a/drivers/nvdimm/dimm.c
> +++ b/drivers/nvdimm/dimm.c
> @@ -43,7 +43,6 @@ static int nvdimm_probe(struct device *dev)
> if (!ndd)
> return -ENOMEM;
>
> - dev_set_drvdata(dev, ndd);
> ndd->dpa.name = dev_name(dev);
> ndd->ns_current = -1;
> ndd->ns_next = -1;
> @@ -106,6 +105,8 @@ static int nvdimm_probe(struct device *dev)
> if (rc)
> goto err;
>
> + dev_set_drvdata(dev, ndd);
> +
> return 0;
>
> err:
> --
> 2.26.2
> _______________________________________________
> Linux-nvdimm mailing list -- linux-nvdimm(a)lists.01.org
> To unsubscribe send an email to linux-nvdimm-leave(a)lists.01.org
12:19 a.m.
Yikes, sorry this languished so long, comments below:
On Mon, Jun 15, 2020 at 12:48 AM Richard Palethorpe
<rpalethorpe(a)suse.com> wrote:
It is possible to cause a division error and use-after-free by querying the
nmem device before the driver data is fully initialised in nvdimm_probe. E.g
by doing
(while true; do
cat /sys/bus/nd/devices/nmem*/available_slots 2>&1 > /dev/null
done) &
while true; do
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/bind
done
for i in $(seq 0 4); do
echo nmem$i > /sys/bus/nd/drivers/nvdimm/unbind
done
done
On 5.7-rc3 this causes:
[ 12.711578] divide error: 0000 [#1] SMP KASAN PTI
[ 12.714857] RIP: 0010:nd_label_nfree+0x134/0x1a0 [libnvdimm]
[..]
[ 12.725308] CR2: 00007fd16f1ec000 CR3: 0000000064322006 CR4:
0000000000160ef0
[ 12.726268] Call Trace:
[ 12.726633] available_slots_show+0x4e/0x120 [libnvdimm]
[ 12.727380] dev_attr_show+0x42/0x80
[ 12.727891] ? memset+0x20/0x40
[ 12.728341] sysfs_kf_seq_show+0x218/0x410
[ 12.728923] seq_read+0x389/0xe10
[ 12.729415] vfs_read+0x101/0x2d0
[ 12.729891] ksys_read+0xf9/0x1d0
[ 12.730361] ? kernel_write+0x120/0x120
[ 12.730915] do_syscall_64+0x95/0x4a0
[ 12.731435] entry_SYSCALL_64_after_hwframe+0x49/0xb3
[..]
Fixes: 4d88a97aa9e8 ("libnvdimm, nvdimm: dimm driver and base
libnvdimm device-driver infrastructure")
Cc: Dan Williams <dan.j.williams(a)intel.com>
Cc: Vishal Verma <vishal.l.verma(a)intel.com>
Cc: Dave Jiang <dave.jiang(a)intel.com>
Cc: Ira Weiny <ira.weiny(a)intel.com>
Cc: linux-nvdimm(a)lists.01.org
Cc: linux-kernel(a)vger.kernel.org
Cc: Coly Li <colyli(a)suse.com>
Signed-off-by: Richard Palethorpe <rpalethorpe(a)suse.com>
---
V2:
+ Reviewed by Coly and removed unecessary lock
drivers/nvdimm/dimm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 7d4ddc4d9322..3d3988e1d9a0 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -43,7 +43,6 @@ static int nvdimm_probe(struct device *dev)
if (!ndd)
return -ENOMEM;
- dev_set_drvdata(dev, ndd);
ndd->dpa.name = dev_name(dev);
ndd->ns_current = -1;
ndd->ns_next = -1;
@@ -106,6 +105,8 @@ static int nvdimm_probe(struct device *dev)
if (rc)
goto err;
+ dev_set_drvdata(dev, ndd);
+
I see why this works, but I think the bug is in
available_slots_show(). It is a bug for a sysfs attribute to reference
driver-data without synchronizing against bind. So it should be
possible for probe set that pointer whenever it wants. In other words
this fix (forgive the whitespace damage from pasting).
diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index b59032e0859b..e68b17bc7aab 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -335,10 +335,8 @@ static ssize_t state_show(struct device *dev,
struct device_attribute *attr,
}
static DEVICE_ATTR_RO(state);
-static ssize_t available_slots_show(struct device *dev,
- struct device_attribute *attr, char *buf)
+static ssize_t __available_slots_show(struct nvdimm_drvdata *ndd, char *buf)
{
- struct nvdimm_drvdata *ndd = dev_get_drvdata(dev);
ssize_t rc;
u32 nfree;
@@ -356,6 +354,18 @@ static ssize_t available_slots_show(struct device *dev,
nvdimm_bus_unlock(dev);
return rc;
}
+
+static ssize_t available_slots_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t rc;
+
+ nd_device_lock(dev);
+ rc = __available_slots_show(dev_get_drvdata(dev), buf);
+ nd_device_unlock(dev);
+
+ return rc;
+}
static DEVICE_ATTR_RO(available_slots);
__weak ssize_t security_show(struct device *dev,
5:58 p.m.
New subject: [PATCH v2] nvdimm: Avoid race between probe and reading device
attributes
Hello Dan,
Dan Williams <dan.j.williams(a)intel.com> writes:
I see why this works, but I think the bug is in
available_slots_show(). It is a bug for a sysfs attribute to reference
driver-data without synchronizing against bind. So it should be
possible for probe set that pointer whenever it wants. In other words
this fix (forgive the whitespace damage from pasting).
Ah, that makes sense! I see the new patch and all is good AFAICT.
--
Thank you,
Richard.
472
days inactive
704
days old
4 comments
5 participants
participants (5)
-
Coly Li -
Dan Williams -
Michal Suchánek -
Richard Palethorpe -
Richard Palethorpe