2023-08-05 09:09:41

by Andrey Skvortsov

[permalink] [raw]
Subject: [PATCH] clk: fix slab-out-of-bounds error in devm_clk_release

Problem can be reproduces by unloading snd_soc_simple_card, because in
devm_get_clk_from_child data were allocated as `struct clk`,
but devm_clk_release expects `struct devm_clk_state`.

KASAN report:
==================================================================
BUG: KASAN: slab-out-of-bounds in devm_clk_release+0x20/0x54
Read of size 8 at addr ffffff800ee09688 by task (udev-worker)/287

Call trace:
dump_backtrace+0xe8/0x11c
show_stack+0x1c/0x30
dump_stack_lvl+0x60/0x78
print_report+0x150/0x450
kasan_report+0xa8/0xf0
__asan_load8+0x78/0xa0
devm_clk_release+0x20/0x54
release_nodes+0x84/0x120
devres_release_all+0x144/0x210
device_unbind_cleanup+0x1c/0xac
really_probe+0x2f0/0x5b0
__driver_probe_device+0xc0/0x1f0
driver_probe_device+0x68/0x120
__driver_attach+0x140/0x294
bus_for_each_dev+0xec/0x160
driver_attach+0x38/0x44
bus_add_driver+0x24c/0x300
driver_register+0xf0/0x210
__platform_driver_register+0x48/0x54
asoc_simple_card_init+0x24/0x1000 [snd_soc_simple_card]
do_one_initcall+0xac/0x340
do_init_module+0xd0/0x300
load_module+0x2ba4/0x3100
__do_sys_init_module+0x2c8/0x300
__arm64_sys_init_module+0x48/0x5c
invoke_syscall+0x64/0x190
el0_svc_common.constprop.0+0x124/0x154
do_el0_svc+0x44/0xdc
el0_svc+0x14/0x50
el0t_64_sync_handler+0xec/0x11c
el0t_64_sync+0x14c/0x150

Allocated by task 287:
kasan_save_stack+0x38/0x60
kasan_set_track+0x28/0x40
kasan_save_alloc_info+0x20/0x30
__kasan_kmalloc+0xac/0xb0
__kmalloc_node_track_caller+0x6c/0x1c4
__devres_alloc_node+0x44/0xb4
devm_get_clk_from_child+0x44/0xa0
asoc_simple_parse_clk+0x1b8/0x1dc [snd_soc_simple_card_utils]
simple_parse_node.isra.0+0x1ec/0x230 [snd_soc_simple_card]
simple_dai_link_of+0x1bc/0x334 [snd_soc_simple_card]
__simple_for_each_link+0x2ec/0x320 [snd_soc_simple_card]
asoc_simple_probe+0x468/0x4dc [snd_soc_simple_card]
platform_probe+0x90/0xf0
really_probe+0x118/0x5b0
__driver_probe_device+0xc0/0x1f0
driver_probe_device+0x68/0x120
__driver_attach+0x140/0x294
bus_for_each_dev+0xec/0x160
driver_attach+0x38/0x44
bus_add_driver+0x24c/0x300
driver_register+0xf0/0x210
__platform_driver_register+0x48/0x54
asoc_simple_card_init+0x24/0x1000 [snd_soc_simple_card]
do_one_initcall+0xac/0x340
do_init_module+0xd0/0x300
load_module+0x2ba4/0x3100
__do_sys_init_module+0x2c8/0x300
__arm64_sys_init_module+0x48/0x5c
invoke_syscall+0x64/0x190
el0_svc_common.constprop.0+0x124/0x154
do_el0_svc+0x44/0xdc
el0_svc+0x14/0x50
el0t_64_sync_handler+0xec/0x11c
el0t_64_sync+0x14c/0x150

The buggy address belongs to the object at ffffff800ee09600
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 136 bytes inside of
256-byte region [ffffff800ee09600, ffffff800ee09700)

The buggy address belongs to the physical page:
page:000000002d97303b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4ee08
head:000000002d97303b order:1 compound_mapcount:0 compound_pincount:0
flags: 0x10200(slab|head|zone=0)
raw: 0000000000010200 0000000000000000 dead000000000122 ffffff8002c02480
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffffff800ee09580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffffff800ee09600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffff800ee09680: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffffff800ee09700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffffff800ee09780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
```
Fixes: abae8e57e49a ("clk: generalize devm_clk_get() a bit")
Signed-off-by: Andrey Skvortsov <[email protected]>
---
drivers/clk/clk-devres.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index 4fb4fd4b06bd..47d1e3d0d32c 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -205,18 +205,20 @@ EXPORT_SYMBOL(devm_clk_put);
struct clk *devm_get_clk_from_child(struct device *dev,
struct device_node *np, const char *con_id)
{
- struct clk **ptr, *clk;
+ struct devm_clk_state *state;
+ struct clk *clk;

- ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
- if (!ptr)
+ state = devres_alloc(devm_clk_release, sizeof(*state), GFP_KERNEL);
+ if (!state)
return ERR_PTR(-ENOMEM);
+ state->exit = NULL;

clk = of_clk_get_by_name(np, con_id);
if (!IS_ERR(clk)) {
- *ptr = clk;
- devres_add(dev, ptr);
+ state->clk = clk;
+ devres_add(dev, state);
} else {
- devres_free(ptr);
+ devres_free(state);
}

return clk;
--
2.40.1



2023-08-23 08:43:33

by Stephen Boyd

[permalink] [raw]
Subject: Re: [PATCH] clk: fix slab-out-of-bounds error in devm_clk_release

Quoting Andrey Skvortsov (2023-08-05 01:48:47)
> Problem can be reproduces by unloading snd_soc_simple_card, because in
> devm_get_clk_from_child data were allocated as `struct clk`,
> but devm_clk_release expects `struct devm_clk_state`.
>
[...]
> Fixes: abae8e57e49a ("clk: generalize devm_clk_get() a bit")
> Signed-off-by: Andrey Skvortsov <[email protected]>
> ---

Applied to clk-fixes but I removed the state->exit assignment because
that's the default. I also noticed that devm_clk_put() is broken in a
similar way. Sheesh!