[PATCH AUTOSEL 5.4 6/7] of/irq: Prevent device address out-of-bounds read in interrupt map walk

Sasha Levin
2024-10-12T11:30:02Z

From: Stefan Wiehler <stefan.wiehler@nokia.com>

[ Upstream commit b739dffa5d570b411d4bdf4bb9b8dfd6b7d72305 ]

When of_irq_parse_raw() is invoked with a device address smaller than
the interrupt parent node (from #address-cells property), KASAN detects
the following out-of-bounds read when populating the initial match table
(dyndbg="func of_irq_parse_* +p"):

OF: of_irq_parse_one: dev=/soc@0/picasso/watchdog, index=0
OF: parent=/soc@0/pci@878000000000/gpio0@17,0, intsize=2
OF: intspec=4
OF: of_irq_parse_raw: ipar=/soc@0/pci@878000000000/gpio0@17,0, size=2
OF: -> addrsize=3
==================================================================
BUG: KASAN: slab-out-of-bounds in of_irq_parse_raw+0x2b8/0x8d0
Read of size 4 at addr ffffff81beca5608 by task bash/764

CPU: 1 PID: 764 Comm: bash Tainted: G O 6.1.67-484c613561-nokia_sm_arm64 #1
Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2023.01-12.24.03-dirty 01/01/2023
Call trace:
dump_backtrace+0xdc/0x130
show_stack+0x1c/0x30
dump_stack_lvl+0x6c/0x84
print_report+0x150/0x448
kasan_report+0x98/0x140
__asan_load4+0x78/0xa0
of_irq_parse_raw+0x2b8/0x8d0
of_irq_parse_one+0x24c/0x270
parse_interrupts+0xc0/0x120
of_fwnode_add_links+0x100/0x2d0
fw_devlink_parse_fwtree+0x64/0xc0
device_add+0xb38/0xc30
of_device_add+0x64/0x90
of_platform_device_create_pdata+0xd0/0x170
of_platform_bus_create+0x244/0x600
of_platform_notify+0x1b0/0x254
blocking_notifier_call_chain+0x9c/0xd0
__of_changeset_entry_notify+0x1b8/0x230
__of_changeset_apply_notify+0x54/0xe4
of_overlay_fdt_apply+0xc04/0xd94
...

The buggy address belongs to the object at ffffff81beca5600
which belongs to the cache kmalloc-128 of size 128
The buggy address is located 8 bytes inside of
128-byte region [ffffff81beca5600, ffffff81beca5680)

The buggy address belongs to the physical page:
page:00000000230d3d03 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1beca4
head:00000000230d3d03 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x8000000000010200(slab|head|zone=2)
raw: 8000000000010200 0000000000000000 dead000000000122 ffffff810000c300
raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffffff81beca5500: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffffff81beca5580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffffff81beca5600: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffffff81beca5680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffffff81beca5700: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
==================================================================
OF: -> got it !

Prevent the out-of-bounds read by copying the device address into a
buffer of sufficient size.

Signed-off-by: Stefan Wiehler <stefan.wiehler@nokia.com>
Link: https://lore.kernel.org/r/20240812100652.3800963-1-stefan.wiehler@nokia.com
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/of/irq.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 352e14b007e78..ad0cb49e233ac 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -288,7 +288,8 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar
struct device_node *p;
const __be32 *addr;
u32 intsize;
- int i, res;
+ int i, res, addr_len;
+ __be32 addr_buf[3] = { 0 };

pr_debug("of_irq_parse_one: dev=%pOF, index=%d\n", device, index);

@@ -297,13 +298,19 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar
return of_irq_parse_oldworld(device, index, out_irq);

/* Get the reg property (if any) */
- addr = of_get_property(device, "reg", NULL);
+ addr = of_get_property(device, "reg", &addr_len);
+
+ /* Prevent out-of-bounds read in case of longer interrupt parent address size */
+ if (addr_len > (3 * sizeof(__be32)))
+ addr_len = 3 * sizeof(__be32);
+ if (addr)
+ memcpy(addr_buf, addr, addr_len);

/* Try the new-style interrupts-extended first */
res = of_parse_phandle_with_args(device, "interrupts-extended",
"#interrupt-cells", index, out_irq);
if (!res)
- return of_irq_parse_raw(addr, out_irq);
+ return of_irq_parse_raw(addr_buf, out_irq);

/* Look for the interrupt parent. */
p = of_irq_find_parent(device);
@@ -333,7 +340,7 @@ int of_irq_parse_one(struct device_node *device, int index, struct of_phandle_ar

/* Check if there are any interrupt-map translations to process */
- res = of_irq_parse_raw(addr, out_irq);
+ res = of_irq_parse_raw(addr_buf, out_irq);
out:
of_node_put(p);
return res;
--
2.43.0