diff options
| author | Dexuan Cui <decui@microsoft.com> | 2021-01-08 10:23:48 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-01-11 22:45:31 +0300 |
| commit | a58015d638cd4e4555297b04bec9b49028369075 (patch) | |
| tree | 932370060f824ca7364c2610057fb7e9adb0f229 /drivers/acpi/scan.c | |
| parent | 7c53f6b671f4aba70ff15e1b05148b10d58c2837 (diff) | |
| download | linux-a58015d638cd4e4555297b04bec9b49028369075.tar.xz | |
ACPI: scan: Harden acpi_device_add() against device ID overflows
Linux VM on Hyper-V crashes with the latest mainline:
[ 4.069624] detected buffer overflow in strcpy
[ 4.077733] kernel BUG at lib/string.c:1149!
..
[ 4.085819] RIP: 0010:fortify_panic+0xf/0x11
...
[ 4.085819] Call Trace:
[ 4.085819] acpi_device_add.cold.15+0xf2/0xfb
[ 4.085819] acpi_add_single_object+0x2a6/0x690
[ 4.085819] acpi_bus_check_add+0xc6/0x280
[ 4.085819] acpi_ns_walk_namespace+0xda/0x1aa
[ 4.085819] acpi_walk_namespace+0x9a/0xc2
[ 4.085819] acpi_bus_scan+0x78/0x90
[ 4.085819] acpi_scan_init+0xfa/0x248
[ 4.085819] acpi_init+0x2c1/0x321
[ 4.085819] do_one_initcall+0x44/0x1d0
[ 4.085819] kernel_init_freeable+0x1ab/0x1f4
This is because of the recent buffer overflow detection in the
commit 6a39e62abbaf ("lib: string.h: detect intra-object overflow in
fortified string functions")
Here acpi_device_bus_id->bus_id can only hold 14 characters, while the
the acpi_device_hid(device) returns a 22-char string
"HYPER_V_GEN_COUNTER_V1".
Per ACPI Spec v6.2, Section 6.1.5 _HID (Hardware ID), if the ID is a
string, it must be of the form AAA#### or NNNN####, i.e. 7 chars or 8
chars.
The field bus_id in struct acpi_device_bus_id was originally defined as
char bus_id[9], and later was enlarged to char bus_id[15] in 2007 in the
commit bb0958544f3c ("ACPI: use more understandable bus_id for ACPI
devices")
Fix the issue by changing the field bus_id to const char *, and use
kstrdup_const() to initialize it.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Tested-By: Jethro Beekman <jethro@fortanix.com>
[ rjw: Subject change, whitespace adjustment ]
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/scan.c')
| -rw-r--r-- | drivers/acpi/scan.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 80b668c80073..58ff36340cd7 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -486,6 +486,7 @@ static void acpi_device_del(struct acpi_device *device) acpi_device_bus_id->instance_no--; else { list_del(&acpi_device_bus_id->node); + kfree_const(acpi_device_bus_id->bus_id); kfree(acpi_device_bus_id); } break; @@ -674,7 +675,14 @@ int acpi_device_add(struct acpi_device *device, } if (!found) { acpi_device_bus_id = new_bus_id; - strcpy(acpi_device_bus_id->bus_id, acpi_device_hid(device)); + acpi_device_bus_id->bus_id = + kstrdup_const(acpi_device_hid(device), GFP_KERNEL); + if (!acpi_device_bus_id->bus_id) { + pr_err(PREFIX "Memory allocation error for bus id\n"); + result = -ENOMEM; + goto err_free_new_bus_id; + } + acpi_device_bus_id->instance_no = 0; list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list); } @@ -709,6 +717,11 @@ int acpi_device_add(struct acpi_device *device, if (device->parent) list_del(&device->node); list_del(&device->wakeup_list); + + err_free_new_bus_id: + if (!found) + kfree(new_bus_id); + mutex_unlock(&acpi_device_lock); err_detach: |