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* [PATCH] ACPI: SPCR: check if table->serial_port.access_width is too wide
@ 2021-09-16 19:49 Mark Langsdorf
  2021-09-24 16:10 ` Rafael J. Wysocki
  0 siblings, 1 reply; 3+ messages in thread
From: Mark Langsdorf @ 2021-09-16 19:49 UTC (permalink / raw)
  To: linux-acpi

If table->serial_port.access_width is more than 29, it causes
undefined behavior when ACPI_ACCESS_BIT_WIDTH shifts it to
(1 << ((size) + 2)):

[    0.000000] UBSAN: Undefined behaviour in drivers/acpi/spcr.c:114:11
[    0.000000] shift exponent 102 is too large for 32-bit type 'int'

Test that serial_port.access_width is less than 30 and set it to 6
if it is not.

Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>
---
 drivers/acpi/spcr.c    |  8 ++++++--
 include/acpi/actypes.h | 10 ++++++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 134f7f60cf8102..52f17d631d24e9 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -111,8 +111,12 @@ int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console)
 		pr_info("SPCR table version %d\n", table->header.revision);
 
 	if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
-		switch (ACPI_ACCESS_BIT_WIDTH((
-			table->serial_port.access_width))) {
+		u32 bit_width = table->serial_port.access_width;
+		if(bit_width > ACPI_ACCESS_BIT_MAX) {
+			pr_err("Unacceptable wide SPCR Access Width.  Defaulting to byte size\n");
+			bit_width = ACPI_ACCESS_BIT_DEFAULT;
+		}
+		switch (ACPI_ACCESS_BIT_WIDTH((bit_width))) {
 		default:
 			pr_err("Unexpected SPCR Access Width.  Defaulting to byte size\n");
 			fallthrough;
diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
index 92c71dfce0d5d9..cefbb7ad253e02 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -536,8 +536,14 @@ typedef u64 acpi_integer;
  * Can be used with access_width of struct acpi_generic_address and access_size of
  * struct acpi_resource_generic_register.
  */
-#define ACPI_ACCESS_BIT_WIDTH(size)     (1 << ((size) + 2))
-#define ACPI_ACCESS_BYTE_WIDTH(size)    (1 << ((size) - 1))
+#define ACPI_ACCESS_BIT_SHIFT		2
+#define ACPI_ACCESS_BYTE_SHIFT		-1
+#define ACPI_ACCESS_BIT_MAX		(31 - ACPI_ACCESS_BIT_SHIFT)
+#define ACPI_ACCESS_BYTE_MAX		(31 - ACPI_ACCESS_BYTE_SHIFT)
+#define ACPI_ACCESS_BIT_DEFAULT		(8 - ACPI_ACCESS_BIT_SHIFT)
+#define ACPI_ACCESS_BYTE_DEFAULT	(8 - ACPI_ACCESS_BYTE_SHIFT)
+#define ACPI_ACCESS_BIT_WIDTH(size)	(1 << ((size) + ACPI_ACCESS_BIT_SHIFT))
+#define ACPI_ACCESS_BYTE_WIDTH(size)	(1 << ((size) + ACPI_ACCESS_BYTE_SHIFT))
 
 /*******************************************************************************
  *
-- 
2.26.3


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] ACPI: SPCR: check if table->serial_port.access_width is too wide
  2021-09-16 19:49 [PATCH] ACPI: SPCR: check if table->serial_port.access_width is too wide Mark Langsdorf
@ 2021-09-24 16:10 ` Rafael J. Wysocki
  2021-09-24 17:11   ` Mark Langsdorf
  0 siblings, 1 reply; 3+ messages in thread
From: Rafael J. Wysocki @ 2021-09-24 16:10 UTC (permalink / raw)
  To: Mark Langsdorf; +Cc: ACPI Devel Maling List, Robert Moore

On Thu, Sep 16, 2021 at 9:50 PM Mark Langsdorf <mlangsdo@redhat.com> wrote:
>
> If table->serial_port.access_width is more than 29, it causes
> undefined behavior when ACPI_ACCESS_BIT_WIDTH shifts it to
> (1 << ((size) + 2)):
>
> [    0.000000] UBSAN: Undefined behaviour in drivers/acpi/spcr.c:114:11
> [    0.000000] shift exponent 102 is too large for 32-bit type 'int'
>
> Test that serial_port.access_width is less than 30 and set it to 6
> if it is not.
>
> Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

This consists of a Linux part and an ACPICA part (the changes in
actypes.h).  The ACPICA part needs to be submitted to the upstream
project before applying this.

> ---
>  drivers/acpi/spcr.c    |  8 ++++++--
>  include/acpi/actypes.h | 10 ++++++++--
>  2 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
> index 134f7f60cf8102..52f17d631d24e9 100644
> --- a/drivers/acpi/spcr.c
> +++ b/drivers/acpi/spcr.c
> @@ -111,8 +111,12 @@ int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console)
>                 pr_info("SPCR table version %d\n", table->header.revision);
>
>         if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
> -               switch (ACPI_ACCESS_BIT_WIDTH((
> -                       table->serial_port.access_width))) {
> +               u32 bit_width = table->serial_port.access_width;
> +               if(bit_width > ACPI_ACCESS_BIT_MAX) {
> +                       pr_err("Unacceptable wide SPCR Access Width.  Defaulting to byte size\n");
> +                       bit_width = ACPI_ACCESS_BIT_DEFAULT;
> +               }
> +               switch (ACPI_ACCESS_BIT_WIDTH((bit_width))) {
>                 default:
>                         pr_err("Unexpected SPCR Access Width.  Defaulting to byte size\n");
>                         fallthrough;
> diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
> index 92c71dfce0d5d9..cefbb7ad253e02 100644
> --- a/include/acpi/actypes.h
> +++ b/include/acpi/actypes.h
> @@ -536,8 +536,14 @@ typedef u64 acpi_integer;
>   * Can be used with access_width of struct acpi_generic_address and access_size of
>   * struct acpi_resource_generic_register.
>   */
> -#define ACPI_ACCESS_BIT_WIDTH(size)     (1 << ((size) + 2))
> -#define ACPI_ACCESS_BYTE_WIDTH(size)    (1 << ((size) - 1))
> +#define ACPI_ACCESS_BIT_SHIFT          2
> +#define ACPI_ACCESS_BYTE_SHIFT         -1
> +#define ACPI_ACCESS_BIT_MAX            (31 - ACPI_ACCESS_BIT_SHIFT)
> +#define ACPI_ACCESS_BYTE_MAX           (31 - ACPI_ACCESS_BYTE_SHIFT)
> +#define ACPI_ACCESS_BIT_DEFAULT                (8 - ACPI_ACCESS_BIT_SHIFT)
> +#define ACPI_ACCESS_BYTE_DEFAULT       (8 - ACPI_ACCESS_BYTE_SHIFT)
> +#define ACPI_ACCESS_BIT_WIDTH(size)    (1 << ((size) + ACPI_ACCESS_BIT_SHIFT))
> +#define ACPI_ACCESS_BYTE_WIDTH(size)   (1 << ((size) + ACPI_ACCESS_BYTE_SHIFT))
>
>  /*******************************************************************************
>   *
> --
> 2.26.3
>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] ACPI: SPCR: check if table->serial_port.access_width is too wide
  2021-09-24 16:10 ` Rafael J. Wysocki
@ 2021-09-24 17:11   ` Mark Langsdorf
  0 siblings, 0 replies; 3+ messages in thread
From: Mark Langsdorf @ 2021-09-24 17:11 UTC (permalink / raw)
  To: Rafael J. Wysocki; +Cc: ACPI Devel Maling List, Robert Moore

On 9/24/21 11:10 AM, Rafael J. Wysocki wrote:
> On Thu, Sep 16, 2021 at 9:50 PM Mark Langsdorf <mlangsdo@redhat.com> wrote:
>> If table->serial_port.access_width is more than 29, it causes
>> undefined behavior when ACPI_ACCESS_BIT_WIDTH shifts it to
>> (1 << ((size) + 2)):
>>
>> [    0.000000] UBSAN: Undefined behaviour in drivers/acpi/spcr.c:114:11
>> [    0.000000] shift exponent 102 is too large for 32-bit type 'int'
>>
>> Test that serial_port.access_width is less than 30 and set it to 6
>> if it is not.
>>
>> This consists of a Linux part and an ACPICA part (the changes in
>> actypes.h).  The ACPICA part needs to be submitted to the upstream
>> project before applying this.

Thanks, I wasn't sure of the procedure. I'll get the ACPICA part 
accepted and come back with the rest.

--Mark Langsdorf


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-09-24 17:12 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-09-16 19:49 [PATCH] ACPI: SPCR: check if table->serial_port.access_width is too wide Mark Langsdorf
2021-09-24 16:10 ` Rafael J. Wysocki
2021-09-24 17:11   ` Mark Langsdorf

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