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ACPI: SPCR: check if table->serial_port.access_width is too wide

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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'

Use the new ACPI_ACCESS_ defines to 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>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Mark Langsdorf 2022-01-05 11:47:14 -06:00 committed by Rafael J. Wysocki
parent bca21755b9
commit ee3fe99ff0
1 changed files with 7 additions and 2 deletions
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9
drivers/acpi/spcr.c
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@ -107,8 +107,13 @@ 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;