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authorMark Langsdorf <mlangsdo@redhat.com>2022-01-05 11:47:14 -0600
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-01-11 16:39:14 +0100
commitee3fe99ff0a27108ac38d9766ac0e92f5ec35692 (patch)
tree04191cd3135a5fc1aee346d98e9f94c5d2890c89 /drivers/acpi/spcr.c
parentbca21755b9fc00dbe371994b53389eb5d70b8e72 (diff)
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ACPI: SPCR: check if table->serial_port.access_width is too wide
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>
Diffstat (limited to 'drivers/acpi/spcr.c')
-rw-r--r--drivers/acpi/spcr.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
index 25c2d0be953e..d589543875b8 100644
--- a/drivers/acpi/spcr.c
+++ b/drivers/acpi/spcr.c
@@ -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;