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| author | Ahmed Salem <x0rw3ll@gmail.com> | 2025-04-25 22:30:27 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-06-27 13:04:15 +0300 |
| commit | e49263daf03a625528e592dd05f50a5d3ce2c8c9 (patch) | |
| tree | d1703d168f9d3a8ae0010eba11686ff7f4e36fee /include | |
| parent | 36e61683f64d2bc1a3eaf1f6efe11e3aaebf562a (diff) | |
| download | linux-e49263daf03a625528e592dd05f50a5d3ce2c8c9.tar.xz | |
ACPICA: Avoid sequence overread in call to strncmp()
[ Upstream commit 64b9dfd0776e9c38d733094859a09f13282ce6f8 ]
ACPICA commit 8b83a8d88dfec59ea147fad35fc6deea8859c58c
ap_get_table_length() checks if tables are valid by
calling ap_is_valid_header(). The latter then calls
ACPI_VALIDATE_RSDP_SIG(Table->Signature).
ap_is_valid_header() accepts struct acpi_table_header as an argument, so
the signature size is always fixed to 4 bytes.
The problem is when the string comparison is between ACPI-defined table
signature and ACPI_SIG_RSDP. Common ACPI table header specifies the
Signature field to be 4 bytes long[1], with the exception of the RSDP
structure whose signature is 8 bytes long "RSD PTR " (including the
trailing blank character)[2]. Calling strncmp(sig, rsdp_sig, 8) would
then result in a sequence overread[3] as sig would be smaller (4 bytes)
than the specified bound (8 bytes).
As a workaround, pass the bound conditionally based on the size of the
signature being passed.
Link: https://uefi.org/specs/ACPI/6.5_A/05_ACPI_Software_Programming_Model.html#system-description-table-header [1]
Link: https://uefi.org/specs/ACPI/6.5_A/05_ACPI_Software_Programming_Model.html#root-system-description-pointer-rsdp-structure [2]
Link: https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html#index-Wstringop-overread [3]
Link: https://github.com/acpica/acpica/commit/8b83a8d8
Signed-off-by: Ahmed Salem <x0rw3ll@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://patch.msgid.link/2248233.Mh6RI2rZIc@rjwysocki.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/acpi/actypes.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h index 7334037624c5..a2bf54fb946a 100644 --- a/include/acpi/actypes.h +++ b/include/acpi/actypes.h @@ -524,7 +524,7 @@ typedef u64 acpi_integer; /* Support for the special RSDP signature (8 characters) */ -#define ACPI_VALIDATE_RSDP_SIG(a) (!strncmp (ACPI_CAST_PTR (char, (a)), ACPI_SIG_RSDP, 8)) +#define ACPI_VALIDATE_RSDP_SIG(a) (!strncmp (ACPI_CAST_PTR (char, (a)), ACPI_SIG_RSDP, (sizeof(a) < 8) ? ACPI_NAMESEG_SIZE : 8)) #define ACPI_MAKE_RSDP_SIG(dest) (memcpy (ACPI_CAST_PTR (char, (dest)), ACPI_SIG_RSDP, 8)) /* Support for OEMx signature (x can be any character) */ |