From 5efed5a172881f601ac3c57c22ec5c5721f895be Mon Sep 17 00:00:00 2001 From: "Gabriel L. Somlo" Date: Mon, 18 May 2015 08:47:24 -0400 Subject: [PATCH] bios-tables-test: handle false-positive smbios signature matches It has been reported that sometimes the .rodata section of SeaBIOS, containing the constant string against which the SMBIOS signature ends up being compared, also falls within the guest f-segment. In that case, the test obviously fails, unless we continue searching for the *real* SMBIOS entry point. Rather than stopping at the first match for the SMBIOS signature ("_SM_") in the f-segment (0xF0000-0xFFFFF), continue scanning until either a valid entry point table is found, or the f-segment has been exhausted. Reported-by: Bruce Rogers Signed-off-by: Gabriel Somlo Tested-by: Bruce Rogers Signed-off-by: Gerd Hoffmann --- tests/bios-tables-test.c | 78 +++++++++++++++++++++++----------------- 1 file changed, 45 insertions(+), 33 deletions(-) diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c index 7e85dc45e3..0de1742d7d 100644 --- a/tests/bios-tables-test.c +++ b/tests/bios-tables-test.c @@ -599,7 +599,45 @@ static void test_acpi_asl(test_data *data) free_test_data(&exp_data); } -static void test_smbios_ep_address(test_data *data) +static bool smbios_ep_table_ok(test_data *data) +{ + struct smbios_entry_point *ep_table = &data->smbios_ep_table; + uint32_t addr = data->smbios_ep_addr; + + ACPI_READ_ARRAY(ep_table->anchor_string, addr); + if (memcmp(ep_table->anchor_string, "_SM_", 4)) { + return false; + } + ACPI_READ_FIELD(ep_table->checksum, addr); + ACPI_READ_FIELD(ep_table->length, addr); + ACPI_READ_FIELD(ep_table->smbios_major_version, addr); + ACPI_READ_FIELD(ep_table->smbios_minor_version, addr); + ACPI_READ_FIELD(ep_table->max_structure_size, addr); + ACPI_READ_FIELD(ep_table->entry_point_revision, addr); + ACPI_READ_ARRAY(ep_table->formatted_area, addr); + ACPI_READ_ARRAY(ep_table->intermediate_anchor_string, addr); + if (memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5)) { + return false; + } + ACPI_READ_FIELD(ep_table->intermediate_checksum, addr); + ACPI_READ_FIELD(ep_table->structure_table_length, addr); + if (ep_table->structure_table_length == 0) { + return false; + } + ACPI_READ_FIELD(ep_table->structure_table_address, addr); + ACPI_READ_FIELD(ep_table->number_of_structures, addr); + if (ep_table->number_of_structures == 0) { + return false; + } + ACPI_READ_FIELD(ep_table->smbios_bcd_revision, addr); + if (acpi_checksum((uint8_t *)ep_table, sizeof *ep_table) || + acpi_checksum((uint8_t *)ep_table + 0x10, sizeof *ep_table - 0x10)) { + return false; + } + return true; +} + +static void test_smbios_entry_point(test_data *data) { uint32_t off; @@ -613,40 +651,15 @@ static void test_smbios_ep_address(test_data *data) } if (!memcmp(sig, "_SM_", sizeof sig)) { - break; + /* signature match, but is this a valid entry point? */ + data->smbios_ep_addr = off; + if (smbios_ep_table_ok(data)) { + break; + } } } g_assert_cmphex(off, <, 0x100000); - data->smbios_ep_addr = off; -} - -static void test_smbios_ep_table(test_data *data) -{ - struct smbios_entry_point *ep_table = &data->smbios_ep_table; - uint32_t addr = data->smbios_ep_addr; - - ACPI_READ_ARRAY(ep_table->anchor_string, addr); - g_assert(!memcmp(ep_table->anchor_string, "_SM_", 4)); - ACPI_READ_FIELD(ep_table->checksum, addr); - ACPI_READ_FIELD(ep_table->length, addr); - ACPI_READ_FIELD(ep_table->smbios_major_version, addr); - ACPI_READ_FIELD(ep_table->smbios_minor_version, addr); - ACPI_READ_FIELD(ep_table->max_structure_size, addr); - ACPI_READ_FIELD(ep_table->entry_point_revision, addr); - ACPI_READ_ARRAY(ep_table->formatted_area, addr); - ACPI_READ_ARRAY(ep_table->intermediate_anchor_string, addr); - g_assert(!memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5)); - ACPI_READ_FIELD(ep_table->intermediate_checksum, addr); - ACPI_READ_FIELD(ep_table->structure_table_length, addr); - g_assert_cmpuint(ep_table->structure_table_length, >, 0); - ACPI_READ_FIELD(ep_table->structure_table_address, addr); - ACPI_READ_FIELD(ep_table->number_of_structures, addr); - g_assert_cmpuint(ep_table->number_of_structures, >, 0); - ACPI_READ_FIELD(ep_table->smbios_bcd_revision, addr); - g_assert(!acpi_checksum((uint8_t *)ep_table, sizeof *ep_table)); - g_assert(!acpi_checksum((uint8_t *)ep_table + 0x10, - sizeof *ep_table - 0x10)); } static inline bool smbios_single_instance(uint8_t type) @@ -767,8 +780,7 @@ static void test_acpi_one(const char *params, test_data *data) } } - test_smbios_ep_address(data); - test_smbios_ep_table(data); + test_smbios_entry_point(data); test_smbios_structs(data); qtest_quit(global_qtest);