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Subject[PATCH part2 4/4] acpi: Introduce acpi_verify_initrd() to check if a table is invalid.
Date
In acpi_initrd_override(), it checks several things to ensure the
table it found is valid. In later patches, we need to do these check
somewhere else. So this patch introduces a common function
acpi_verify_table() to do all these checks, and reuse it in different
places. The function will be used in the subsequent patches.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/acpi/osl.c | 86 +++++++++++++++++++++++++++++++++++++---------------
1 files changed, 61 insertions(+), 25 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3b8bab2..0043e9f 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -572,9 +572,68 @@ static const char * const table_sigs[] = {
/* Must not increase 10 or needs code modification below */
#define ACPI_OVERRIDE_TABLES 10

+/*******************************************************************************
+ *
+ * FUNCTION: acpi_verify_table
+ *
+ * PARAMETERS: File - The initrd file
+ * Path - Path to acpi overriding tables in cpio file
+ * Signature - Signature of the table
+ *
+ * RETURN: 0 if it passes all the checks, -EINVAL if any check fails.
+ *
+ * DESCRIPTION: Check if an acpi table found in initrd is invalid.
+ * @signature can be NULL. If it is NULL, the function will check
+ * if the table signature matches any signature in table_sigs[].
+ *
+ ******************************************************************************/
+int __init acpi_verify_table(struct cpio_data *file,
+ const char *path, const char *signature)
+{
+ int idx;
+ struct acpi_table_header *table = file->data;
+
+ if (file->size < sizeof(struct acpi_table_header)) {
+ ACPI_INVALID_TABLE("Table smaller than ACPI header",
+ path, file->name);
+ return -EINVAL;
+ }
+
+ if (signature) {
+ if (memcmp(table->signature, signature, 4)) {
+ ACPI_INVALID_TABLE("Table signature does not match",
+ path, file->name);
+ return -EINVAL;
+ }
+ } else {
+ for (idx = 0; table_sigs[idx]; idx++)
+ if (!memcmp(table->signature, table_sigs[idx], 4))
+ break;
+
+ if (!table_sigs[idx]) {
+ ACPI_INVALID_TABLE("Unknown signature", path, file->name);
+ return -EINVAL;
+ }
+ }
+
+ if (file->size != table->length) {
+ ACPI_INVALID_TABLE("File length does not match table length",
+ path, file->name);
+ return -EINVAL;
+ }
+
+ if (acpi_table_checksum(file->data, table->length)) {
+ ACPI_INVALID_TABLE("Bad table checksum",
+ path, file->name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
void __init acpi_initrd_override(void *data, size_t size)
{
- int sig, no, table_nr = 0, total_offset = 0;
+ int no, table_nr = 0, total_offset = 0;
long offset = 0;
struct acpi_table_header *table;
char cpio_path[32] = "kernel/firmware/acpi/";
@@ -593,33 +652,10 @@ void __init acpi_initrd_override(void *data, size_t size)
data += offset;
size -= offset;

- if (file.size < sizeof(struct acpi_table_header)) {
- ACPI_INVALID_TABLE("Table smaller than ACPI header",
- cpio_path, file.name);
- continue;
- }
-
table = file.data;

- for (sig = 0; table_sigs[sig]; sig++)
- if (!memcmp(table->signature, table_sigs[sig], 4))
- break;
-
- if (!table_sigs[sig]) {
- ACPI_INVALID_TABLE("Unknown signature",
- cpio_path, file.name);
+ if (acpi_verify_table(&file, cpio_path, NULL))
continue;
- }
- if (file.size != table->length) {
- ACPI_INVALID_TABLE("File length does not match table length",
- cpio_path, file.name);
- continue;
- }
- if (acpi_table_checksum(file.data, table->length)) {
- ACPI_INVALID_TABLE("Bad table checksum",
- cpio_path, file.name);
- continue;
- }

pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
table->signature, cpio_path, file.name, table->length);
--
1.7.1


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