Adds an API that verifies a signature attached to an image (binary
blob). This API is basically a entry to a secure ROM service provided by
the device and accessed via an SMC call, using a particular calling
convention.
Signed-off-by: Daniel Allred <d-all...@ti.com>
Signed-off-by: Andreas Dannenberg <dannenb...@ti.com>
---
arch/arm/cpu/armv7/omap-common/sec-common.c | 76 +++++++++++++++++++++++++++++
arch/arm/include/asm/omap_common.h | 9 ++++
2 files changed, 85 insertions(+)
diff --git a/arch/arm/cpu/armv7/omap-common/sec-common.c
b/arch/arm/cpu/armv7/omap-common/sec-common.c
index b9c0a42..dbb9078 100644
--- a/arch/arm/cpu/armv7/omap-common/sec-common.c
+++ b/arch/arm/cpu/armv7/omap-common/sec-common.c
@@ -16,6 +16,9 @@
#include <asm/arch/sys_proto.h>
#include <asm/omap_common.h>
+/* Index for signature verify ROM API */
+#define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX (0x0000000E)
+
static uint32_t secure_rom_call_args[5] __aligned(ARCH_DMA_MINALIGN);
u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...)
@@ -47,3 +50,76 @@ u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...)
return omap_smc_sec(service, proc_id, flag, secure_rom_call_args);
}
+
+static u32 find_sig_start(char *image, size_t size)
+{
+ char *image_end = image + size;
+ char *sig_start_magic = "CERT_";
+ int magic_str_len = strlen(sig_start_magic);
+ char *ch;
+
+ while (--image_end > image) {
+ if (*image_end == '_') {
+ ch = image_end - magic_str_len + 1;
+ if (!strncmp(ch, sig_start_magic, magic_str_len))
+ return (u32)ch;
+ }
+ }
+ return 0;
+}
+
+int secure_boot_verify_image(void **image, size_t *size)
+{
+ int result = 1;
+ u32 cert_addr, sig_addr;
+ size_t cert_size;
+
+ /* Perform cache writeback on input buffer */
+ flush_dcache_range(
+ (u32)*image,
+ (u32)*image + roundup(*size, ARCH_DMA_MINALIGN));
+
+ cert_addr = (uint32_t)*image;
+ sig_addr = find_sig_start((char *)*image, *size);
+
+ if (sig_addr == 0) {
+ printf("No signature found in image.\n");
+ result = 1;
+ goto auth_exit;
+ }
+
+ *size = sig_addr - cert_addr; /* Subtract out the signature size */
+ cert_size = *size;
+
+ /* Check if image load address is 32-bit aligned */
+ if (0 != (0x3 & cert_addr)) {
+ printf("Image is not 4-byte aligned.\n");
+ result = 1;
+ goto auth_exit;
+ }
+
+ /* Image size also should be multiple of 4 */
+ if (0 != (0x3 & cert_size)) {
+ printf("Image size is not 4-byte aligned.\n");
+ result = 1;
+ goto auth_exit;
+ }
+
+ /* Call ROM HAL API to verify certificate signature */
+ debug("%s: load_addr = %x, size = %x, sig_addr = %x\n", __func__,
+ cert_addr, cert_size, sig_addr);
+
+ result = secure_rom_call(
+ API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX, 0, 0,
+ 4, cert_addr, cert_size, sig_addr, 0xFFFFFFFF);
+auth_exit:
+ if (result != 0) {
+ printf("Authentication failed!\n");
+ printf("Return Value = %08X\n", result);
+ hang();
+ }
+
+ printf("Authentication passed: %s\n", (char *)sig_addr);
+
+ return result;
+}
diff --git a/arch/arm/include/asm/omap_common.h
b/arch/arm/include/asm/omap_common.h
index 293fc72..8887335 100644
--- a/arch/arm/include/asm/omap_common.h
+++ b/arch/arm/include/asm/omap_common.h
@@ -640,6 +640,15 @@ u32 omap_smc_sec(u32 service, u32 proc_id, u32 flag, u32
*params);
*/
u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...);
+/*
+ * Invoke a secure ROM API on high-secure (HS) device variants that can be used
+ * to verify a secure blob by authenticating and optionally decrypting it. The
+ * exact operation performed depends on how the certificate that was embedded
+ * into the blob during the signing/encryption step when the secure blob was
+ * first created.
+ */
+int secure_boot_verify_image(void **p_image, size_t *p_size);
+
void enable_edma3_clocks(void);
void disable_edma3_clocks(void);
--
2.6.4
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