imx: HAB: Validate IVT before authenticating image

Calling csf_is_valid() with an un-signed image may lead to data abort
as the CSF pointer could be pointing to a garbage address when accessed
in HAB_HDR_LEN(*(const struct hab_hdr *)(ulong)ivt_initial->csf).

Authenticate image from DDR location 0x80800000...
Check CSF for Write Data command before authenticating image
data abort
pc : [<fff5494c>]          lr : [<fff54910>]
reloc pc : [<8780294c>]    lr : [<87802910>]
sp : fdf45dc8  ip : 00000214     fp : 00000000
r10: fffb6170  r9 : fdf4fec0     r8 : 00722020
r7 : 80f20000  r6 : 80800000     r5 : 80800000  r4 : 00720000
r3 : 17a5aca3  r2 : 00000000     r1 : 80f2201f  r0 : 00000019
Flags: NzcV  IRQs off  FIQs off  Mode SVC_32
Resetting CPU ...

resetting ...

To avoid such errors during authentication process, validate IVT structure
by calling validate_ivt function which checks the following values in an IVT:

IVT_HEADER = 0x4X2000D1
ENTRY != 0x0
RES1 = 0x0
DCD = 0x0       /* Recommended */
SELF != 0x0     /* Absoulute address of IVT */
CSF != 0x0
RES2 = 0x0

This commit also checks if Image's start address is 4 byte aligned.

commit "0088d127 MLK-14945 HAB: Check if IVT valid before authenticating image"
removed as this patch addresses the issue.

Signed-off-by: Utkarsh Gupta <utkarsh.gupta@nxp.com>
Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>

diff --git a/arch/arm/mach-imx/hab.c b/arch/arm/mach-imx/hab.c
index 9ebdbe6..f2d5f74 100644 (file)
--- a/arch/arm/mach-imx/hab.c
+++ b/arch/arm/mach-imx/hab.c
@@ -728,6 +728,48 @@ static bool csf_is_valid(struct ivt *ivt, ulong start_addr, size_t bytes)
        return true;
 }
 
+/*
+ * Validate IVT structure of the image being authenticated
+ */
+static int validate_ivt(struct ivt *ivt_initial)
+{
+       struct ivt_header *ivt_hdr = &ivt_initial->hdr;
+
+       if ((ulong)ivt_initial & 0x3) {
+               puts("Error: Image's start address is not 4 byte aligned\n");
+               return 0;
+       }
+
+       /* Check IVT fields before allowing authentication */
+       if ((!verify_ivt_header(ivt_hdr)) && \
+           (ivt_initial->entry != 0x0) && \
+           (ivt_initial->reserved1 == 0x0) && \
+           (ivt_initial->self == \
+                  (uint32_t)((ulong)ivt_initial & 0xffffffff)) && \
+           (ivt_initial->csf != 0x0) && \
+           (ivt_initial->reserved2 == 0x0)) {
+               /* Report boot failure if DCD pointer is found in IVT */
+               if (ivt_initial->dcd != 0x0)
+                       puts("Error: DCD pointer must be 0\n");
+               else
+                       return 1;
+       }
+
+       puts("Error: Invalid IVT structure\n");
+       debug("\nAllowed IVT structure:\n");
+       debug("IVT HDR       = 0x4X2000D1\n");
+       debug("IVT ENTRY     = 0xXXXXXXXX\n");
+       debug("IVT RSV1      = 0x0\n");
+       debug("IVT DCD       = 0x0\n");         /* Recommended */
+       debug("IVT BOOT_DATA = 0xXXXXXXXX\n");  /* Commonly 0x0 */
+       debug("IVT SELF      = 0xXXXXXXXX\n");  /* = ddr_start + ivt_offset */
+       debug("IVT CSF       = 0xXXXXXXXX\n");
+       debug("IVT RSV2      = 0x0\n");
+
+       /* Invalid IVT structure */
+       return 0;
+}
+
 bool imx_hab_is_enabled(void)
 {
        struct imx_sec_config_fuse_t *fuse =
@@ -753,7 +795,6 @@ int imx_hab_authenticate_image(uint32_t ddr_start, uint32_t image_size,
        int result = 1;
        ulong start;
        struct ivt *ivt;
-       struct ivt_header *ivt_hdr;
        enum hab_status status;
 
        if (!imx_hab_is_enabled()) {
@@ -769,24 +810,10 @@ int imx_hab_authenticate_image(uint32_t ddr_start, uint32_t image_size,
        /* Calculate IVT address header */
        ivt_addr = (ulong) (ddr_start + ivt_offset);
        ivt = (struct ivt *)ivt_addr;
-       ivt_hdr = &ivt->hdr;
 
        /* Verify IVT header bugging out on error */
-       if (verify_ivt_header(ivt_hdr))
-               goto hab_authentication_exit;
-
-       /* Verify IVT body */
-       if (ivt->self != ivt_addr) {
-               printf("ivt->self 0x%08x pointer is 0x%08lx\n",
-                      ivt->self, ivt_addr);
+       if (!validate_ivt(ivt))
                goto hab_authentication_exit;
-       }
-
-       /* Verify if IVT DCD pointer is NULL */
-       if (ivt->dcd) {
-               puts("Error: DCD pointer must be NULL\n");
-               goto hab_authentication_exit;
-       }
 
        start = ddr_start;
        bytes = image_size;