vboot: vb2_shared_data offsets should hang off parentstabilize-12428.B

vb2_shared_data struct has many offsets to other objects in the
workbuf.  They are all prefixed with `workbuf_`, e.g.:
  uint32_t workbuf_data_key_offset;
  uint32_t workbuf_data_key_size;

In order to adhere to a hierarchical structure on the workbuf,
remove the workbuf_ prefix from these symbols to reflect the
relationship between vb2_shared_data and its children more
accurately.

Create a helper function vb2_member_of to safely look up a child
of a particular object in the workbuf by offset.  Pointer
arithmetic to find vb2_shared_data children is replaced with
calls to this function.

BUG=b:124141368, chromium:994060
TEST=make clean && make runtests
BRANCH=none

Change-Id: Ia82417a35d2067ee5e4f42fea0396e6325127223
Signed-off-by: Joel Kitching <kitching@google.com>
Cq-Depend: chromium:1753400
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1718264
Commit-Queue: Joel Kitching <kitching@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 13 insertions, 13 deletions

diff --git a/firmware/lib20/kernel.c b/firmware/lib20/kernel.c
index 4d8f7721..10cf158f 100644
--- a/firmware/lib20/kernel.c
+++ b/firmware/lib20/kernel.c
@@ -121,8 +121,8 @@ vb2_error_t vb2_load_kernel_keyblock(struct vb2_context *ctx)
 	sd->flags &= ~VB2_SD_FLAG_KERNEL_SIGNED;
 
 	/* Unpack the kernel key */
-	key_data = ctx->workbuf + sd->workbuf_kernel_key_offset;
-	key_size = sd->workbuf_kernel_key_size;
+	key_data = vb2_member_of(sd, sd->kernel_key_offset);
+	key_size = sd->kernel_key_size;
 	rv = vb2_unpack_key_buffer(&kernel_key, key_data, key_size);
 	if (rv)
 		return rv;
@@ -217,8 +217,8 @@ vb2_error_t vb2_load_kernel_keyblock(struct vb2_context *ctx)
 	 * (which we might still need to verify the next kernel, if the
 	 * assoiciated kernel preamble and data don't verify).
 	 */
-	sd->workbuf_data_key_offset = ctx->workbuf_used;
-	key_data = ctx->workbuf + sd->workbuf_data_key_offset;
+	sd->data_key_offset = ctx->workbuf_used;
+	key_data = vb2_member_of(sd, sd->data_key_offset);
 	packed_key = (struct vb2_packed_key *)key_data;
 	memmove(packed_key, &kb->data_key, sizeof(*packed_key));
 	packed_key->key_offset = sizeof(*packed_key);
@@ -227,7 +227,7 @@ vb2_error_t vb2_load_kernel_keyblock(struct vb2_context *ctx)
 		packed_key->key_size);
 
 	/* Save the packed key size */
-	sd->workbuf_data_key_size =
+	sd->data_key_size =
 		packed_key->key_offset + packed_key->key_size;
 
 	/*
@@ -238,8 +238,8 @@ vb2_error_t vb2_load_kernel_keyblock(struct vb2_context *ctx)
 	 *   - kernel key
 	 *   - packed kernel data key
 	 */
-	vb2_set_workbuf_used(ctx, sd->workbuf_data_key_offset +
-			     sd->workbuf_data_key_size);
+	vb2_set_workbuf_used(ctx, sd->data_key_offset +
+			     sd->data_key_size);
 
 	return VB2_SUCCESS;
 }
@@ -357,8 +357,8 @@ vb2_error_t vb2_load_kernel_preamble(struct vb2_context *ctx)
 	struct vb2_shared_data *sd = vb2_get_sd(ctx);
 	struct vb2_workbuf wb;
 
-	uint8_t *key_data = ctx->workbuf + sd->workbuf_data_key_offset;
-	uint32_t key_size = sd->workbuf_data_key_size;
+	uint8_t *key_data = vb2_member_of(sd, sd->data_key_offset);
+	uint32_t key_size = sd->data_key_size;
 	struct vb2_public_key data_key;
 
 	/* Preamble goes in the next unused chunk of work buffer */
@@ -372,7 +372,7 @@ vb2_error_t vb2_load_kernel_preamble(struct vb2_context *ctx)
 	vb2_workbuf_from_ctx(ctx, &wb);
 
 	/* Unpack the kernel data key */
-	if (!sd->workbuf_data_key_size)
+	if (!sd->data_key_size)
 		return VB2_ERROR_KERNEL_PREAMBLE2_DATA_KEY;
 
 	rv = vb2_unpack_key_buffer(&data_key, key_data, key_size);
@@ -431,8 +431,8 @@ vb2_error_t vb2_load_kernel_preamble(struct vb2_context *ctx)
 		return VB2_ERROR_KERNEL_PREAMBLE_VERSION_ROLLBACK;
 
 	/* Keep track of where we put the preamble */
-	sd->workbuf_preamble_offset = vb2_offset_of(ctx->workbuf, pre);
-	sd->workbuf_preamble_size = pre_size;
+	sd->preamble_offset = vb2_offset_of(sd, pre);
+	sd->preamble_size = pre_size;
 
 	/*
 	 * Preamble will persist in work buffer after we return.
@@ -447,7 +447,7 @@ vb2_error_t vb2_load_kernel_preamble(struct vb2_context *ctx)
 	 * TODO: we could move the preamble down over the kernel data key
 	 * since we don't need it anymore.
 	 */
-	vb2_set_workbuf_used(ctx, sd->workbuf_preamble_offset + pre_size);
+	vb2_set_workbuf_used(ctx, sd->preamble_offset + pre_size);
 
 	return VB2_SUCCESS;
 }