| /* Copyright (c) 2014 The Chromium OS Authors. All rights reserved. |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| * |
| * Common functions between firmware and kernel verified boot. |
| * (Firmware portion) |
| */ |
| |
| #include "2sysincludes.h" |
| #include "2common.h" |
| #include "2rsa.h" |
| #include "2sha.h" |
| |
| int vb2_safe_memcmp(const void *s1, const void *s2, size_t size) |
| { |
| const unsigned char *us1 = s1; |
| const unsigned char *us2 = s2; |
| int result = 0; |
| |
| if (0 == size) |
| return 0; |
| |
| /* |
| * Code snippet without data-dependent branch due to Nate Lawson |
| * (nate@root.org) of Root Labs. |
| */ |
| while (size--) |
| result |= *us1++ ^ *us2++; |
| |
| return result != 0; |
| } |
| |
| int vb2_align(uint8_t **ptr, uint32_t *size, uint32_t align, uint32_t want_size) |
| { |
| uintptr_t p = (uintptr_t)*ptr; |
| uintptr_t offs = p & (align - 1); |
| |
| if (offs) { |
| offs = align - offs; |
| |
| if (*size < offs) |
| return VB2_ERROR_ALIGN_BIGGER_THAN_SIZE; |
| |
| *ptr += offs; |
| *size -= offs; |
| } |
| |
| if (*size < want_size) |
| return VB2_ERROR_ALIGN_SIZE; |
| |
| return VB2_SUCCESS; |
| } |
| |
| void vb2_workbuf_init(struct vb2_workbuf *wb, uint8_t *buf, uint32_t size) |
| { |
| wb->buf = buf; |
| wb->size = size; |
| |
| /* Align the buffer so allocations will be aligned */ |
| if (vb2_align(&wb->buf, &wb->size, VB2_WORKBUF_ALIGN, 0)) |
| wb->size = 0; |
| } |
| |
| void *vb2_workbuf_alloc(struct vb2_workbuf *wb, uint32_t size) |
| { |
| uint8_t *ptr = wb->buf; |
| |
| /* Round up size to work buffer alignment */ |
| size = vb2_wb_round_up(size); |
| |
| if (size > wb->size) |
| return NULL; |
| |
| wb->buf += size; |
| wb->size -= size; |
| |
| return ptr; |
| } |
| |
| void *vb2_workbuf_realloc(struct vb2_workbuf *wb, |
| uint32_t oldsize, |
| uint32_t newsize) |
| { |
| /* |
| * Just free and allocate to update the size. No need to move/copy |
| * memory, since the new pointer is guaranteed to be the same as the |
| * old one. The new allocation can fail, if the new size is too big. |
| */ |
| vb2_workbuf_free(wb, oldsize); |
| return vb2_workbuf_alloc(wb, newsize); |
| } |
| |
| void vb2_workbuf_free(struct vb2_workbuf *wb, uint32_t size) |
| { |
| /* Round up size to work buffer alignment */ |
| size = vb2_wb_round_up(size); |
| |
| wb->buf -= size; |
| wb->size += size; |
| } |
| |
| ptrdiff_t vb2_offset_of(const void *base, const void *ptr) |
| { |
| return (uintptr_t)ptr - (uintptr_t)base; |
| } |