diff options
Diffstat (limited to 'firmware/2lib')
-rw-r--r-- | firmware/2lib/2common.c | 39 | ||||
-rw-r--r-- | firmware/2lib/2packed_key.c | 22 | ||||
-rw-r--r-- | firmware/2lib/include/2common.h | 47 | ||||
-rw-r--r-- | firmware/2lib/include/2struct.h | 34 |
4 files changed, 140 insertions, 2 deletions
diff --git a/firmware/2lib/2common.c b/firmware/2lib/2common.c index 4db9e77a..472d5acc 100644 --- a/firmware/2lib/2common.c +++ b/firmware/2lib/2common.c @@ -103,3 +103,42 @@ ptrdiff_t vb2_offset_of(const void *base, const void *ptr) { return (uintptr_t)ptr - (uintptr_t)base; } + +int vb2_verify_member_inside(const void *parent, size_t parent_size, + const void *member, size_t member_size, + ptrdiff_t member_data_offset, + size_t member_data_size) +{ + const uintptr_t parent_end = (uintptr_t)parent + parent_size; + const ptrdiff_t member_offs = vb2_offset_of(parent, member); + const ptrdiff_t member_end_offs = member_offs + member_size; + const ptrdiff_t data_offs = member_offs + member_data_offset; + const ptrdiff_t data_end_offs = data_offs + member_data_size; + + /* Make sure parent doesn't wrap */ + if (parent_end < (uintptr_t)parent) + return VB2_ERROR_INSIDE_PARENT_WRAPS; + + /* + * Make sure the member is fully contained in the parent and doesn't + * wrap. Use >, not >=, since member_size = 0 is possible. + */ + if (member_end_offs < member_offs) + return VB2_ERROR_INSIDE_MEMBER_WRAPS; + if (member_offs < 0 || member_offs > parent_size || + member_end_offs > parent_size) + return VB2_ERROR_INSIDE_MEMBER_OUTSIDE; + + /* Make sure the member data is after the member */ + if (member_data_size > 0 && data_offs < member_end_offs) + return VB2_ERROR_INSIDE_DATA_OVERLAP; + + /* Make sure parent fully contains member data, if any */ + if (data_end_offs < data_offs) + return VB2_ERROR_INSIDE_DATA_WRAPS; + if (data_offs < 0 || data_offs > parent_size || + data_end_offs > parent_size) + return VB2_ERROR_INSIDE_DATA_OUTSIDE; + + return VB2_SUCCESS; +} diff --git a/firmware/2lib/2packed_key.c b/firmware/2lib/2packed_key.c new file mode 100644 index 00000000..00262866 --- /dev/null +++ b/firmware/2lib/2packed_key.c @@ -0,0 +1,22 @@ +/* Copyright 2019 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. + * + * Packed key related functions. + */ + +#include "2common.h" + +const uint8_t *vb2_packed_key_data(const struct vb2_packed_key *key) +{ + return (const uint8_t *)key + key->key_offset; +} + +int vb2_verify_packed_key_inside(const void *parent, + uint32_t parent_size, + const struct vb2_packed_key *key) +{ + return vb2_verify_member_inside(parent, parent_size, + key, sizeof(*key), + key->key_offset, key->key_size); +} diff --git a/firmware/2lib/include/2common.h b/firmware/2lib/include/2common.h index 4b80e12c..be8a4ec5 100644 --- a/firmware/2lib/include/2common.h +++ b/firmware/2lib/include/2common.h @@ -200,4 +200,51 @@ const struct vb2_id *vb2_hash_id(enum vb2_hash_algorithm hash_alg); */ #define VB2_VERIFY_KERNEL_PREAMBLE_WORKBUF_BYTES VB2_VERIFY_DATA_WORKBUF_BYTES +/** + * Verify the data pointed to by a subfield is inside the parent data. + * + * The subfield has a header pointed to by member, and a separate data + * field at an offset relative to the header. That is: + * + * struct parent { + * (possibly other parent fields) + * struct member { + * (member header fields) + * }; + * (possibly other parent fields) + * }; + * (possibly some other parent data) + * (member data) + * (possibly some other parent data) + * + * @param parent Parent data + * @param parent_size Parent size in bytes + * @param member Subfield header + * @param member_size Size of subfield header in bytes + * @param member_data_offset Offset of member data from start of member + * @param member_data_size Size of member data in bytes + * @return VB2_SUCCESS, or non-zero if error. + */ +int vb2_verify_member_inside(const void *parent, size_t parent_size, + const void *member, size_t member_size, + ptrdiff_t member_data_offset, + size_t member_data_size); + +/* + * Helper function to get data pointed to by a public key. + */ +const uint8_t *vb2_packed_key_data(const struct vb2_packed_key *key); + +/** + * Verify a packed key is fully contained in its parent data + * + * @param parent Parent data + * @param parent_size Parent size in bytes + * @param key Packed key pointer + * @return VB2_SUCCESS, or non-zero if error. + */ +int vb2_verify_packed_key_inside(const void *parent, + uint32_t parent_size, + const struct vb2_packed_key *key); + #endif /* VBOOT_REFERENCE_VBOOT_2COMMON_H_ */ diff --git a/firmware/2lib/include/2struct.h b/firmware/2lib/include/2struct.h index 0b94c20a..2ca30142 100644 --- a/firmware/2lib/include/2struct.h +++ b/firmware/2lib/include/2struct.h @@ -2,8 +2,15 @@ * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. * - * Data structure definitions for verified boot, for on-disk / in-eeprom - * data. + * Vboot data structures. + * + * Note: Many of the structs have pairs of 32-bit fields and reserved fields. + * This is to be backwards-compatible with older verified boot data which used + * 64-bit fields (when we thought that hey, UEFI is 64-bit so all our fields + * should be too). + * + * Offsets should be padded to 32-bit boundaries, since some architectures + * have trouble with accessing unaligned integers. */ #ifndef VBOOT_REFERENCE_VBOOT_2STRUCT_H_ @@ -301,4 +308,27 @@ struct vb2_ryu_root_key_hash { #define EXPECTED_VB2_RYU_ROOT_KEY_HASH_SIZE 48 +/* Packed public key data */ +struct vb2_packed_key { + /* Offset of key data from start of this struct */ + uint32_t key_offset; + uint32_t reserved0; + + /* Size of key data in bytes (NOT strength of key in bits) */ + uint32_t key_size; + uint32_t reserved1; + + /* Signature algorithm used by the key (enum vb2_crypto_algorithm) */ + uint32_t algorithm; + uint32_t reserved2; + + /* Key version */ + uint32_t key_version; + uint32_t reserved3; + + /* TODO: when redoing this struct, add a text description of the key */ +} __attribute__((packed)); + +#define EXPECTED_VB2_PACKED_KEY_SIZE 32 + #endif /* VBOOT_REFERENCE_VBOOT_2STRUCT_H_ */ |