From: Jes Sorensen <jsorensen@xxxxxx>
This preps the code for splitting the signing into the shared library
Signed-off-by: Jes Sorensen <jsorensen@xxxxxx>
---
cmd_sign.c | 48 +++++++++++++++++++++++++++++++++++++-----------
fsverity.c | 1 +
libfsverity.h | 41 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 79 insertions(+), 11 deletions(-)
create mode 100644 libfsverity.h
diff --git a/cmd_sign.c b/cmd_sign.c
index dcb37ce..dcc44f8 100644
--- a/cmd_sign.c
+++ b/cmd_sign.c
@@ -16,6 +16,8 @@
#include <openssl/pkcs7.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
#include "commands.h"
#include "fsverity_uapi.h"
@@ -382,11 +384,30 @@ static bool hash_one_block(struct hash_ctx *hash, struct block_buffer *cur,
return next->filled + hash->alg->digest_size > block_size;
}
+static int full_read_fd(int fd, void *buf, size_t count)
+{
+ while (count) {
+ int n = read(fd, buf, min(count, INT_MAX));
+
+ if (n < 0) {
+ error_msg_errno("reading from file");
+ return n;
+ }
+ if (n == 0) {
+ error_msg("unexpected end-of-file");
+ return -ENODATA;
+ }
+ buf += n;
+ count -= n;
+ }
+ return 0;
+}
+
/*
* Compute the file's Merkle tree root hash using the given hash algorithm,
* block size, and salt.
*/
-static bool compute_root_hash(struct filedes *file, u64 file_size,
+static bool compute_root_hash(int fd, u64 file_size,
struct hash_ctx *hash, u32 block_size,
const u8 *salt, u32 salt_size, u8 *root_hash)
{
@@ -424,7 +445,7 @@ static bool compute_root_hash(struct filedes *file, u64 file_size,
for (offset = 0; offset < file_size; offset += block_size) {
buffers[-1].filled = min(block_size, file_size - offset);
- if (!full_read(file, buffers[-1].data, buffers[-1].filled))
+ if (full_read_fd(fd, buffers[-1].data, buffers[-1].filled))
goto out;
level = -1;
@@ -457,22 +478,22 @@ out:
* The fs-verity measurement is the hash of the fsverity_descriptor, which
* contains the Merkle tree properties including the root hash.
*/
-static bool compute_file_measurement(const char *filename,
+static bool compute_file_measurement(int fd,
const struct fsverity_hash_alg *hash_alg,
u32 block_size, const u8 *salt,
u32 salt_size, u8 *measurement)
{
- struct filedes file = { .fd = -1 };
struct hash_ctx *hash = hash_create(hash_alg);
u64 file_size;
struct fsverity_descriptor desc;
+ struct stat stbuf;
bool ok = false;
- if (!open_file(&file, filename, O_RDONLY, 0))
- goto out;
-
- if (!get_file_size(&file, &file_size))
+ if (fstat(fd, &stbuf) != 0) {
+ error_msg_errno("can't stat input file");
goto out;
+ }
+ file_size = stbuf.st_size;
memset(&desc, 0, sizeof(desc));
desc.version = 1;
@@ -495,14 +516,13 @@ static bool compute_file_measurement(const char *filename,
/* Root hash of empty file is all 0's */
if (file_size != 0 &&
- !compute_root_hash(&file, file_size, hash, block_size, salt,
+ !compute_root_hash(fd, file_size, hash, block_size, salt,
salt_size, desc.root_hash))
goto out;
hash_full(hash, &desc, sizeof(desc), measurement);
ok = true;
out:
- filedes_close(&file);
hash_free(hash);
return ok;
}
@@ -529,6 +549,7 @@ int fsverity_cmd_sign(const struct fsverity_command *cmd,
int argc, char *argv[])
{
const struct fsverity_hash_alg *hash_alg = NULL;
+ struct filedes file = { .fd = -1 };
u32 block_size = 0;
u8 *salt = NULL;
u32 salt_size = 0;
@@ -603,10 +624,15 @@ int fsverity_cmd_sign(const struct fsverity_command *cmd,
digest->digest_algorithm = cpu_to_le16(hash_alg - fsverity_hash_algs);
digest->digest_size = cpu_to_le16(hash_alg->digest_size);
- if (!compute_file_measurement(argv[0], hash_alg, block_size,
+ if (!open_file(&file, argv[0], O_RDONLY, 0))
+ goto out_err;
+
+ if (!compute_file_measurement(file.fd, hash_alg, block_size,
salt, salt_size, digest->digest))
goto out_err;
+ filedes_close(&file);
+
if (!sign_data(digest, sizeof(*digest) + hash_alg->digest_size,
keyfile, certfile, hash_alg, &sig, &sig_size))
goto out_err;
diff --git a/fsverity.c b/fsverity.c
index 9a44df1..c8fa1b5 100644
--- a/fsverity.c
+++ b/fsverity.c
@@ -14,6 +14,7 @@
#include "commands.h"
#include "hash_algs.h"
+#include "libfsverity.h"
static const struct fsverity_command {
const char *name;
diff --git a/libfsverity.h b/libfsverity.h
new file mode 100644
index 0000000..ceebae1
--- /dev/null
+++ b/libfsverity.h
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * libfsverity API
+ *
+ * Copyright (C) 2018 Google LLC
+ * Copyright (C) 2020 Facebook
+ *
+ * Written by Eric Biggers and modified by Jes Sorensen.
+ */
+
+#ifndef _LIBFSVERITY_H
+#define _LIBFSVERITY_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define FS_VERITY_HASH_ALG_SHA256 1
+#define FS_VERITY_HASH_ALG_SHA512 2
+
+struct libfsverity_merkle_tree_params {
+ uint16_t version;
+ uint16_t hash_algorithm;
+ uint32_t block_size;
+ uint32_t salt_size;
+ const uint8_t *salt;
+ uint64_t reserved[11];
+};
+
+struct libfsverity_digest {
+ uint16_t digest_algorithm;
+ uint16_t digest_size;
+ uint8_t digest[];
+};
+
+struct libfsverity_signature_params {
+ const char *keyfile;
+ const char *certfile;
+ uint64_t reserved[11];
+};
+
+#endif
--
2.25.3
|