From: Andre Noll <maan@tuebingen.mpg.de>
Date: Thu, 28 Dec 2017 00:41:14 +0000 (+0100)
Subject: crypt: Deduplicate get_public_key().
X-Git-Tag: v0.6.2~5^2~5
X-Git-Url: https://git.tuebingen.mpg.de/?a=commitdiff_plain;h=5f20d9afde364f9ce51aa7841ebe513028a65e81;p=paraslash.git
crypt: Deduplicate get_public_key().
The openssl and grypt implementations of this function share quite
some code. This patch factors out the common code into the new
decode_ssh_key() helper of crypt_common.c. Both implementations are
changed to call the new helper.
As a side effect of this change, all callers of is_ssh_rsa_key()
and check_ssh_key_header() now reside in crypt_common.c, so we can
make these two functions static and remove their declarations from
crypt_backend.h.
---
diff --git a/crypt_backend.h b/crypt_backend.h
index ff956ce3..175a6881 100644
--- a/crypt_backend.h
+++ b/crypt_backend.h
@@ -7,6 +7,6 @@
/** AES block size in bytes. */
#define AES_CRT128_BLOCK_SIZE 16
-size_t is_ssh_rsa_key(char *data, size_t size);
-int check_ssh_key_header(const unsigned char *blob, int blen);
+int decode_ssh_key(const char *filename, unsigned char **blob,
+ size_t *decoded_size);
int check_private_key_file(const char *file);
diff --git a/crypt_common.c b/crypt_common.c
index 08361b27..235b8b8d 100644
--- a/crypt_common.c
+++ b/crypt_common.c
@@ -10,20 +10,19 @@
#include "crypt.h"
#include "crypt_backend.h"
#include "portable_io.h"
+#include "fd.h"
+#include "base64.h"
/** If the key begins with this text, we treat it as an ssh key. */
#define KEY_TYPE_TXT "ssh-rsa"
-/**
- * Check if given buffer starts with a ssh rsa key signature.
- *
- * \param data The buffer.
- * \param size Number of data bytes.
+/*
+ * Check if the given buffer starts with an ssh rsa key signature.
*
- * \return Number of header bytes to be skipped on success, zero if
- * ssh rsa signature was not found.
+ * Returns number of header bytes to be skipped on success, zero if no ssh rsa
+ * signature was found.
*/
-size_t is_ssh_rsa_key(char *data, size_t size)
+static size_t is_ssh_rsa_key(char *data, size_t size)
{
char *cp;
@@ -42,20 +41,13 @@ size_t is_ssh_rsa_key(char *data, size_t size)
return cp - data;
}
-/**
- * Sanity checks for the header of an ssh key.
- *
- * \param blob The buffer.
- * \param blen The number of bytes of \a blob.
+/*
+ * Perform some sanity checks on the decoded ssh key.
*
- * This performs some checks to make sure we really have an ssh key. It also
- * computes the offset in bytes of the start of the key values (modulus,
- * exponent..).
- *
- * \return The number of bytes to skip until the start of the first encoded
- * number (usually 11).
+ * This function returns the size of the header. Usually, the header is 11
+ * bytes long: four bytes for the length field, and the string "ssh-rsa".
*/
-int check_ssh_key_header(const unsigned char *blob, int blen)
+static int check_ssh_key_header(const unsigned char *blob, int blen)
{
const unsigned char *p = blob, *end = blob + blen;
uint32_t rlen;
@@ -76,6 +68,51 @@ int check_ssh_key_header(const unsigned char *blob, int blen)
return 4 + rlen;
}
+/**
+ * Perform sanity checks and base64-decode an ssh-rsa key.
+ *
+ * \param filename The public key file (usually id_rsa.pub).
+ * \param blob Pointer to base64-decoded blob is returned here.
+ * \param decoded_size The size of the decoded blob.
+ *
+ * The memory pointed at by the returned blob pointer has to be freed by the
+ * caller.
+ *
+ * \return On success, the offset in bytes of the start of the key values
+ * (modulus, exponent..). This is the number of bytes to skip from the blob
+ * until the start of the first encoded number. On failure, a negative error
+ * code is returned.
+ *
+ * \sa \ref uudecode().
+ */
+int decode_ssh_key(const char *filename, unsigned char **blob,
+ size_t *decoded_size)
+{
+ int ret, ret2;
+ void *map;
+ size_t map_size;
+
+ ret = mmap_full_file(filename, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ return ret;
+ ret = is_ssh_rsa_key(map, map_size);
+ if (ret == 0) {
+ ret = -E_SSH_PARSE;
+ goto unmap;
+ }
+ ret = uudecode(map + ret, map_size - ret, (char **)blob, decoded_size);
+ if (ret < 0)
+ goto unmap;
+ ret = check_ssh_key_header(*blob, *decoded_size);
+ if (ret < 0)
+ goto unmap;
+unmap:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ return ret;
+}
+
/**
* Check existence and permissions of a private key file.
*
diff --git a/gcrypt.c b/gcrypt.c
index 052546dd..2398a605 100644
--- a/gcrypt.c
+++ b/gcrypt.c
@@ -366,27 +366,21 @@ free_blob:
return ret;
}
-static int get_ssh_public_key(unsigned char *data, int size, gcry_sexp_t *result)
+int get_public_key(const char *key_file, struct asymmetric_key **result)
{
+ unsigned char *blob, *p, *end;
int ret;
gcry_error_t gret;
- unsigned char *blob = NULL, *p, *end;
size_t nr_scanned, erroff, decoded_size;
- gcry_mpi_t e = NULL, n = NULL;
+ gcry_mpi_t e, n;
+ gcry_sexp_t sexp;
+ struct asymmetric_key *key;
- PARA_DEBUG_LOG("decoding %d byte public rsa-ssh key\n", size);
- ret = uudecode((char *)data, size, (char **)&blob, &decoded_size);
- if (ret < 0)
- goto free_blob;
- end = blob + decoded_size;
- dump_buffer("decoded key", blob, decoded_size);
- ret = check_ssh_key_header(blob, decoded_size);
+ ret = decode_ssh_key(key_file, &blob, &decoded_size);
if (ret < 0)
- goto free_blob;
+ return ret;
p = blob + ret;
- ret = -E_SSH_PARSE;
- if (p >= end)
- goto free_blob;
+ end = blob + decoded_size;
PARA_DEBUG_LOG("scanning modulus and public exponent\n");
gret = gcry_mpi_scan(&e, GCRYMPI_FMT_SSH, p, end - p, &nr_scanned);
if (gret) {
@@ -395,8 +389,6 @@ static int get_ssh_public_key(unsigned char *data, int size, gcry_sexp_t *result
goto free_blob;
}
PARA_DEBUG_LOG("scanned e (%zu bytes)\n", nr_scanned);
-// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, rsa_e);
-// PARA_CRIT_LOG("e: %s\n", buf);
p += nr_scanned;
if (p >= end)
goto release_e;
@@ -407,9 +399,7 @@ static int get_ssh_public_key(unsigned char *data, int size, gcry_sexp_t *result
goto release_e;
}
PARA_DEBUG_LOG("scanned n (%zu bytes)\n", nr_scanned);
-// gcry_mpi_aprint(GCRYMPI_FMT_HEX, &buf, NULL, rsa_n);
-// PARA_CRIT_LOG("n: %s\n", buf);
- gret = gcry_sexp_build(result, &erroff, RSA_PUBKEY_SEXP, n, e);
+ gret = gcry_sexp_build(&sexp, &erroff, RSA_PUBKEY_SEXP, n, e);
if (gret) {
PARA_ERROR_LOG("offset %zu: %s\n", erroff,
gcry_strerror(gcry_err_code(gret)));
@@ -418,6 +408,10 @@ static int get_ssh_public_key(unsigned char *data, int size, gcry_sexp_t *result
}
ret = nr_scanned / 32 * 32;
PARA_INFO_LOG("successfully read %d bit ssh public key\n", ret * 8);
+ key = para_malloc(sizeof(*key));
+ key->num_bytes = ret;
+ key->sexp = sexp;
+ *result = key;
release_n:
gcry_mpi_release(n);
release_e:
@@ -427,42 +421,6 @@ free_blob:
return ret;
}
-int get_public_key(const char *key_file, struct asymmetric_key **result)
-{
- int ret, ret2;
- void *map;
- size_t map_size;
- unsigned char *start, *end;
- gcry_sexp_t sexp;
- struct asymmetric_key *key;
-
- ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
- if (ret < 0)
- return ret;
- ret = is_ssh_rsa_key(map, map_size);
- if (!ret) {
- para_munmap(map, map_size);
- return -E_SSH_PARSE;
- }
- start = map + ret;
- end = map + map_size;
- ret = -E_SSH_PARSE;
- if (start >= end)
- goto unmap;
- ret = get_ssh_public_key(start, end - start, &sexp);
- if (ret < 0)
- goto unmap;
- key = para_malloc(sizeof(*key));
- key->num_bytes = ret;
- key->sexp = sexp;
- *result = key;
-unmap:
- ret2 = para_munmap(map, map_size);
- if (ret >= 0 && ret2 < 0)
- ret = ret2;
- return ret;
-}
-
void free_public_key(struct asymmetric_key *key)
{
if (!key)
diff --git a/openssl.c b/openssl.c
index f786ce29..99b3f7a6 100644
--- a/openssl.c
+++ b/openssl.c
@@ -16,9 +16,7 @@
#include "error.h"
#include "string.h"
#include "crypt.h"
-#include "fd.h"
#include "crypt_backend.h"
-#include "base64.h"
#include "portable_io.h"
struct asymmetric_key {
@@ -45,7 +43,7 @@ void get_random_bytes_or_die(unsigned char *buf, int num)
* \sa RAND_load_file(3), \ref get_random_bytes_or_die(), srandom(3),
* random(3), \ref para_random().
*/
-void init_random_seed_or_die(void)
+void crypt_init(void)
{
int seed, ret = RAND_load_file("/dev/urandom", 64);
@@ -141,47 +139,28 @@ fail:
int get_public_key(const char *key_file, struct asymmetric_key **result)
{
- struct asymmetric_key *key = NULL;
- void *map = NULL;
- unsigned char *blob = NULL;
- size_t map_size, encoded_size, decoded_size;
- int ret, ret2;
- char *cp;
+ unsigned char *blob;
+ size_t decoded_size;
+ int ret;
+ struct asymmetric_key *key = para_malloc(sizeof(*key));
- key = para_malloc(sizeof(*key));
- ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ ret = decode_ssh_key(key_file, &blob, &decoded_size);
if (ret < 0)
goto out;
- ret = is_ssh_rsa_key(map, map_size);
- if (!ret) {
- ret = -E_SSH_PARSE;
- goto out_unmap;
- }
- cp = map + ret;
- encoded_size = map_size - ret;
- PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file);
- ret = uudecode(cp, encoded_size, (char **)&blob, &decoded_size);
- if (ret < 0)
- goto out_unmap;
- ret = check_ssh_key_header(blob, decoded_size);
- if (ret < 0)
- goto out_unmap;
ret = read_rsa_bignums(blob + ret, decoded_size - ret, &key->rsa);
if (ret < 0)
- goto out_unmap;
+ goto free_blob;
ret = RSA_size(key->rsa);
-out_unmap:
- ret2 = para_munmap(map, map_size);
- if (ret >= 0 && ret2 < 0)
- ret = ret2;
+ assert(ret > 0);
+ *result = key;
+free_blob:
+ free(blob);
out:
if (ret < 0) {
free(key);
*result = NULL;
- PARA_ERROR_LOG("key %s: %s\n", key_file, para_strerror(-ret));
- } else
- *result = key;
- free(blob);
+ PARA_ERROR_LOG("can not load key %s\n", key_file);
+ }
return ret;
}