[PATCH 2/4] add signing option -O hashalg=algorithm
Linus Nordberg
linus at nordberg.se
Wed Dec 22 19:23:37 AEDT 2021
---
ssh-keygen.1 | 4 ++++
ssh-keygen.c | 36 ++++++++++++++++++++++++------------
2 files changed, 28 insertions(+), 12 deletions(-)
diff --git a/ssh-keygen.1 b/ssh-keygen.1
index 58b1f682..f0f211c4 100644
--- a/ssh-keygen.1
+++ b/ssh-keygen.1
@@ -161,6 +161,7 @@
.Fl s Ar signature_file
.Nm ssh-keygen
.Fl Y Cm sign
+.Op Fl O Ar option
.Fl f Ar key_file
.Fl n Ar namespace
.Ar
@@ -541,6 +542,9 @@ When performing signature-related options using the
.Fl Y
flag, the following options are accepted:
.Bl -tag -width Ds
+.It Cm hashalg Ns = Ns Ar algorithm
+Selects the hash algorithm to use for hashing the message to be signed.
+Valid algorithms are sha256 and sha512. The default is sha512.
.It Cm print-pubkey
Print the full public key to standard output after signature verification.
.It Cm verify-time Ns = Ns Ar timestamp
diff --git a/ssh-keygen.c b/ssh-keygen.c
index d31dc503..ef99b9b6 100644
--- a/ssh-keygen.c
+++ b/ssh-keygen.c
@@ -142,6 +142,9 @@ struct cert_ext {
static struct cert_ext *cert_ext;
static size_t ncert_ext;
+/* Default hash algorithm for -Y sign and verify. */
+#define DEFAULT_SIGN_HASHALG_NAME "sha512"
+
/* Conversion to/from various formats */
enum {
FMT_RFC4716,
@@ -2512,7 +2515,7 @@ load_sign_key(const char *keypath, const struct sshkey *pubkey)
static int
sign_one(struct sshkey *signkey, const char *filename, int fd,
- const char *sig_namespace, sshsig_signer *signer, void *signer_ctx)
+ const char *sig_namespace, const char *hashalg, sshsig_signer *signer, void *signer_ctx)
{
struct sshbuf *sigbuf = NULL, *abuf = NULL;
int r = SSH_ERR_INTERNAL_ERROR, wfd = -1, oerrno;
@@ -2542,7 +2545,7 @@ sign_one(struct sshkey *signkey, const char *filename, int fd,
free(fp);
}
}
- if ((r = sshsig_sign_fd(signkey, NULL, sk_provider, pin,
+ if ((r = sshsig_sign_fd(signkey, hashalg, sk_provider, pin,
fd, sig_namespace, &sigbuf, signer, signer_ctx)) != 0) {
error_r(r, "Signing %s failed", filename);
goto out;
@@ -2603,18 +2606,23 @@ sign_one(struct sshkey *signkey, const char *filename, int fd,
}
static int
-sig_process_opts(char * const *opts, size_t nopts, uint64_t *verify_timep,
+sig_process_opts(char * const *opts, size_t nopts, char *hashalg, size_t hashalg_size, uint64_t *verify_timep,
int *print_pubkey)
{
size_t i;
time_t now;
+ if (hashalg != NULL)
+ strlcpy(hashalg, DEFAULT_SIGN_HASHALG_NAME, hashalg_size);
if (verify_timep != NULL)
*verify_timep = 0;
if (print_pubkey != NULL)
*print_pubkey = 0;
for (i = 0; i < nopts; i++) {
- if (verify_timep &&
+ if (hashalg &&
+ strncasecmp(opts[i], "hashalg=", 8) == 0) {
+ strlcpy(hashalg, opts[i] + 8, hashalg_size);
+ } else if (verify_timep &&
strncasecmp(opts[i], "verify-time=", 12) == 0) {
if (parse_absolute_time(opts[i] + 12,
verify_timep) != 0 || *verify_timep == 0) {
@@ -2640,12 +2648,13 @@ sig_process_opts(char * const *opts, size_t nopts, uint64_t *verify_timep,
}
static int
-sig_sign(const char *keypath, const char *sig_namespace, int argc, char **argv)
+sig_sign(const char *keypath, const char *sig_namespace, int argc, char **argv, char * const *opts, size_t nopts)
{
int i, fd = -1, r, ret = -1;
int agent_fd = -1;
struct sshkey *pubkey = NULL, *privkey = NULL, *signkey = NULL;
sshsig_signer *signer = NULL;
+ char hashalg[7]; /* "shaXXX" */
/* Check file arguments. */
for (i = 0; i < argc; i++) {
@@ -2655,6 +2664,9 @@ sig_sign(const char *keypath, const char *sig_namespace, int argc, char **argv)
fatal("Cannot sign mix of paths and standard input");
}
+ if (sig_process_opts(opts, nopts, hashalg, sizeof(hashalg), NULL, NULL) != 0)
+ goto done; /* error already logged */
+
if ((r = sshkey_load_public(keypath, &pubkey, NULL)) != 0) {
error_r(r, "Couldn't load public key %s", keypath);
goto done;
@@ -2681,7 +2693,7 @@ sig_sign(const char *keypath, const char *sig_namespace, int argc, char **argv)
if (argc == 0) {
if ((r = sign_one(signkey, "(stdin)", STDIN_FILENO,
- sig_namespace, signer, &agent_fd)) != 0)
+ sig_namespace, hashalg, signer, &agent_fd)) != 0)
goto done;
} else {
for (i = 0; i < argc; i++) {
@@ -2693,7 +2705,7 @@ sig_sign(const char *keypath, const char *sig_namespace, int argc, char **argv)
goto done;
}
if ((r = sign_one(signkey, argv[i], fd, sig_namespace,
- signer, &agent_fd)) != 0)
+ hashalg, signer, &agent_fd)) != 0)
goto done;
if (fd != STDIN_FILENO)
close(fd);
@@ -2723,7 +2735,7 @@ sig_verify(const char *signature, const char *sig_namespace,
struct sshkey_sig_details *sig_details = NULL;
uint64_t verify_time = 0;
- if (sig_process_opts(opts, nopts, &verify_time, &print_pubkey) != 0)
+ if (sig_process_opts(opts, nopts, NULL, 0, &verify_time, &print_pubkey) != 0)
goto done; /* error already logged */
memset(&sig_details, 0, sizeof(sig_details));
@@ -2811,7 +2823,7 @@ sig_find_principals(const char *signature, const char *allowed_keys,
char *principals = NULL, *cp, *tmp;
uint64_t verify_time = 0;
- if (sig_process_opts(opts, nopts, &verify_time, NULL) != 0)
+ if (sig_process_opts(opts, nopts, NULL, 0, &verify_time, NULL) != 0)
goto done; /* error already logged */
if ((r = sshbuf_load_file(signature, &abuf)) != 0) {
@@ -2857,7 +2869,7 @@ sig_match_principals(const char *allowed_keys, char *principal,
char **principals = NULL;
size_t i, nprincipals = 0;
- if ((r = sig_process_opts(opts, nopts, NULL, NULL)) != 0)
+ if ((r = sig_process_opts(opts, nopts, NULL, 0, NULL, NULL)) != 0)
return r; /* error already logged */
if ((r = sshsig_match_principals(allowed_keys, principal,
@@ -3215,7 +3227,7 @@ usage(void)
" ssh-keygen -Y find-principals -s signature_file -f allowed_signers_file\n"
" ssh-keygen -Y match-principals -I signer_identity -f allowed_signers_file\n"
" ssh-keygen -Y check-novalidate -n namespace -s signature_file\n"
- " ssh-keygen -Y sign -f key_file -n namespace file ...\n"
+ " ssh-keygen -Y sign -f key_file -n namespace file [-O option] ...\n"
" ssh-keygen -Y verify -f allowed_signers_file -I signer_identity\n"
" -n namespace -s signature_file [-r revocation_file]\n");
exit(1);
@@ -3521,7 +3533,7 @@ main(int argc, char **argv)
exit(1);
}
return sig_sign(identity_file, cert_principals,
- argc, argv);
+ argc, argv, opts, nopts);
} else if (strncmp(sign_op, "check-novalidate", 16) == 0) {
if (ca_key_path == NULL) {
error("Too few arguments for check-novalidate: "
--
2.30.2
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