Verify key fingerprints.

diff --git a/key.1 b/key.1
index 07237a7..785021e 100644 (file)
--- a/key.1
+++ b/key.1
@@ -117,6 +117,14 @@ is one of:
 .IR hash ]
 .RI [ tag ...]
 .br
+.B verify
+.RB [ \-f
+.IR filter ]
+.RB [ \-a
+.IR hash ]
+.I tag
+.I fingerprint
+.br
 .B tidy
 .br
 .B extract
@@ -301,7 +309,9 @@ command.
 .B hash
 The hash functions which can be used with the
 .B fingerprint
-command.
+and
+.B verify
+commands.
 .TP
 .B ec
 The built-in elliptic curves which can be used with the
@@ -613,7 +623,7 @@ Finally, the
 option can be given, in which case the parameters are taken directly
 from the provided group specification, which may either be the the name
 of one of the built-in groups (say
-.B "key add \-a dh\-param \-C list 42"
+.B "key show dh"
 for a list) or a triple
 .RI ( p ,\  q ,\  g ).
 separated by commas.  No random generation is done in this case: the
@@ -715,7 +725,7 @@ A
 can be given explicitly (in which case
 .RB ` \-b '
 is ignored).  It can either be the name of a built-in curve (say
-.B "key add \-a ec\-param \-C list 42"
+.B "key show ec"
 for a list of curve names) or a full specification.  The curve is
 checked for correctness and security according to the SEC1
 specification: failed checks cause a warning to be issued to standard
@@ -868,7 +878,7 @@ decrypt locked keys.  Make sure nobody is looking over your shoulder
 when you do this!
 .SS "fingerprint"
 Reports a fingerprint (secure hash) on components of requested keys.
-The following option is supported:
+The following options are supported:
 .TP
 .BI "\-f, \-\-filter " filter
 Specifies a filter.  Only keys and key components which match the filter
@@ -877,7 +887,7 @@ components.
 .TP
 .BI "\-a, \-\-algorithm " hash
 Names the hashing algorithm.  Run
-.B hashsum -a list
+.B key show hash
 for a list of hashing algorithms.  The default is
 .BR rmd160 .
 .PP
@@ -886,6 +896,24 @@ command line arguments.  If no key tags are given, all keys which match
 the filter are fingerprinted.  See
 .BR keyring (5)
 for a description of how key fingerprints are computed.
+.SS "verify"
+Check a key's fingerprint against a reference copy.  The following
+options are supported:
+.TP
+.BI "\-f, \-\-filter " filter
+Specifies a filter.  Only key components which match the filter are
+hashed.  The default is to only fingerprint nonsecret components.  An
+error is reported if no part of the key matches.
+.TP
+.BI "\-a, \-\-algorithm " hash
+Names the hashing algorithm.  Run
+.B key show hash
+for a list of hashing algorithms.  The default is
+.BR rmd160 .
+.PP
+The reference fingerprint is given as hex, in upper or lower case.  The
+hash may contain hyphens, colons and whitespace.  Other characters are
+not permitted.
 .SS "tidy"
 Simply reads the keyring from file and writes it back again.  This has
 the effect of removing any deleted keys from the file.

diff --git a/keyutil.c b/keyutil.c
index 5e1fa66..1ead08d 100644 (file)
--- a/keyutil.c
+++ b/keyutil.c
@@ -31,6 +31,7 @@
 
 #include "config.h"
 
+#include <ctype.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -1695,6 +1696,101 @@ static int cmd_finger(int argc, char *argv[])
   return (rc);
 }
 
+/* --- @cmd_verify@ --- */
+
+static unsigned xdigit(char c)
+{
+  if ('A' <= c && c <= 'Z') return (c + 10 - 'A');
+  if ('a' <= c && c <= 'z') return (c + 10 - 'a');
+  if ('0' <= c && c <= '9') return (c - '0');
+  return (~0u);
+}
+
+static void unhexify(octet *q, char *p, size_t n)
+{
+  unsigned a = 0;
+  int i = 0;
+
+  for (;;) {
+    if (*p == '-' || *p == ':' || isspace((unsigned char)*p)) {
+      p++;
+      continue;
+    }
+    if (!n && !*p)
+      break;
+    if (!*p)
+      die(EXIT_FAILURE, "hex string too short");
+    if (!isxdigit((unsigned char)*p))
+      die(EXIT_FAILURE, "bad hex string");
+    if (!n)
+      die(EXIT_FAILURE, "hex string too long");
+    a = (a << 4) | xdigit(*p++);
+    i++;
+    if (i == 2) {
+      *q++ = U8(a);
+      a = 0;
+      i = 0;
+      n--;
+    }
+  }
+}
+
+static int cmd_verify(int argc, char *argv[])
+{
+  key_file f;
+  int rc = 0;
+  const gchash *ch = &rmd160;
+  ghash *h;
+  key *k;
+  octet *buf;
+  const octet *fpr;
+  key_filter kf = { KF_NONSECRET, KF_NONSECRET };
+
+  for (;;) {
+    static struct option opt[] = {
+      { "filter",      OPTF_ARGREQ,    0,      'f' },
+      { "algorithm",   OPTF_ARGREQ,    0,      'a' },
+      { 0,             0,              0,      0 }
+    };
+    int i = mdwopt(argc, argv, "+f:a:", opt, 0, 0, 0);
+    if (i < 0)
+      break;
+    switch (i) {
+      case 'f': {
+       char *p;
+       int err = key_readflags(optarg, &p, &kf.f, &kf.m);
+       if (err || *p)
+         die(EXIT_FAILURE, "bad filter string `%s'", optarg);
+      } break;
+      case 'a':
+       if ((ch = ghash_byname(optarg)) == 0)
+         die(EXIT_FAILURE, "unknown hash algorithm `%s'", optarg);
+       break;
+      default:
+       rc = 1;
+       break;
+    }
+  }
+
+  argv += optind; argc -= optind;
+  if (rc || argc != 2)
+    die(EXIT_FAILURE, "Usage: verify [-f FILTER] TAG FINGERPRINT");
+
+  doopen(&f, KOPEN_READ);
+
+  if ((k = key_bytag(&f, argv[0])) == 0)
+    die(EXIT_FAILURE, "key `%s' not found", argv[0]);
+  buf = xmalloc(ch->hashsz);
+  unhexify(buf, argv[1], ch->hashsz);
+  h = GH_INIT(ch);
+  if (!key_fingerprint(k, h, &kf))
+    die(EXIT_FAILURE, "key has no fingerprintable components (as filtered)");
+  fpr = GH_DONE(h, 0);
+  if (memcmp(fpr, buf, ch->hashsz) != 0)
+    die(EXIT_FAILURE, "key fingerprint mismatch");
+  return (0);
+}
+  
 /* --- @cmd_comment@ --- */
 
 static int cmd_comment(int argc, char *argv[])
@@ -1949,6 +2045,13 @@ Options:\n\
 -a, --algorithm=HASH   Use the named HASH algorithm.\n\
                          ($ show hash for list.)\n\
 " },
+  { "verify", cmd_verify, "verify [-f FILTER] TAG FINGERPRINT", "\
+Options:\n\
+\n\
+-f, --filter=FILT      Only hash key components matching FILT.\n\
+-a, --algorithm=HASH   Use the named HASH algorithm.\n\
+                         ($ show hash for list.)\n\
+" },
   { "extract", cmd_extract, "extract [-f FILTER] FILE [TAG...]", "\
 Options:\n\
 \n\