handle cr+lf (instead of just cr) in sshsig signature files

diff --git a/usr.bin/ssh/sshsig.c b/usr.bin/ssh/sshsig.c
index 3f02c90..b358015 100644 (file)
--- a/usr.bin/ssh/sshsig.c
+++ b/usr.bin/ssh/sshsig.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshsig.c,v 1.32 2023/04/06 03:56:02 djm Exp $ */
+/* $OpenBSD: sshsig.c,v 1.33 2023/09/06 23:18:15 djm Exp $ */
 /*
  * Copyright (c) 2019 Google LLC
  *
@@ -36,7 +36,7 @@
 #define SIG_VERSION            0x01
 #define MAGIC_PREAMBLE         "SSHSIG"
 #define MAGIC_PREAMBLE_LEN     (sizeof(MAGIC_PREAMBLE) - 1)
-#define BEGIN_SIGNATURE                "-----BEGIN SSH SIGNATURE-----\n"
+#define BEGIN_SIGNATURE                "-----BEGIN SSH SIGNATURE-----"
 #define END_SIGNATURE          "-----END SSH SIGNATURE-----"
 #define RSA_SIGN_ALG           "rsa-sha2-512" /* XXX maybe make configurable */
 #define RSA_SIGN_ALLOWED       "rsa-sha2-512,rsa-sha2-256"
@@ -57,8 +57,7 @@ sshsig_armor(const struct sshbuf *blob, struct sshbuf **out)
                goto out;
        }
 
-       if ((r = sshbuf_put(buf, BEGIN_SIGNATURE,
-           sizeof(BEGIN_SIGNATURE)-1)) != 0) {
+       if ((r = sshbuf_putf(buf, "%s\n", BEGIN_SIGNATURE)) != 0) {
                error_fr(r, "sshbuf_putf");
                goto out;
        }
@@ -97,23 +96,35 @@ sshsig_dearmor(struct sshbuf *sig, struct sshbuf **out)
                return SSH_ERR_ALLOC_FAIL;
        }
 
+       /* Expect and consume preamble + lf/crlf */
        if ((r = sshbuf_cmp(sbuf, 0,
            BEGIN_SIGNATURE, sizeof(BEGIN_SIGNATURE)-1)) != 0) {
                error("Couldn't parse signature: missing header");
                goto done;
        }
-
        if ((r = sshbuf_consume(sbuf, sizeof(BEGIN_SIGNATURE)-1)) != 0) {
                error_fr(r, "consume");
                goto done;
        }
-
+       if ((r = sshbuf_cmp(sbuf, 0, "\r\n", 2)) == 0)
+               eoffset = 2;
+       else if ((r = sshbuf_cmp(sbuf, 0, "\n", 1)) == 0)
+               eoffset = 1;
+       else {
+               r = SSH_ERR_INVALID_FORMAT;
+               error_f("no header eol");
+               goto done;
+       }
+       if ((r = sshbuf_consume(sbuf, eoffset)) != 0) {
+               error_fr(r, "consume eol");
+               goto done;
+       }
+       /* Find and consume lf + suffix (any prior cr would be ignored) */
        if ((r = sshbuf_find(sbuf, 0, "\n" END_SIGNATURE,
-           sizeof("\n" END_SIGNATURE)-1, &eoffset)) != 0) {
+           sizeof(END_SIGNATURE), &eoffset)) != 0) {
                error("Couldn't parse signature: missing footer");
                goto done;
        }
-
        if ((r = sshbuf_consume_end(sbuf, sshbuf_len(sbuf)-eoffset)) != 0) {
                error_fr(r, "consume");
                goto done;