Attachment 3521 Details for Bug 3279 – dump failed key and signature

[patch] dump failed key and signature

bz3279_debug.diff (text/plain), 1.65 KB, created by Damien Miller on 2021-05-20 11:43:37 AEST

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Creator: Damien Miller

Created: 2021-05-20 11:43:37 AEST

Size: 1.65 KB

patch

obsolete

>commit 222829df23144b7271dd0b99aeef9d255b759ba2
>Author: Damien Miller <djm@mindrot.org>
>Date:   Thu May 20 11:38:28 2021 +1000
>
>    debug sigverify fail
>
>diff --git a/auth2-pubkey.c b/auth2-pubkey.c
>index 721c1d9bd..0b2a3c88a 100644
>--- a/auth2-pubkey.c
>+++ b/auth2-pubkey.c
>@@ -95,7 +95,7 @@ userauth_pubkey(struct ssh *ssh)
> 	char *pkalg = NULL, *userstyle = NULL, *key_s = NULL, *ca_s = NULL;
> 	u_char *pkblob = NULL, *sig = NULL, have_sig;
> 	size_t blen, slen;
>-	int r, pktype;
>+	int v, r, pktype;
> 	int req_presence = 0, req_verify = 0, authenticated = 0;
> 	struct sshauthopt *authopts = NULL;
> 	struct sshkey_sig_details *sig_details = NULL;
>@@ -202,13 +202,23 @@ userauth_pubkey(struct ssh *ssh)
> #endif
> 		/* test for correct signature */
> 		authenticated = 0;
>+		v = 0;
> 		if (PRIVSEP(user_key_allowed(ssh, pw, key, 1, &authopts)) &&
>-		    PRIVSEP(sshkey_verify(key, sig, slen,
>+		    (v = PRIVSEP(sshkey_verify(key, sig, slen,
> 		    sshbuf_ptr(b), sshbuf_len(b),
> 		    (ssh->compat & SSH_BUG_SIGTYPE) == 0 ? pkalg : NULL,
>-		    ssh->compat, &sig_details)) == 0) {
>+		    ssh->compat, &sig_details))) == 0) {
> 			authenticated = 1;
> 		}
>+		if (v < 0) {
>+			struct sshbuf *badkey = sshbuf_new();
>+			debug_fr(v, "sshkey_verify failed");
>+			sshkey_format_text(key, badkey);
>+			sshbuf_put_u8(badkey, 0);
>+			debug_f("failed key: %s", (const char *)sshbuf_ptr(badkey));
>+			debug_f("failed alg: %s", ((ssh->compat & SSH_BUG_SIGTYPE) == 0 && pkalg != NULL) ? pkalg : "[DEFAULT]");
>+			debug_f("failed sig: %s", tohex(sig, slen));
>+		}
> 		if (authenticated == 1 && sig_details != NULL) {
> 			auth2_record_info(authctxt, "signature count = %u",
> 			    sig_details->sk_counter);

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