Attachment 3365 Details for Bug 3129 – use sshpkt_fatal() for kex_exchange_identification() errors

[patch] use sshpkt_fatal() for kex_exchange_identification() errors

bz3129.diff (text/plain), 3.60 KB, created by Damien Miller on 2020-03-13 14:07:54 AEDT

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Creator: Damien Miller

Created: 2020-03-13 14:07:54 AEDT

Size: 3.60 KB

patch

obsolete

>diff --git a/kex.c b/kex.c
>index 899036e6e..bfdb33e29 100644
>--- a/kex.c
>+++ b/kex.c
>@@ -1167,7 +1167,7 @@ int
> kex_exchange_identification(struct ssh *ssh, int timeout_ms,
>     const char *version_addendum)
> {
>-	int remote_major, remote_minor, mismatch;
>+	int remote_major, remote_minor, mismatch, oerrno = 0;
> 	size_t len, i, n;
> 	int r, expect_nl;
> 	u_char c;
>@@ -1186,6 +1186,7 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
> 	   PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,
> 	    version_addendum == NULL ? "" : " ",
> 	    version_addendum == NULL ? "" : version_addendum)) != 0) {
>+		oerrno = errno;
> 		error("%s: sshbuf_putf: %s", __func__, ssh_err(r));
> 		goto out;
> 	}
>@@ -1193,11 +1194,13 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
> 	if (atomicio(vwrite, ssh_packet_get_connection_out(ssh),
> 	    sshbuf_mutable_ptr(our_version),
> 	    sshbuf_len(our_version)) != sshbuf_len(our_version)) {
>-		error("%s: write: %.100s", __func__, strerror(errno));
>+		oerrno = errno;
>+		debug("%s: write: %.100s", __func__, strerror(errno));
> 		r = SSH_ERR_SYSTEM_ERROR;
> 		goto out;
> 	}
> 	if ((r = sshbuf_consume_end(our_version, 2)) != 0) { /* trim \r\n */
>+		oerrno = errno;
> 		error("%s: sshbuf_consume_end: %s", __func__, ssh_err(r));
> 		goto out;
> 	}
>@@ -1233,6 +1236,7 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
> 					r = SSH_ERR_CONN_TIMEOUT;
> 					goto out;
> 				} else if (r == -1) {
>+					oerrno = errno;
> 					error("%s: %s",
> 					    __func__, strerror(errno));
> 					r = SSH_ERR_SYSTEM_ERROR;
>@@ -1248,6 +1252,7 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
> 				r = SSH_ERR_CONN_CLOSED;
> 				goto out;
> 			} else if (len != 1) {
>+				oerrno = errno;
> 				error("%s: read: %.100s",
> 				    __func__, strerror(errno));
> 				r = SSH_ERR_SYSTEM_ERROR;
>@@ -1265,6 +1270,7 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
> 				goto invalid;
> 			}
> 			if ((r = sshbuf_put_u8(peer_version, c)) != 0) {
>+				oerrno = errno;
> 				error("%s: sshbuf_put: %s",
> 				    __func__, ssh_err(r));
> 				goto out;
>@@ -1365,6 +1371,8 @@ kex_exchange_identification(struct ssh *ssh, int timeout_ms,
> 	free(our_version_string);
> 	free(peer_version_string);
> 	free(remote_version);
>+	if (r == SSH_ERR_SYSTEM_ERROR)
>+		errno = oerrno;
> 	return r;
> }
> 
>diff --git a/sshconnect.c b/sshconnect.c
>index 4711af782..7263562cb 100644
>--- a/sshconnect.c
>+++ b/sshconnect.c
>@@ -1276,6 +1276,7 @@ ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
> {
> 	char *host;
> 	char *server_user, *local_user;
>+	int r;
> 
> 	local_user = xstrdup(pw->pw_name);
> 	server_user = options.user ? options.user : local_user;
>@@ -1285,8 +1286,8 @@ ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
> 	lowercase(host);
> 
> 	/* Exchange protocol version identification strings with the server. */
>-	if (kex_exchange_identification(ssh, timeout_ms, NULL) != 0)
>-		cleanup_exit(255); /* error already logged */
>+	if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
>+		sshpkt_fatal(ssh, r, "banner exchange");
> 
> 	/* Put the connection into non-blocking mode. */
> 	ssh_packet_set_nonblocking(ssh);
>diff --git a/sshd.c b/sshd.c
>index 60b2aaf73..5b8a04637 100644
>--- a/sshd.c
>+++ b/sshd.c
>@@ -2161,8 +2161,9 @@ main(int ac, char **av)
> 	if (!debug_flag)
> 		alarm(options.login_grace_time);
> 
>-	if (kex_exchange_identification(ssh, -1, options.version_addendum) != 0)
>-		cleanup_exit(255); /* error already logged */
>+	if ((r = kex_exchange_identification(ssh, -1,
>+	    options.version_addendum)) != 0)
>+		sshpkt_fatal(ssh, r, "banner exchange");
> 
> 	ssh_packet_set_nonblocking(ssh);
>

Flags:

dtucker: ok+

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Attachments on bug 3129: 3359 | 3365