OpenSSH: Update to 10.4p1

Full release notes are available at
https://www.openssh.com/txt/release-10.4

Selected highlights from the release notes:

Potentially-incompatible changes
--------------------------------

 * sshd(8): configuration dump mode ("sshd -G") now writes directives
   in mixed case (e.g. "PubkeyAuthentication") whereas previously it
   emitted only lower-case names.

 * ssh(1), sshd(8): make the transport protocol stricter by
   disconnecting if the peer sends non-KEX messages during a post-
   authentication key re-exchange. Previously a malicious peer could
   continue sending non-key exchange messages without penalty. These
   would be buffered, causing memory to be wasted up until the
   connection terminated or the server/client hit a memory limit.
   Implementations that do not restrict messages sent during key
   exchange as per RFC4253 section 7.1 may be disconnected.
   Reported by Marko Jevtic.

Changes since OpenSSH 10.3
==========================

This release contains a number of security fixes as well as general
bugfixes and a couple of new features.

Security
========

 * sftp(1): when downloading files on the command-line using
   "sftp host:/path .", a malicious server could cause the file to
   be downloaded to an unexpected location. This issue was identified
   by the Swival Security Scanner.

 * scp(1): when copying files between two remote destinations, do
   not allow a malicious server to write files to the parent
   directory of the intended target directory.  This issue was
   identified by the Swival Security Scanner.

 * sshd(8): DisableForwarding=yes didn't override PermitTunnel=yes
   as it was documented to do. Note that PermitTunnel is not enabled
   by default. Reported independently by Huzaifa Sidhpurwala of
   Redhat and Marko Jevtic.

 * sshd(8): avoid a potential pre-authentication denial of service
   when GSSAPIAuthentication was enabled (this feature is off by
   default). This was not mitigated by MaxAuthTries, but would be
   penalised by PerSourcePenalties. This was reported by Manfred
   Kaiser of the milCERT AT (Austrian Ministry of Defence).

 * sshd(8): fix a number of cases where the minimum authentication
   delay was not being enforced. Reported by the Orange Cyberdefense
   Vulnerability Team.

 * ssh(1): fix a possible client-side use-after-free if the server
   changes its host key during a key reexchange. This was reported by
   Zhenpeng (Leo) Lin of Depthfirst.

New features
------------

 * All: add experimental support for a composite post-quantum
   signature scheme that combines ML-DSA 44 and Ed25519 as specified
   in draft-miller-sshm-mldsa44-ed25519-composite-sigs.

   This scheme is not enabled by default. To use it, you'll need
   to add it to HostKeyAlgorithms, PubkeyAcceptedAlgorithms, etc.
   Keys may be generated using "ssh-keygen -t mldsa44-ed25519".

Bugfixes
--------

 * sshd(8): avoid sending observably different messages for valid vs
   invalid users in GSSAPIAuthentication (disabled by default).

 * ssh(1), sshd(8): fix several bugs that incorrectly
   classified bulk traffic as interactive. bz3972, bz3958

 * ssh-keygen(1), ssh-add(1): skip unsupported key types when
   downloading resident keys from a FIDO token. Previously, downloads
   would abort when one was encountered. GHPR657

Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D58083

1 files changed, 37 insertions, 33 deletions

diff --git a/crypto/openssh/session.c b/crypto/openssh/session.c
index 0517d538762a..1dd4b647062b 100644
--- a/crypto/openssh/session.c
+++ b/crypto/openssh/session.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: session.c,v 1.348 2026/03/05 05:40:36 djm Exp $ */
+/* $OpenBSD: session.c,v 1.350 2026/06/05 08:53:07 djm Exp $ */
 /*
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
@@ -1625,21 +1625,22 @@ do_child(struct ssh *ssh, Session *s, const char *command)
 		exit(1);
 	} else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
 		extern int optind, optreset;
-		int i;
-		char *p, *args;
+		int sftp_argc;
+		char **sftp_argv;
 
 		setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
-		args = xstrdup(command ? command : "sftp-server");
-		for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
-			if (i < ARGV_MAX - 1)
-				argv[i++] = p;
-		argv[i] = NULL;
+		if (argv_split(command == NULL ? "sftp-server" : command,
+		    &sftp_argc, &sftp_argv, 1) != 0) {
+			error("internal error: can't split internal-sftp "
+			    "arguments");
+			exit(1);
+		}
 		optind = optreset = 1;
-		__progname = argv[0];
+		__progname = sftp_argv[0];
 #ifdef WITH_SELINUX
 		ssh_selinux_change_context("sftpd_t");
 #endif
-		exit(sftp_server_main(i, argv, s->pw));
+		exit(sftp_server_main(sftp_argc, sftp_argv, s->pw));
 	}
 
 	fflush(NULL);
@@ -1925,7 +1926,7 @@ static int
 session_subsystem_req(struct ssh *ssh, Session *s)
 {
 	struct stat st;
-	int r, success = 0;
+	int r, success = 0, found = 0;
 	char *prog, *cmd, *type;
 	u_int i;
 
@@ -1936,31 +1937,34 @@ session_subsystem_req(struct ssh *ssh, Session *s)
 	    s->pw->pw_name);
 
 	for (i = 0; i < options.num_subsystems; i++) {
-		if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
-			prog = options.subsystem_command[i];
-			cmd = options.subsystem_args[i];
-			if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
-				s->is_subsystem = SUBSYSTEM_INT_SFTP;
-				debug("subsystem: %s", prog);
-			} else {
-				if (stat(prog, &st) == -1)
-					debug("subsystem: cannot stat %s: %s",
-					    prog, strerror(errno));
-				s->is_subsystem = SUBSYSTEM_EXT;
-				debug("subsystem: exec() %s", cmd);
-			}
-			xasprintf(&type, "session:subsystem:%s",
-			    options.subsystem_name[i]);
-			channel_set_xtype(ssh, s->chanid, type);
-			free(type);
-			success = do_exec(ssh, s, cmd) == 0;
-			break;
+		if (strcmp(s->subsys, options.subsystem_name[i]) != 0)
+			continue;
+		found = 1;
+		prog = options.subsystem_command[i];
+		cmd = options.subsystem_args[i];
+		if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
+			s->is_subsystem = SUBSYSTEM_INT_SFTP;
+			debug("subsystem: %s", prog);
+		} else {
+			if (stat(prog, &st) == -1)
+				debug("subsystem: cannot stat %s: %s",
+				    prog, strerror(errno));
+			s->is_subsystem = SUBSYSTEM_EXT;
+			debug("subsystem: exec() %s", cmd);
 		}
+		xasprintf(&type, "session:subsystem:%s",
+		    options.subsystem_name[i]);
+		channel_set_xtype(ssh, s->chanid, type);
+		free(type);
+		success = do_exec(ssh, s, cmd) == 0;
+		break;
 	}
 
-	if (!success)
-		logit("subsystem request for %.100s by user %s failed, "
-		    "subsystem not found", s->subsys, s->pw->pw_name);
+	if (!success) {
+		logit("subsystem request for %.100s by user %s failed, %s",
+		    s->subsys, s->pw->pw_name,
+		    found ? "execution failed" : "subsystem not found");
+	}
 
 	return success;
 }