[openssh-commits] [openssh] 03/03: upstream: Test all mutually supported algorithms,
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dtucker pushed a commit to branch master
in repository openssh.
commit f44f124a234785b9d2cd59a6da28737fb3c4ad9a
Author: dtucker at openbsd.org <dtucker at openbsd.org>
AuthorDate: Wed May 27 23:04:36 2026 +0000
upstream: Test all mutually supported algorithms,
using dropbear's new -Q option to query its algorithms where possible.
OpenBSD-Regress-ID: 7e1fa733dec3bfa9f8931e535a9397209b5953f3
---
regress/dropbear-server.sh | 202 +++++++++++++++++++++++++++++++++++++++------
1 file changed, 177 insertions(+), 25 deletions(-)
diff --git a/regress/dropbear-server.sh b/regress/dropbear-server.sh
index c72c86bfd..49379a53e 100644
--- a/regress/dropbear-server.sh
+++ b/regress/dropbear-server.sh
@@ -1,8 +1,14 @@
-# $OpenBSD: dropbear-server.sh,v 1.2 2025/06/29 05:35:00 dtucker Exp $
+# $OpenBSD: dropbear-server.sh,v 1.3 2026/05/27 23:04:36 dtucker Exp $
# Placed in the Public Domain.
tid="dropbear server"
+authkeydir=/var/run/dropbear-regress
+
+if [ -z "$SUDO" -a ! -w /var/run ]; then
+ skip "need SUDO to create dir in /var/run, test won't work without it"
+fi
+
if test "x$REGRESS_INTEROP_DROPBEAR" != "xyes" ; then
skip "dropbear interop tests not enabled"
fi
@@ -21,37 +27,158 @@ else
trace "dropbear version $ver (${major}.${minor}) ok"
fi
-if [ -z "$SUDO" -a ! -w /var/run ]; then
- skip "need SUDO to create dir in /var/run, test won't work without"
+# Dropbear versions 2026.91 and earlier only support 4 hostkeys in total,
+# however this was increased shortly after that release. Test for this.
+$SUDO $DROPBEARCONVERT openssh dropbear "$OBJ/host.ed25519" "$OBJ/db.25519" >/dev/null 2>&1
+$SUDO chown $USER $OBJ/$dbkey
+k="-r $OBJ/db.ed25519"
+if $DROPBEAR $k $k $k $k $k -V >/dev/null 2>&1; then
+ limit_4_hostkeys=no
+else
+ trace "dropbear supports only 4 host keys"
+ limit_4_hostkeys=yes
fi
-authkeydir=/var/run/dropbear-regress
-ciphers=`$DBCLIENT -c help hst 2>&1 | awk '/ ciphers: /{print $4}' | tr ',' ' '`
-macs=`$DBCLIENT -m help hst 2>&1 | awk '/ MACs: /{print $4}' | tr ',' ' '`
-if [ -z "$macs" ] || [ -z "$ciphers" ]; then
- skip "dbclient query ciphers '$ciphers' or macs '$macs' failed"
+#
+# Determine the set of algos supported by the Dropbear we're testing against.
+#
+if $DROPBEAR -Q help >/dev/null 2>&1; then
+ # We can directly query the server for supported algos.
+ dbciphers=`$DROPBEAR -Q cipher`
+ dbmacs=`$DROPBEAR -Q mac`
+ dbkexs=`$DROPBEAR -Q kex`
+ dbhkalgs=`$DROPBEAR -Q sig`
+ dbpktypes=`$DROPBEAR -Q sig`
+else
+ # We infer ciphers and macs from dbclient and hard code the rest.
+ # Since this test only supports back to Dropbear 2025.07 (due to the
+ # need for '-D') we have a pretty good idea what to hard code.
+ dbciphers=`$DBCLIENT -c help hst 2>&1 | awk '/ ciphers: /{print $4}' | tr ',' ' '`
+ dbmacs=`$DBCLIENT -m help hst 2>&1 | awk '/ MACs: /{print $4}' | tr ',' ' '`
+ dbkexs="curve25519-sha256 curve25519-sha256 at libssh.org"
+ dbkexs="$dbkexs diffie-hellman-group14-sha256"
+ dbkexs="$dbkexs ecdh-sha2-nistp256 ecdh-sha2-nistp384 ecdh-sha2-nistp521"
+ dbkexs="$dbkexs sntrup761x25519-sha512 mlkem768x25519-sha256"
+ dbhkalgs="ssh-ed25519 ecdsa-sha2-nistp256 ecdsa-sha2-nistp521 rsa-sha2-256"
+ dbpktypes="ecdsa-sha2-nistp256 ecdsa-sha2-nistp384 ecdsa-sha2-nistp521"
+ dbpktypes="$dbpktypes ssh-ed25519 rsa-sha2-256"
fi
+if [ -z "$dbmacs" ] || [ -z "$dbciphers" ] || [ -z "$dbkexs" ] || \
+ [ -z "$dbhkalgs" ] || [ -z "$dbpktypes" ]; then
+ fail "query ciphers '$dbciphers' macs '$dbmacs' kexs '$dbkexs' " \
+ "dbhkalgs '$dbhkalgs' or bpktypes '$bpktypes' failed"
+fi
+
+#
+# Filter out ciphers, macs and kexes not supported by the OpenSSH we're testing
+# and put the ones we want into ciphers, macs and kexes.
+#
+ciphers=""
+for c in $dbciphers; do
+ if $SSH -Q Ciphers | grep -E "^$c\$" >/dev/null; then
+ ciphers="$ciphers $c"
+ else
+ trace "ssh does not support cipher '$c'"
+ fi
+done
+
+macs=""
+for m in $dbmacs; do
+ if $SSH -Q MACs | grep -E "^$m\$" >/dev/null; then
+ macs="$macs $m"
+ else
+ trace "ssh does not support mac '$m'"
+ fi
+done
+
+kexs=""
+for k in $dbkexs; do
+ if $SSH -Q KexAlgorithms | grep -E "^$k\$" >/dev/null; then
+ kexs="$kexs $k"
+ else
+ trace "ssh does not support kex '$k'"
+ fi
+done
+
+#
+# Now filter by supported HostKeyAlgorithms. The key types are not a 1:1
+# correlation with the algos, so we first check that the algo is supported,
+# and if so put it in hkalgs add the appropriate key type to keytypes for
+# later deduplication and processing.
+#
+hkalgs=""
+keytypes=""
+for alg in $dbhkalgs; do
+ if ! $SSH -Q HostKeyAlgorithms | grep -E "^$alg\$" >/dev/null; then
+ trace "ssh does not support $alg"
+ alg=""
+ fi
+
+ kt="$alg"
+ case "$alg" in
+ sk-*)
+ trace "omitting sk alg $alg"
+ alg=""
+ ;;
+ ecdsa-sha2-nistp384)
+ if [ "$limit_4_hostkeys" = "yes" ]; then
+ trace "dropbear host key limit=4, omitting $alg"
+ alg=""
+ fi
+ ;;
+ rsa-sha2*)
+ kt=ssh-rsa
+ ;;
+ esac
+
+ if [ "$alg" != "" ]; then
+ hkalgs="$hkalgs $alg"
+ keytypes="$keytypes $kt"
+ fi
+done
+
+#
+# Deduplicate key types (because the various RSA hostkey algos use the same
+# type and Dropbear has a limit on the number of hostkeys it'll load) and
+# construct hkeyopts to be passed to dropbear command line.
+#
+hkeyopts=""
+for kt in `for i in $keytypes; do echo $i; done | sort -u`; do
+ key="host.$kt"
+ dbkey="db.$kt"
+ trace "convert hostkey '$key' to '$dbkey'"
+ if $SUDO $DROPBEARCONVERT openssh dropbear "$OBJ/$key" \
+ "$OBJ/$dbkey" >/dev/null 2>&1; then
+ if [ ! -f "$OBJ/$dbkey" ]; then
+ fail "convert $key to $dbkey"
+ fi
+ $SUDO chown $USER $OBJ/$dbkey
+ fi
+ trace "hkeyopts add -r $OBJ/db.$kt"
+ hkeyopts="$hkeyopts -r $OBJ/db.$kt"
+done
+
+pktypes=""
+for pk in $dbpktypes; do
+ if $SSH -Q PubkeyAcceptedAlgorithms | grep -E "^$pk\$" >/dev/null; then
+ case "$pk" in
+ sk-*) ;;
+ *) pktypes="$pktypes $pk" ;;
+ esac
+ else
+ trace "ssh does not support pubkey type '$pk'"
+ fi
+done
+
# Set up authorized_keys for dropbear.
umask 077
$SUDO mkdir -p $authkeydir
$SUDO chown -R $USER $authkeydir
cp $OBJ/authorized_keys_$USER $authkeydir/authorized_keys
-for i in `$SUDO $SSHD -f $OBJ/sshd_config -T | grep -v sk- | \
- awk '$1=="hostkey" {print $2}'`; do
- file=`basename "$i"`
- file=`echo "$file" | sed s/^host\./db\./g`
- if $SUDO $DROPBEARCONVERT openssh dropbear "$i" "$OBJ/$file" \
- >/dev/null 2>&1; then
- $SUDO chown $USER $OBJ/$file
- hkeys="-r $OBJ/$file"
- fi
-done
-
rm -f $OBJ/dropbear.pid
-$DROPBEAR -D $authkeydir -p $PORT -P $OBJ/dropbear.pid $hkeys -E \
- 2>$OBJ/sshd.log
+$DROPBEAR -E -D $authkeydir -p $PORT -P $OBJ/dropbear.pid $hkeyopts 2>>$OBJ/sshd.log
if [ $? -ne 0 ]; then
fatal "starting dropbear server failed"
fi
@@ -62,15 +189,40 @@ done
pid=`cat $OBJ/dropbear.pid`
trap "kill $pid; $SUDO rm -rf $authkeydir" 0
+trace ciphers $ciphers
+trace macs $macs
+trace kexs $kexs
+trace hkalgs $hkalgs
+trace pktypes $pktypes
+
for c in $ciphers; do
- for m in $macs; do
- trace "$tid: cipher $c mac $m hk $hk"
+ case "$c" in
+ chacha20-poly1305 at openssh.com|aes*-gcm at openssh.com)
+ tmpmacs="<implicit>" ;;
+ *)
+ tmpmacs="$macs" ;;
+ esac
+
+ for m in $tmpmacs; do
+ for k in $kexs; do
+ for hk in $hkalgs; do
+ for pk in $pktypes; do
+ verbose "$tid: cipher $c mac $m kex $k hkalg $hk pk $pk"
rm -f ${COPY}
- ${SSH} -F $OBJ/ssh_config -oCiphers=$c -oMacs=$m \
- somehost cat ${DATA} > ${COPY}
+ if [ "$m" = "<implicit>" ]; then
+ macopts=""
+ else
+ macopts="-oMacs=$m"
+ fi
+ ${SSH} -F $OBJ/ssh_config -oCiphers=$c $macopts -oKexAlgorithms=$k \
+ -oHostKeyAlgorithms=$hk -oPubkeyAcceptedAlgorithms=$pk \
+ somehost cat ${DATA} > ${COPY}
if [ $? -ne 0 ]; then
fail "connect dropbear server failed"
fi
cmp ${DATA} ${COPY} || fail "corrupted copy"
+ done
+ done
+ done
done
done
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