dropbear: bump to 2025.89 (CVE-2025-14282, CVE-2019-6111)

- Security: Avoid privilege escalation via unix stream forwarding in Dropbear
  server. Other programs on a system may authenticate unix sockets via
  SO_PEERCRED, which would be root user for Dropbear forwarded connections,
  allowing root privilege escalation.
  Reported by Turistu, and thanks for advice on the fix.
  This is tracked as CVE-2025-14282, and affects 2024.84 to 2025.88.

  It is fixed by dropping privileges of the dropbear process after
  authentication. Unix stream sockets are now disallowed when a
  forced command is used, either with authorized_key restrictions or
  "dropbear -c command".

  In previous affected releases running with "dropbear -j" (will also disable
  TCP fowarding) or building with localoptions.h/distrooptions.h
  "#define DROPBEAR_SVR_LOCALSTREAMFWD 0" is a mitigation.

- Security: Include scp fix for CVE-2019-6111. This allowed
  a malicious server to overwrite arbitrary local files.
  The missing fix was reported by Ashish Kunwar.

- Server dropping privileges post-auth is enabled by default. This requires
  setresgid() support, so some platforms such as netbsd or macos will have to
  disable DROPBEAR_SVR_DROP_PRIVS in localoptions.h. Unix stream forwarding is
  not available if DROPBEAR_SVR_DROP_PRIVS is disabled.

  Remote server TCP socket forwarding will now use OS privileged port
  restrictions rather than having a fixed "allow >=1024 for non-root" rule.

  A future release may implement privilege dropping for netbsd/macos.

- Fix a regression in 2025.87 when RSA and DSS are not built. This would lead
  to a crash at startup with bad_bufptr().
  Reported by Dani Schmitt and Sebastian Priebe.

- Don't limit channel window to 500MB. That is could cause stuck connections
  if peers advise a large window and don't send an increment within 500MB.
  Affects SSH.NET https://github.com/sshnet/SSH.NET/issues/1671
  Reported by Rob Hague.

- Ignore -g -s when passwords arent enabled. Patch from Norbert Lange.
  Ignore -m (disable MOTD), -j/-k (tcp forwarding) when not enabled.

- Report SIGBUS and SIGTRAP signals. Patch from Loïc Mangeonjean.

- Fix incorrect server auth delay. Was meant to be 250-350ms, it was actually
  150-350ms or possibly negative (zero). Reported by pickaxprograms.

- Fix building without public key options. Thanks to Konstantin Demin

- Fix building with proxycmd but without netcat. Thanks to Konstantin Demin

- Fix incorrect path documentation for distrooptions, thanks to Todd Zullinger

- Fix SO_REUSEADDR for TCP tests, reported by vt-alt.

Dropped:

 * 050-dropbear-multihop-fix.patch as its included in the release 5cc0127000db5f
 * 051-fix-pubkey-options.patch as its included in the release 1d4c4a542cd5df
 * 052-fix-missing-depends-for-sntrup761x25519-sha512.patch as its included
   in the release 1a2c1e649a1824
 * 053-Don-t-limit-channel-window-to-500MB.patch as its included in the release a8610f7b98ad

Manually rebased:

 * 110-change_user.patch

Fixes: CVE-2025-14282, CVE-2019-6111
Reviewed-by: Hauke Mehrtens <hauke@hauke-m.de>
Reviewed-by: Konstantin Demin <rockdrilla@gmail.com>
Tested-by: Konstantin Demin <rockdrilla@gmail.com> [mediatek/filogic (GL.iNet GL-MT6000)]
Link: https://github.com/openwrt/openwrt/pull/21186
Signed-off-by: Petr Štetiar <ynezz@true.cz>
This commit is contained in:
Petr Štetiar
2025-12-16 16:42:19 +00:00
parent 0bfc66e7b5
commit 70a4da1ceb
8 changed files with 13 additions and 214 deletions

View File

@@ -8,14 +8,14 @@
include $(TOPDIR)/rules.mk include $(TOPDIR)/rules.mk
PKG_NAME:=dropbear PKG_NAME:=dropbear
PKG_VERSION:=2025.88 PKG_VERSION:=2025.89
PKG_RELEASE:=4 PKG_RELEASE:=1
PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
PKG_SOURCE_URL:= \ PKG_SOURCE_URL:= \
https://matt.ucc.asn.au/dropbear/releases/ \ https://matt.ucc.asn.au/dropbear/releases/ \
https://dropbear.nl/mirror/releases/ https://dropbear.nl/mirror/releases/
PKG_HASH:=783f50ea27b17c16da89578fafdb6decfa44bb8f6590e5698a4e4d3672dc53d4 PKG_HASH:=0d1f7ca711cfc336dc8a85e672cab9cfd8223a02fe2da0a4a7aeb58c9e113634
PKG_LICENSE:=MIT PKG_LICENSE:=MIT
PKG_LICENSE_FILES:=LICENSE libtomcrypt/LICENSE libtommath/LICENSE PKG_LICENSE_FILES:=LICENSE libtomcrypt/LICENSE libtommath/LICENSE

View File

@@ -1,70 +0,0 @@
From 5cc0127000db5f7567b54d0495fb91a8e452fe09 Mon Sep 17 00:00:00 2001
From: Konstantin Demin <rockdrilla@gmail.com>
Date: Fri, 9 May 2025 22:39:35 +0300
Subject: Fix proxycmd without netcat
fixes e5a0ef27c2 "Execute multihop commands directly, no shell"
Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>
Forwarded: https://github.com/mkj/dropbear/pull/363
---
src/cli-main.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/src/cli-main.c
+++ b/src/cli-main.c
@@ -77,7 +77,11 @@ int main(int argc, char ** argv) {
}
#if DROPBEAR_CLI_PROXYCMD
- if (cli_opts.proxycmd || cli_opts.proxyexec) {
+ if (cli_opts.proxycmd
+#if DROPBEAR_CLI_MULTIHOP
+ || cli_opts.proxyexec
+#endif
+ ) {
cli_proxy_cmd(&sock_in, &sock_out, &proxy_cmd_pid);
if (signal(SIGINT, kill_proxy_sighandler) == SIG_ERR ||
signal(SIGTERM, kill_proxy_sighandler) == SIG_ERR ||
@@ -110,11 +114,13 @@ static void shell_proxy_cmd(const void *
dropbear_exit("Failed to run '%s'\n", cmd);
}
+#if DROPBEAR_CLI_MULTIHOP
static void exec_proxy_cmd(const void *unused) {
(void)unused;
run_command(cli_opts.proxyexec[0], cli_opts.proxyexec, ses.maxfd);
dropbear_exit("Failed to run '%s'\n", cli_opts.proxyexec[0]);
}
+#endif
static void cli_proxy_cmd(int *sock_in, int *sock_out, pid_t *pid_out) {
char * cmd_arg = NULL;
@@ -145,9 +151,11 @@ static void cli_proxy_cmd(int *sock_in,
cmd_arg = m_malloc(shell_cmdlen);
snprintf(cmd_arg, shell_cmdlen, "exec %s", cli_opts.proxycmd);
exec_fn = shell_proxy_cmd;
+#if DROPBEAR_CLI_MULTIHOP
} else {
/* No shell */
exec_fn = exec_proxy_cmd;
+#endif
}
ret = spawn_command(exec_fn, cmd_arg, sock_out, sock_in, NULL, pid_out);
@@ -159,6 +167,7 @@ static void cli_proxy_cmd(int *sock_in,
cleanup:
m_free(cli_opts.proxycmd);
m_free(cmd_arg);
+#if DROPBEAR_CLI_MULTIHOP
if (cli_opts.proxyexec) {
char **a = NULL;
for (a = cli_opts.proxyexec; *a; a++) {
@@ -166,6 +175,7 @@ cleanup:
}
m_free(cli_opts.proxyexec);
}
+#endif
}
static void kill_proxy_sighandler(int UNUSED(signo)) {

View File

@@ -1,47 +0,0 @@
From 91877a0337f432fd29bb1041be5599ea706e5de6 Mon Sep 17 00:00:00 2001
From: Konstantin Demin <rockdrilla@gmail.com>
Date: Thu, 31 Jul 2025 14:13:35 +0300
Subject: fix build without pubkey options
fixes:
- 98ef42a856 "Don't set pubkey_info directly in checkpubkey_line"
- 62ea53c1e5 "Implement no-touch-required and verify-requred for authorized_keys file"
Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>
Forwarded: https://github.com/mkj/dropbear/pull/374
---
src/svr-authpubkey.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/src/svr-authpubkey.c
+++ b/src/svr-authpubkey.c
@@ -186,12 +186,14 @@ void svr_auth_pubkey(int valid_user) {
#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
key->sk_flags_mask = SSH_SK_USER_PRESENCE_REQD;
+#if DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT
if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->no_touch_required_flag) {
key->sk_flags_mask &= ~SSH_SK_USER_PRESENCE_REQD;
}
if (ses.authstate.pubkey_options && ses.authstate.pubkey_options->verify_required_flag) {
key->sk_flags_mask |= SSH_SK_USER_VERIFICATION_REQD;
}
+#endif /* DROPBEAR_SVR_PUBKEY_OPTIONS */
#endif
/* create the data which has been signed - this a string containing
@@ -513,7 +515,13 @@ static int checkpubkey(const char* keyal
line_num++;
ret = checkpubkey_line(line, line_num, filename, keyalgo, keyalgolen,
- keyblob, keybloblen, &ses.authstate.pubkey_info);
+ keyblob, keybloblen,
+#if DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT
+ &ses.authstate.pubkey_info
+#else
+ NULL
+#endif
+ );
if (ret == DROPBEAR_SUCCESS) {
break;
}

View File

@@ -1,24 +0,0 @@
From 4bc1e18948d0918bcb1338a5f1e7856478abf985 Mon Sep 17 00:00:00 2001
From: Konstantin Demin <rockdrilla@gmail.com>
Date: Fri, 8 Aug 2025 10:02:44 +0300
Subject: fix missing depends for sntrup761x25519-sha512
fixes 440b7b5c4f "Add sntrup761x25519-sha512 post-quantum key exchange"
Signed-off-by: Konstantin Demin <rockdrilla@gmail.com>
Forwarded: https://github.com/mkj/dropbear/pull/375
---
src/sysoptions.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/src/sysoptions.h
+++ b/src/sysoptions.h
@@ -207,7 +207,7 @@
/* LTC SHA384 depends on SHA512 */
#define DROPBEAR_SHA512 ((DROPBEAR_SHA2_512_HMAC) || (DROPBEAR_ECC_521) \
|| (DROPBEAR_SHA384) || (DROPBEAR_DH_GROUP16) \
- || (DROPBEAR_ED25519))
+ || (DROPBEAR_ED25519) || (DROPBEAR_SNTRUP761))
#define DROPBEAR_DH_GROUP14 ((DROPBEAR_DH_GROUP14_SHA256) || (DROPBEAR_DH_GROUP14_SHA1))

View File

@@ -1,65 +0,0 @@
From a8610f7b98ad4b33ab723602863d60d462fa5af2 Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Sun, 10 Aug 2025 19:46:01 +0800
Subject: Don't limit channel window to 500MB
Previously the channel window and increments were limited to 500MB.
That is incorrect and causes stuck connections if peers advertise
a large window, then don't send an increment within the first 500MB.
That's seen with SSH.NET https://github.com/sshnet/SSH.NET/issues/1671
---
src/common-channel.c | 17 ++++++++++-------
src/sysoptions.h | 3 ---
2 files changed, 10 insertions(+), 10 deletions(-)
--- a/src/common-channel.c
+++ b/src/common-channel.c
@@ -858,17 +858,21 @@ void common_recv_msg_channel_data(struct Channel *channel, int fd,
void recv_msg_channel_window_adjust() {
struct Channel * channel;
- unsigned int incr;
+ unsigned int incr, newwin;
channel = getchannel();
incr = buf_getint(ses.payload);
- TRACE(("received window increment %d", incr))
- incr = MIN(incr, TRANS_MAX_WIN_INCR);
+ TRACE(("received window increment %u", incr))
- channel->transwindow += incr;
- channel->transwindow = MIN(channel->transwindow, TRANS_MAX_WINDOW);
-
+ newwin = channel->transwindow + incr;
+ if (newwin < channel->transwindow) {
+ /* Integer overflow, clamp it at maximum.
+ * Behaviour may be unexpected, senders MUST NOT overflow per rfc4254. */
+ TRACE(("overflow window, prev %u", channel->transwindow));
+ newwin = 0xffffffff;
+ }
+ channel->transwindow = newwin;
}
/* Increment the incoming data window for a channel, and let the remote
@@ -906,7 +910,6 @@ void recv_msg_channel_open() {
remotechan = buf_getint(ses.payload);
transwindow = buf_getint(ses.payload);
- transwindow = MIN(transwindow, TRANS_MAX_WINDOW);
transmaxpacket = buf_getint(ses.payload);
transmaxpacket = MIN(transmaxpacket, TRANS_MAX_PAYLOAD_LEN);
--- a/src/sysoptions.h
+++ b/src/sysoptions.h
@@ -243,9 +243,6 @@
#define RECV_MAX_PACKET_LEN (MAX(35000, ((RECV_MAX_PAYLOAD_LEN)+100)))
/* for channel code */
-#define TRANS_MAX_WINDOW 500000000 /* 500MB is sufficient, stopping overflow */
-#define TRANS_MAX_WIN_INCR 500000000 /* overflow prevention */
-
#define RECV_WINDOWEXTEND (opts.recv_window / 3) /* We send a "window extend" every
RECV_WINDOWEXTEND bytes */
#define MAX_RECV_WINDOW (10*1024*1024) /* 10 MB should be enough */

View File

@@ -1,6 +1,6 @@
--- a/src/svr-chansession.c --- a/src/svr-auth.c
+++ b/src/svr-chansession.c +++ b/src/svr-auth.c
@@ -984,12 +984,12 @@ static void execchild(const void *user_d @@ -510,9 +510,9 @@ void svr_switch_user(void) {
/* We can only change uid/gid as root ... */ /* We can only change uid/gid as root ... */
if (getuid() == 0) { if (getuid() == 0) {
@@ -11,6 +11,11 @@
+ ses.authstate.pw_gid) < 0))) { + ses.authstate.pw_gid) < 0))) {
dropbear_exit("Error changing user group"); dropbear_exit("Error changing user group");
} }
@@ -534,7 +534,7 @@ void svr_switch_user(void) {
}
#endif
- if (setuid(ses.authstate.pw_uid) < 0) { - if (setuid(ses.authstate.pw_uid) < 0) {
+ if ((ses.authstate.pw_uid != 0) && (setuid(ses.authstate.pw_uid) < 0)) { + if ((ses.authstate.pw_uid != 0) && (setuid(ses.authstate.pw_uid) < 0)) {
dropbear_exit("Error changing user"); dropbear_exit("Error changing user");

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@@ -1,6 +1,6 @@
--- a/configure.ac --- a/configure.ac
+++ b/configure.ac +++ b/configure.ac
@@ -86,54 +86,6 @@ AC_ARG_ENABLE(harden, @@ -80,54 +80,6 @@ AC_ARG_ENABLE(harden,
if test "$hardenbuild" -eq 1; then if test "$hardenbuild" -eq 1; then
AC_MSG_NOTICE(Checking for available hardened build flags:) AC_MSG_NOTICE(Checking for available hardened build flags:)

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@@ -1,6 +1,6 @@
--- a/configure.ac --- a/configure.ac
+++ b/configure.ac +++ b/configure.ac
@@ -44,11 +44,8 @@ fi @@ -38,11 +38,8 @@ fi
# LTM_CFLAGS is given to ./configure by the user, # LTM_CFLAGS is given to ./configure by the user,
# DROPBEAR_LTM_CFLAGS is substituted in the LTM Makefile.in # DROPBEAR_LTM_CFLAGS is substituted in the LTM Makefile.in
DROPBEAR_LTM_CFLAGS="$LTM_CFLAGS" DROPBEAR_LTM_CFLAGS="$LTM_CFLAGS"