diff --git a/openssh-7.1p2-fallback-x11-untrusted.patch b/openssh-7.1p2-fallback-x11-untrusted.patch new file mode 100644 index 0000000..1fecbfd --- /dev/null +++ b/openssh-7.1p2-fallback-x11-untrusted.patch @@ -0,0 +1,352 @@ +From f98a09cacff7baad8748c9aa217afd155a4d493f Mon Sep 17 00:00:00 2001 +From: "mmcc@openbsd.org" +Date: Tue, 20 Oct 2015 03:36:35 +0000 +Subject: [PATCH] upstream commit + +Replace a function-local allocation with stack memory. + +ok djm@ + +Upstream-ID: c09fbbab637053a2ab9f33ca142b4e20a4c5a17e +--- + clientloop.c | 9 ++------- + 1 file changed, 2 insertions(+), 7 deletions(-) + +diff --git a/clientloop.c b/clientloop.c +index 87ceb3d..1e05cba 100644 +--- a/clientloop.c ++++ b/clientloop.c +@@ -311,11 +311,10 @@ client_x11_get_proto(const char *display, const char *xauth_path, + static char proto[512], data[512]; + FILE *f; + int got_data = 0, generated = 0, do_unlink = 0, i; +- char *xauthdir, *xauthfile; ++ char xauthdir[PATH_MAX] = "", xauthfile[PATH_MAX] = ""; + struct stat st; + u_int now, x11_timeout_real; + +- xauthdir = xauthfile = NULL; + *_proto = proto; + *_data = data; + proto[0] = data[0] = '\0'; +@@ -343,8 +342,6 @@ client_x11_get_proto(const char *display, const char *xauth_path, + display = xdisplay; + } + if (trusted == 0) { +- xauthdir = xmalloc(PATH_MAX); +- xauthfile = xmalloc(PATH_MAX); + mktemp_proto(xauthdir, PATH_MAX); + /* + * The authentication cookie should briefly outlive +@@ -407,8 +404,6 @@ client_x11_get_proto(const char *display, const char *xauth_path, + unlink(xauthfile); + rmdir(xauthdir); + } +- free(xauthdir); +- free(xauthfile); + + /* + * If we didn't get authentication data, just make up some +-- +2.5.0 + +From ed4ce82dbfa8a3a3c8ea6fa0db113c71e234416c Mon Sep 17 00:00:00 2001 +From: "djm@openbsd.org" +Date: Wed, 13 Jan 2016 23:04:47 +0000 +Subject: [PATCH] upstream commit + +eliminate fallback from untrusted X11 forwarding to trusted + forwarding when the X server disables the SECURITY extension; Reported by + Thomas Hoger; ok deraadt@ + +Upstream-ID: f76195bd2064615a63ef9674a0e4096b0713f938 +--- + clientloop.c | 114 ++++++++++++++++++++++++++++++++++++----------------------- + clientloop.h | 4 +-- + mux.c | 22 ++++++------ + ssh.c | 23 +++++------- + 4 files changed, 93 insertions(+), 70 deletions(-) + +diff --git a/clientloop.c b/clientloop.c +index f555451..c0386d5 100644 +--- a/clientloop.c ++++ b/clientloop.c +@@ -288,6 +288,9 @@ client_x11_display_valid(const char *display) + { + size_t i, dlen; + ++ if (display == NULL) ++ return 0; ++ + dlen = strlen(display); + for (i = 0; i < dlen; i++) { + if (!isalnum((u_char)display[i]) && +@@ -301,34 +304,33 @@ client_x11_display_valid(const char *display) + + #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" + #define X11_TIMEOUT_SLACK 60 +-void ++int + client_x11_get_proto(const char *display, const char *xauth_path, + u_int trusted, u_int timeout, char **_proto, char **_data) + { +- char cmd[1024]; +- char line[512]; +- char xdisplay[512]; ++ char cmd[1024], line[512], xdisplay[512]; ++ char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; + static char proto[512], data[512]; + FILE *f; +- int got_data = 0, generated = 0, do_unlink = 0, i; +- char xauthdir[PATH_MAX] = "", xauthfile[PATH_MAX] = ""; ++ int got_data = 0, generated = 0, do_unlink = 0, i, r; + struct stat st; + u_int now, x11_timeout_real; + + *_proto = proto; + *_data = data; +- proto[0] = data[0] = '\0'; ++ proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; + +- if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { +- debug("No xauth program."); +- } else if (!client_x11_display_valid(display)) { +- logit("DISPLAY '%s' invalid, falling back to fake xauth data", ++ if (!client_x11_display_valid(display)) { ++ logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", + display); +- } else { +- if (display == NULL) { +- debug("x11_get_proto: DISPLAY not set"); +- return; +- } ++ return -1; ++ } ++ if (xauth_path != NULL && stat(xauth_path, &st) == -1) { ++ debug("No xauth program."); ++ xauth_path = NULL; ++ } ++ ++ if (xauth_path != NULL) { + /* + * Handle FamilyLocal case where $DISPLAY does + * not match an authorization entry. For this we +@@ -337,43 +339,60 @@ client_x11_get_proto(const char *display, const char *xauth_path, + * is not perfect. + */ + if (strncmp(display, "localhost:", 10) == 0) { +- snprintf(xdisplay, sizeof(xdisplay), "unix:%s", +- display + 10); ++ if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", ++ display + 10)) < 0 || ++ (size_t)r >= sizeof(xdisplay)) { ++ error("%s: display name too long", __func__); ++ return -1; ++ } + display = xdisplay; + } + if (trusted == 0) { +- mktemp_proto(xauthdir, PATH_MAX); + /* ++ * Generate an untrusted X11 auth cookie. ++ * + * The authentication cookie should briefly outlive + * ssh's willingness to forward X11 connections to + * avoid nasty fail-open behaviour in the X server. + */ ++ mktemp_proto(xauthdir, sizeof(xauthdir)); ++ if (mkdtemp(xauthdir) == NULL) { ++ error("%s: mkdtemp: %s", ++ __func__, strerror(errno)); ++ return -1; ++ } ++ do_unlink = 1; ++ if ((r = snprintf(xauthfile, sizeof(xauthfile), ++ "%s/xauthfile", xauthdir)) < 0 || ++ (size_t)r >= sizeof(xauthfile)) { ++ error("%s: xauthfile path too long", __func__); ++ unlink(xauthfile); ++ rmdir(xauthdir); ++ return -1; ++ } ++ + if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK) + x11_timeout_real = UINT_MAX; + else + x11_timeout_real = timeout + X11_TIMEOUT_SLACK; +- if (mkdtemp(xauthdir) != NULL) { +- do_unlink = 1; +- snprintf(xauthfile, PATH_MAX, "%s/xauthfile", +- xauthdir); +- snprintf(cmd, sizeof(cmd), +- "%s -f %s generate %s " SSH_X11_PROTO +- " untrusted timeout %u 2>" _PATH_DEVNULL, +- xauth_path, xauthfile, display, +- x11_timeout_real); +- debug2("x11_get_proto: %s", cmd); +- if (x11_refuse_time == 0) { +- now = monotime() + 1; +- if (UINT_MAX - timeout < now) +- x11_refuse_time = UINT_MAX; +- else +- x11_refuse_time = now + timeout; +- channel_set_x11_refuse_time( +- x11_refuse_time); +- } +- if (system(cmd) == 0) +- generated = 1; ++ if ((r = snprintf(cmd, sizeof(cmd), ++ "%s -f %s generate %s " SSH_X11_PROTO ++ " untrusted timeout %u 2>" _PATH_DEVNULL, ++ xauth_path, xauthfile, display, ++ x11_timeout_real)) < 0 || ++ (size_t)r >= sizeof(cmd)) ++ fatal("%s: cmd too long", __func__); ++ debug2("%s: %s", __func__, cmd); ++ if (x11_refuse_time == 0) { ++ now = monotime() + 1; ++ if (UINT_MAX - timeout < now) ++ x11_refuse_time = UINT_MAX; ++ else ++ x11_refuse_time = now + timeout; ++ channel_set_x11_refuse_time(x11_refuse_time); + } ++ if (system(cmd) == 0) ++ generated = 1; + } + + /* +@@ -395,9 +414,7 @@ client_x11_get_proto(const char *display, const char *xauth_path, + got_data = 1; + if (f) + pclose(f); +- } else +- error("Warning: untrusted X11 forwarding setup failed: " +- "xauth key data not generated"); ++ } + } + + if (do_unlink) { +@@ -405,6 +422,13 @@ client_x11_get_proto(const char *display, const char *xauth_path, + rmdir(xauthdir); + } + ++ /* Don't fall back to fake X11 data for untrusted forwarding */ ++ if (!trusted && !got_data) { ++ error("Warning: untrusted X11 forwarding setup failed: " ++ "xauth key data not generated"); ++ return -1; ++ } ++ + /* + * If we didn't get authentication data, just make up some + * data. The forwarding code will check the validity of the +@@ -427,6 +451,8 @@ client_x11_get_proto(const char *display, const char *xauth_path, + rnd >>= 8; + } + } ++ ++ return 0; + } + + /* +diff --git a/clientloop.h b/clientloop.h +index 338d451..f4d4c69 100644 +--- a/clientloop.h ++++ b/clientloop.h +@@ -39,7 +39,7 @@ + + /* Client side main loop for the interactive session. */ + int client_loop(int, int, int); +-void client_x11_get_proto(const char *, const char *, u_int, u_int, ++int client_x11_get_proto(const char *, const char *, u_int, u_int, + char **, char **); + void client_global_request_reply_fwd(int, u_int32_t, void *); + void client_session2_setup(int, int, int, const char *, struct termios *, +diff --git a/mux.c b/mux.c +index f9c3af6..6bf53eb 100644 +--- a/mux.c ++++ b/mux.c +@@ -1354,16 +1354,18 @@ mux_session_confirm(int id, int success, void *arg) + char *proto, *data; + + /* Get reasonable local authentication information. */ +- client_x11_get_proto(display, options.xauth_location, ++ if (client_x11_get_proto(display, options.xauth_location, + options.forward_x11_trusted, options.forward_x11_timeout, +- &proto, &data); +- /* Request forwarding with authentication spoofing. */ +- debug("Requesting X11 forwarding with authentication " +- "spoofing."); +- x11_request_forwarding_with_spoofing(id, display, proto, +- data, 1); +- client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); +- /* XXX exit_on_forward_failure */ ++ &proto, &data) == 0) { ++ /* Request forwarding with authentication spoofing. */ ++ debug("Requesting X11 forwarding with authentication " ++ "spoofing."); ++ x11_request_forwarding_with_spoofing(id, display, proto, ++ data, 1); ++ /* XXX exit_on_forward_failure */ ++ client_expect_confirm(id, "X11 forwarding", ++ CONFIRM_WARN); ++ } + } + + if (cctx->want_agent_fwd && options.forward_agent) { +diff --git a/ssh.c b/ssh.c +index 81704ab..096c5b5 100644 +--- a/ssh.c ++++ b/ssh.c +@@ -1626,6 +1626,7 @@ ssh_session(void) + struct winsize ws; + char *cp; + const char *display; ++ char *proto = NULL, *data = NULL; + + /* Enable compression if requested. */ + if (options.compression) { +@@ -1696,13 +1697,9 @@ ssh_session(void) + display = getenv("DISPLAY"); + if (display == NULL && options.forward_x11) + debug("X11 forwarding requested but DISPLAY not set"); +- if (options.forward_x11 && display != NULL) { +- char *proto, *data; +- /* Get reasonable local authentication information. */ +- client_x11_get_proto(display, options.xauth_location, +- options.forward_x11_trusted, +- options.forward_x11_timeout, +- &proto, &data); ++ if (options.forward_x11 && client_x11_get_proto(display, ++ options.xauth_location, options.forward_x11_trusted, ++ options.forward_x11_timeout, &proto, &data) == 0) { + /* Request forwarding with authentication spoofing. */ + debug("Requesting X11 forwarding with authentication " + "spoofing."); +@@ -1792,6 +1789,7 @@ ssh_session2_setup(int id, int success, void *arg) + extern char **environ; + const char *display; + int interactive = tty_flag; ++ char *proto = NULL, *data = NULL; + + if (!success) + return; /* No need for error message, channels code sens one */ +@@ -1799,12 +1797,9 @@ ssh_session2_setup(int id, int success, void *arg) + display = getenv("DISPLAY"); + if (display == NULL && options.forward_x11) + debug("X11 forwarding requested but DISPLAY not set"); +- if (options.forward_x11 && display != NULL) { +- char *proto, *data; +- /* Get reasonable local authentication information. */ +- client_x11_get_proto(display, options.xauth_location, +- options.forward_x11_trusted, +- options.forward_x11_timeout, &proto, &data); ++ if (options.forward_x11 && client_x11_get_proto(display, ++ options.xauth_location, options.forward_x11_trusted, ++ options.forward_x11_timeout, &proto, &data) == 0) { + /* Request forwarding with authentication spoofing. */ + debug("Requesting X11 forwarding with authentication " + "spoofing."); +-- +2.5.0 diff --git a/openssh.spec b/openssh.spec index 4cf8aba..2c83ef0 100644 --- a/openssh.spec +++ b/openssh.spec @@ -234,6 +234,8 @@ Patch935: openssh-7.1p1-ssh-copy-id.patch # Preserve IUTF8 tty mode flag over ssh connections (#1270248) # https://bugzilla.mindrot.org/show_bug.cgi?id=2477 Patch936: openssh-7.1p1-iutf8.patch +# CVE-2016-1908: possible fallback from untrusted to trusted X11 forwarding +Patch937: openssh-7.1p2-fallback-x11-untrusted.patch License: BSD @@ -471,6 +473,7 @@ popd %patch934 -p1 -b .hostkey %patch935 -p1 -b .ssh-copy-id %patch936 -p1 -b .iutf8 +%patch937 -p1 -b .x11-fallback %patch200 -p1 -b .audit %patch700 -p1 -b .fips