From: markus <markus@openbsd.org>
Date: Mon, 8 Jan 2018 15:21:49 +0000 (+0000)
Subject: move subprocess() so scp/sftp do not need uidswap.o; ok djm@
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=879b4d6e86491b14cf1919bf424e9e7b2f821073;p=openbsd

move subprocess() so scp/sftp do not need uidswap.o; ok djm@
---

diff --git a/usr.bin/ssh/auth.c b/usr.bin/ssh/auth.c
index 5abae6d5d69..09066864653 100644
--- a/usr.bin/ssh/auth.c
+++ b/usr.bin/ssh/auth.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.c,v 1.124 2017/09/12 06:32:07 djm Exp $ */
+/* $OpenBSD: auth.c,v 1.125 2018/01/08 15:21:49 markus Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -26,6 +26,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
+#include <sys/wait.h>
 
 #include <errno.h>
 #include <fcntl.h>
@@ -706,3 +707,155 @@ auth_get_canonical_hostname(struct ssh *ssh, int use_dns)
 		return dnsname;
 	}
 }
+
+/*
+ * Runs command in a subprocess wuth a minimal environment.
+ * Returns pid on success, 0 on failure.
+ * The child stdout and stderr maybe captured, left attached or sent to
+ * /dev/null depending on the contents of flags.
+ * "tag" is prepended to log messages.
+ * NB. "command" is only used for logging; the actual command executed is
+ * av[0].
+ */
+pid_t
+subprocess(const char *tag, struct passwd *pw, const char *command,
+    int ac, char **av, FILE **child, u_int flags)
+{
+	FILE *f = NULL;
+	struct stat st;
+	int fd, devnull, p[2], i;
+	pid_t pid;
+	char *cp, errmsg[512];
+	u_int envsize;
+	char **child_env;
+
+	if (child != NULL)
+		*child = NULL;
+
+	debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__,
+	    tag, command, pw->pw_name, flags);
+
+	/* Check consistency */
+	if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
+	    (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
+		error("%s: inconsistent flags", __func__);
+		return 0;
+	}
+	if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
+		error("%s: inconsistent flags/output", __func__);
+		return 0;
+	}
+
+	/*
+	 * If executing an explicit binary, then verify the it exists
+	 * and appears safe-ish to execute
+	 */
+	if (*av[0] != '/') {
+		error("%s path is not absolute", tag);
+		return 0;
+	}
+	temporarily_use_uid(pw);
+	if (stat(av[0], &st) < 0) {
+		error("Could not stat %s \"%s\": %s", tag,
+		    av[0], strerror(errno));
+		restore_uid();
+		return 0;
+	}
+	if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
+		error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
+		restore_uid();
+		return 0;
+	}
+	/* Prepare to keep the child's stdout if requested */
+	if (pipe(p) != 0) {
+		error("%s: pipe: %s", tag, strerror(errno));
+		restore_uid();
+		return 0;
+	}
+	restore_uid();
+
+	switch ((pid = fork())) {
+	case -1: /* error */
+		error("%s: fork: %s", tag, strerror(errno));
+		close(p[0]);
+		close(p[1]);
+		return 0;
+	case 0: /* child */
+		/* Prepare a minimal environment for the child. */
+		envsize = 5;
+		child_env = xcalloc(sizeof(*child_env), envsize);
+		child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH);
+		child_set_env(&child_env, &envsize, "USER", pw->pw_name);
+		child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name);
+		child_set_env(&child_env, &envsize, "HOME", pw->pw_dir);
+		if ((cp = getenv("LANG")) != NULL)
+			child_set_env(&child_env, &envsize, "LANG", cp);
+
+		for (i = 0; i < NSIG; i++)
+			signal(i, SIG_DFL);
+
+		if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
+			error("%s: open %s: %s", tag, _PATH_DEVNULL,
+			    strerror(errno));
+			_exit(1);
+		}
+		if (dup2(devnull, STDIN_FILENO) == -1) {
+			error("%s: dup2: %s", tag, strerror(errno));
+			_exit(1);
+		}
+
+		/* Set up stdout as requested; leave stderr in place for now. */
+		fd = -1;
+		if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
+			fd = p[1];
+		else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
+			fd = devnull;
+		if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
+			error("%s: dup2: %s", tag, strerror(errno));
+			_exit(1);
+		}
+		closefrom(STDERR_FILENO + 1);
+
+		/* Don't use permanently_set_uid() here to avoid fatal() */
+		if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
+			error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
+			    strerror(errno));
+			_exit(1);
+		}
+		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
+			error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
+			    strerror(errno));
+			_exit(1);
+		}
+		/* stdin is pointed to /dev/null at this point */
+		if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
+		    dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
+			error("%s: dup2: %s", tag, strerror(errno));
+			_exit(1);
+		}
+
+		execve(av[0], av, child_env);
+		error("%s exec \"%s\": %s", tag, command, strerror(errno));
+		_exit(127);
+	default: /* parent */
+		break;
+	}
+
+	close(p[1]);
+	if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
+		close(p[0]);
+	else if ((f = fdopen(p[0], "r")) == NULL) {
+		error("%s: fdopen: %s", tag, strerror(errno));
+		close(p[0]);
+		/* Don't leave zombie child */
+		kill(pid, SIGTERM);
+		while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
+			;
+		return 0;
+	}
+	/* Success */
+	debug3("%s: %s pid %ld", __func__, tag, (long)pid);
+	if (child != NULL)
+		*child = f;
+	return pid;
+}
diff --git a/usr.bin/ssh/auth.h b/usr.bin/ssh/auth.h
index ba6036e3abc..a4cb1204fd8 100644
--- a/usr.bin/ssh/auth.h
+++ b/usr.bin/ssh/auth.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: auth.h,v 1.93 2017/08/18 05:36:45 djm Exp $ */
+/* $OpenBSD: auth.h,v 1.94 2018/01/08 15:21:49 markus Exp $ */
 
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
@@ -195,4 +195,10 @@ void	 auth_debug_reset(void);
 
 struct passwd *fakepw(void);
 
+#define	SSH_SUBPROCESS_STDOUT_DISCARD  (1)     /* Discard stdout */
+#define	SSH_SUBPROCESS_STDOUT_CAPTURE  (1<<1)  /* Redirect stdout */
+#define	SSH_SUBPROCESS_STDERR_DISCARD  (1<<2)  /* Discard stderr */
+pid_t	subprocess(const char *, struct passwd *,
+    const char *, int, char **, FILE **, u_int flags);
+
 #endif
diff --git a/usr.bin/ssh/misc.c b/usr.bin/ssh/misc.c
index c1ad2dc3a77..acf58d2c57a 100644
--- a/usr.bin/ssh/misc.c
+++ b/usr.bin/ssh/misc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.122 2017/12/08 02:14:33 djm Exp $ */
+/* $OpenBSD: misc.c,v 1.123 2018/01/08 15:21:49 markus Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -1664,158 +1664,6 @@ argv_assemble(int argc, char **argv)
 	return ret;
 }
 
-/*
- * Runs command in a subprocess wuth a minimal environment.
- * Returns pid on success, 0 on failure.
- * The child stdout and stderr maybe captured, left attached or sent to
- * /dev/null depending on the contents of flags.
- * "tag" is prepended to log messages.
- * NB. "command" is only used for logging; the actual command executed is
- * av[0].
- */
-pid_t
-subprocess(const char *tag, struct passwd *pw, const char *command,
-    int ac, char **av, FILE **child, u_int flags)
-{
-	FILE *f = NULL;
-	struct stat st;
-	int fd, devnull, p[2], i;
-	pid_t pid;
-	char *cp, errmsg[512];
-	u_int envsize;
-	char **child_env;
-
-	if (child != NULL)
-		*child = NULL;
-
-	debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__,
-	    tag, command, pw->pw_name, flags);
-
-	/* Check consistency */
-	if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
-	    (flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
-		error("%s: inconsistent flags", __func__);
-		return 0;
-	}
-	if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
-		error("%s: inconsistent flags/output", __func__);
-		return 0;
-	}
-
-	/*
-	 * If executing an explicit binary, then verify the it exists
-	 * and appears safe-ish to execute
-	 */
-	if (*av[0] != '/') {
-		error("%s path is not absolute", tag);
-		return 0;
-	}
-	temporarily_use_uid(pw);
-	if (stat(av[0], &st) < 0) {
-		error("Could not stat %s \"%s\": %s", tag,
-		    av[0], strerror(errno));
-		restore_uid();
-		return 0;
-	}
-	if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
-		error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
-		restore_uid();
-		return 0;
-	}
-	/* Prepare to keep the child's stdout if requested */
-	if (pipe(p) != 0) {
-		error("%s: pipe: %s", tag, strerror(errno));
-		restore_uid();
-		return 0;
-	}
-	restore_uid();
-
-	switch ((pid = fork())) {
-	case -1: /* error */
-		error("%s: fork: %s", tag, strerror(errno));
-		close(p[0]);
-		close(p[1]);
-		return 0;
-	case 0: /* child */
-		/* Prepare a minimal environment for the child. */
-		envsize = 5;
-		child_env = xcalloc(sizeof(*child_env), envsize);
-		child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH);
-		child_set_env(&child_env, &envsize, "USER", pw->pw_name);
-		child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name);
-		child_set_env(&child_env, &envsize, "HOME", pw->pw_dir);
-		if ((cp = getenv("LANG")) != NULL)
-			child_set_env(&child_env, &envsize, "LANG", cp);
-
-		for (i = 0; i < NSIG; i++)
-			signal(i, SIG_DFL);
-
-		if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
-			error("%s: open %s: %s", tag, _PATH_DEVNULL,
-			    strerror(errno));
-			_exit(1);
-		}
-		if (dup2(devnull, STDIN_FILENO) == -1) {
-			error("%s: dup2: %s", tag, strerror(errno));
-			_exit(1);
-		}
-
-		/* Set up stdout as requested; leave stderr in place for now. */
-		fd = -1;
-		if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
-			fd = p[1];
-		else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
-			fd = devnull;
-		if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
-			error("%s: dup2: %s", tag, strerror(errno));
-			_exit(1);
-		}
-		closefrom(STDERR_FILENO + 1);
-
-		/* Don't use permanently_set_uid() here to avoid fatal() */
-		if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
-			error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
-			    strerror(errno));
-			_exit(1);
-		}
-		if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) {
-			error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
-			    strerror(errno));
-			_exit(1);
-		}
-		/* stdin is pointed to /dev/null at this point */
-		if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
-		    dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
-			error("%s: dup2: %s", tag, strerror(errno));
-			_exit(1);
-		}
-
-		execve(av[0], av, child_env);
-		error("%s exec \"%s\": %s", tag, command, strerror(errno));
-		_exit(127);
-	default: /* parent */
-		break;
-	}
-
-	close(p[1]);
-	if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
-		close(p[0]);
-	else if ((f = fdopen(p[0], "r")) == NULL) {
-		error("%s: fdopen: %s", tag, strerror(errno));
-		close(p[0]);
-		/* Don't leave zombie child */
-		kill(pid, SIGTERM);
-		while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
-			;
-		return 0;
-	}
-	/* Success */
-	debug3("%s: %s pid %ld", __func__, tag, (long)pid);
-	if (child != NULL)
-		*child = f;
-	return pid;
-}
-
 /* Returns 0 if pid exited cleanly, non-zero otherwise */
 int
 exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet)
diff --git a/usr.bin/ssh/misc.h b/usr.bin/ssh/misc.h
index a81a124e624..4c8ee3d59a7 100644
--- a/usr.bin/ssh/misc.h
+++ b/usr.bin/ssh/misc.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.h,v 1.69 2017/12/05 23:59:47 dtucker Exp $ */
+/* $OpenBSD: misc.h,v 1.70 2018/01/08 15:21:49 markus Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -147,12 +147,6 @@ int	 argv_split(const char *, int *, char ***);
 char	*argv_assemble(int, char **argv);
 int	 exited_cleanly(pid_t, const char *, const char *, int);
 
-#define SSH_SUBPROCESS_STDOUT_DISCARD	(1)	/* Discard stdout */
-#define SSH_SUBPROCESS_STDOUT_CAPTURE	(1<<1)	/* Redirect stdout */
-#define SSH_SUBPROCESS_STDERR_DISCARD	(1<<2)	/* Discard stderr */
-pid_t	 subprocess(const char *, struct passwd *,
-    const char *, int, char **, FILE **, u_int flags);
-
 struct stat;
 int	 safe_path(const char *, struct stat *, const char *, uid_t,
 	     char *, size_t);
diff --git a/usr.bin/ssh/scp/Makefile b/usr.bin/ssh/scp/Makefile
index ff6baa43a33..0e5aaeda70c 100644
--- a/usr.bin/ssh/scp/Makefile
+++ b/usr.bin/ssh/scp/Makefile
@@ -1,10 +1,10 @@
-#	$OpenBSD: Makefile,v 1.18 2017/12/10 19:37:57 deraadt Exp $
+#	$OpenBSD: Makefile,v 1.19 2018/01/08 15:21:49 markus Exp $
 
 .PATH:		${.CURDIR}/..
 
 SRCS=	scp.c
 SRCS+=	atomicio.c cleanup.c fatal.c log.c misc.c progressmeter.c \
-	sshbuf-getput-basic.c sshbuf.c ssherr.c uidswap.c utf8.c xmalloc.c
+	sshbuf-getput-basic.c sshbuf.c ssherr.c utf8.c xmalloc.c
 
 PROG=	scp
 BINOWN=	root
diff --git a/usr.bin/ssh/sftp/Makefile b/usr.bin/ssh/sftp/Makefile
index 102c6d32a9b..4a1d597af83 100644
--- a/usr.bin/ssh/sftp/Makefile
+++ b/usr.bin/ssh/sftp/Makefile
@@ -1,10 +1,10 @@
-#	$OpenBSD: Makefile,v 1.14 2017/12/10 19:37:57 deraadt Exp $
+#	$OpenBSD: Makefile,v 1.15 2018/01/08 15:21:49 markus Exp $
 
 .PATH:		${.CURDIR}/..
 
 SRCS=	sftp.c sftp-client.c sftp-common.c sftp-glob.c
 SRCS+=	atomicio.c cleanup.c fatal.c log.c misc.c progressmeter.c \
-	sshbuf-getput-basic.c sshbuf.c ssherr.c uidswap.c utf8.c xmalloc.c
+	sshbuf-getput-basic.c sshbuf.c ssherr.c utf8.c xmalloc.c
 
 PROG=	sftp
 BINOWN=	root