Use bsd_closefrom.c from openssh-portable to fix #189

cbits/posix/bsd_closefrom.c

@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2004-2005 Todd C. Miller <[email protected]>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef HAVE_CLOSEFROM
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <unistd.h>
+#include <stdio.h>
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+#include <limits.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef HAVE_DIRENT_H
+# include <dirent.h>
+# define NAMLEN(dirent) strlen((dirent)->d_name)
+#else
+# define dirent direct
+# define NAMLEN(dirent) (dirent)->d_namlen
+# ifdef HAVE_SYS_NDIR_H
+#  include <sys/ndir.h>
+# endif
+# ifdef HAVE_SYS_DIR_H
+#  include <sys/dir.h>
+# endif
+# ifdef HAVE_NDIR_H
+#  include <ndir.h>
+# endif
+#endif
+#if defined(HAVE_LIBPROC_H)
+# include <libproc.h>
+#endif
+
+#ifndef OPEN_MAX
+# define OPEN_MAX	256
+#endif
+
+#if 0
+__unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
+#endif /* lint */
+
+#ifndef HAVE_FCNTL_CLOSEM
+/*
+ * Close all file descriptors greater than or equal to lowfd.
+ */
+static void
+closefrom_fallback(int lowfd)
+{
+	long fd, maxfd;
+
+	/*
+	 * Fall back on sysconf() or getdtablesize().  We avoid checking
+	 * resource limits since it is possible to open a file descriptor
+	 * and then drop the rlimit such that it is below the open fd.
+	 */
+#ifdef HAVE_SYSCONF
+	maxfd = sysconf(_SC_OPEN_MAX);
+#else
+	maxfd = getdtablesize();
+#endif /* HAVE_SYSCONF */
+	if (maxfd < 0)
+		maxfd = OPEN_MAX;
+
+	for (fd = lowfd; fd < maxfd; fd++)
+		(void) close((int) fd);
+}
+#endif /* HAVE_FCNTL_CLOSEM */
+
+#ifdef HAVE_FCNTL_CLOSEM
+void
+closefrom(int lowfd)
+{
+    (void) fcntl(lowfd, F_CLOSEM, 0);
+}
+#elif defined(HAVE_LIBPROC_H) && defined(HAVE_PROC_PIDINFO)
+void
+closefrom(int lowfd)
+{
+	int i, r, sz;
+	pid_t pid = getpid();
+	struct proc_fdinfo *fdinfo_buf = NULL;
+
+	sz = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, NULL, 0);
+	if (sz == 0)
+		return; /* no fds, really? */
+	else if (sz == -1)
+		goto fallback;
+	if ((fdinfo_buf = malloc(sz)) == NULL)
+		goto fallback;
+	r = proc_pidinfo(pid, PROC_PIDLISTFDS, 0, fdinfo_buf, sz);
+	if (r < 0 || r > sz)
+		goto fallback;
+	for (i = 0; i < r / (int)PROC_PIDLISTFD_SIZE; i++) {
+		if (fdinfo_buf[i].proc_fd >= lowfd)
+			close(fdinfo_buf[i].proc_fd);
+	}
+	free(fdinfo_buf);
+	return;
+ fallback:
+	free(fdinfo_buf);
+	closefrom_fallback(lowfd);
+	return;
+}
+#elif defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
+void
+closefrom(int lowfd)
+{
+    long fd;
+    char fdpath[PATH_MAX], *endp;
+    struct dirent *dent;
+    DIR *dirp;
+    int len;
+
+    /* Check for a /proc/$$/fd directory. */
+    len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
+    if (len > 0 && (size_t)len < sizeof(fdpath) && (dirp = opendir(fdpath))) {
+	while ((dent = readdir(dirp)) != NULL) {
+	    fd = strtol(dent->d_name, &endp, 10);
+	    if (dent->d_name != endp && *endp == '\0' &&
+		fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
+		(void) close((int) fd);
+	}
+	(void) closedir(dirp);
+	return;
+    }
+    /* /proc/$$/fd strategy failed, fall back to brute force closure */
+    closefrom_fallback(lowfd);
+}
+#else
+void
+closefrom(int lowfd)
+{
+	closefrom_fallback(lowfd);
+}
+#endif /* !HAVE_FCNTL_CLOSEM */
+#endif /* HAVE_CLOSEFROM */

cbits/posix/bsd_closefrom.h

@@ -0,0 +1,6 @@
+#ifndef BSD_CLOSEFROM_H_
+#define BSD_CLOSEFROM_H_
+
+void closefrom(int lowfd);
+
+#endif // BSD_CLOSEFROM_H_

cbits/posix/common.h

@@ -22,7 +22,7 @@ struct std_handle {
     };
 };
 
-int get_max_fd(void);
+void closefrom_excluding(int from, int excluding);
 
 // defined in find_executable.c
 #if !defined(HAVE_EXECVPE)

cbits/posix/fork_exec.c

@@ -222,13 +222,7 @@ do_spawn_fork (char *const args[],
         setup_std_handle_fork(STDERR_FILENO, stdErrHdl, forkCommunicationFds[1]);
 
         if ((flags & RUN_PROCESS_IN_CLOSE_FDS) != 0) {
-            int max_fd = get_max_fd();
-            // XXX Not the pipe
-            for (int i = 3; i < max_fd; i++) {
-                if (i != forkCommunicationFds[1]) {
-                    close(i);
-                }
-            }
+            closefrom_excluding(3, forkCommunicationFds[1]);
         }
 
         /* Reset the SIGINT/SIGQUIT signal handlers in the child, if requested

cbits/posix/runProcess.c

@@ -9,8 +9,11 @@
 
 #if defined(HAVE_FORK)
 
+#include "bsd_closefrom.h"
+
 #include <unistd.h>
 #include <errno.h>
+#include <sys/syscall.h>
 #include <sys/wait.h>
 
 #ifdef HAVE_FCNTL_H
@@ -21,21 +24,25 @@
 #include <signal.h>
 #endif
 
-int
-get_max_fd()
-{
-    static int cache = 0;
-    if (cache == 0) {
-#if HAVE_SYSCONF
-        cache = sysconf(_SC_OPEN_MAX);
-        if (cache == -1) {
-            cache = 256;
+#define CLOSE_RANGE_SYSCALL_NUMBER 436
+
+void
+closefrom_excluding(int lowfd, int excludingFd) {
+    // Try using the close_range syscall, provided in Linux kernel >= 5.9.
+    // We do this directly because not all C libs provide a wrapper (like musl)
+    long ret = syscall(CLOSE_RANGE_SYSCALL_NUMBER, lowfd, excludingFd - 1, 0);
+
+    if (ret != -1) {
+        // If that worked, closefrom the remaining range
+        closefrom(excludingFd + 1);
+    } else {
+        // Otherwise, fall back to a loop + closefrom
+        for (int i = lowfd; i < excludingFd; i++) {
+            close(i);
         }
-#else
-        cache = 256;
-#endif
+
+        closefrom(excludingFd + 1);
     }
-    return cache;
 }
 
 // If a process was terminated by a signal, the exit status we return

configure.ac

@@ -16,6 +16,18 @@ AC_CHECK_HEADERS([signal.h sys/wait.h fcntl.h])
 AC_CHECK_FUNCS([setitimer sysconf])
 AC_CHECK_FUNCS([execvpe])
 
+# check for headers and functions used by bsd_closefrom.c
+AC_CHECK_HEADERS([dirent.h fcntl.h libproc.h linux/close_range.h ndir.h sys/dir.h sys/ndir.h])
+AC_CHECK_FUNCS([closefrom close_range dirfd proc_pidinfo sysconf])
+AC_MSG_CHECKING([for /proc/pid/fd directory])
+if test -d "/proc/$$/fd" ; then
+	AC_DEFINE([HAVE_PROC_PID], [1], [Define if you have /proc/$pid/fd])
+	AC_MSG_RESULT([yes])
+else
+	AC_MSG_RESULT([no])
+fi
+
+
 # posix_spawn checks
 AC_CHECK_HEADERS([spawn.h])
 AC_CHECK_FUNCS([posix_spawnp posix_spawn_file_actions_addchdir],[],[],[

process.cabal

@@ -57,6 +57,11 @@ library
     if os(windows)
         c-sources:
             cbits/win32/runProcess.c
+        includes:
+            runProcess.h
+        install-includes:
+            runProcess.h
+            processFlags.h
         other-modules: System.Process.Windows
         build-depends: Win32 >=2.4 && < 2.14
         -- ole32 and rpcrt4 are needed to create GUIDs for unique named pipes
@@ -66,18 +71,21 @@ library
     else
         c-sources:
             cbits/posix/runProcess.c
+            cbits/posix/bsd_closefrom.c
             cbits/posix/fork_exec.c
             cbits/posix/posix_spawn.c
             cbits/posix/find_executable.c
+        includes:
+            runProcess.h
+            cbits/posix/bsd_closefrom.h
+        install-includes:
+            runProcess.h
+            processFlags.h
+            cbits/posix/bsd_closefrom.h
         other-modules: System.Process.Posix
         build-depends: unix >= 2.5 && < 2.9
 
     include-dirs: include
-    includes:
-        runProcess.h
-    install-includes:
-        runProcess.h
-        processFlags.h
 
     ghc-options: -Wall