From 8ebd82645a8503ec1b8464586e5c19c18c009f06 Mon Sep 17 00:00:00 2001
From: Stephen Hemminger <shemminger@vyatta.com>
Date: Wed, 11 Jul 2012 09:29:22 -0700
Subject: Don't leak file descriptors to action

Bug 8204
Make sure we don't handle unnecessary file descriptors to child
processes. This is done by marking file descriptors as close on
exec, and closing pipe before exec.
---
 src/cli_new.c                         | 85 ++++++++++++++++++++++++-----------
 src/cstore/unionfs/cstore-unionfs.cpp |  7 ++-
 2 files changed, 66 insertions(+), 26 deletions(-)

(limited to 'src')

diff --git a/src/cli_new.c b/src/cli_new.c
index 716c06f..a7cd122 100644
--- a/src/cli_new.c
+++ b/src/cli_new.c
@@ -5,9 +5,19 @@
 #include <ctype.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 #include <fcntl.h>
+
+/* Workaround for features present in current kernel but
+   missing from old includes (glibc) in Debian Squeeze */
+#ifndef O_CLOEXEC
+#define O_CLOEXEC	02000000
+#endif
+#ifndef F_DUPFD_CLOEXEC
+#define F_DUPFD_CLOEXEC	0x406
+#endif
+
 #include <sys/wait.h>
-#include <unistd.h>
 #include <dirent.h>
 #include <limits.h>
 #include <stdarg.h>
@@ -2043,9 +2053,9 @@ static int set_reference_environment(const char* var_reference,
 
 /*** output ***/
 
+#define OUT_FD_MIN	16
 int out_fd = -1;
 FILE *out_stream = NULL;
-
 int err_fd = -1;
 FILE *err_stream = NULL;
 int new_out_fd = -1;
@@ -2054,35 +2064,55 @@ int new_err_fd = -1;
 int
 initialize_output(const char *op)
 {
-  if ((out_fd = dup(STDOUT_FILENO)) == -1) {
-    return -1;
-  }
-  if ((out_stream = fdopen(out_fd, "a")) == NULL) {
-    return -1;
-  }
-  if ((err_fd = dup(STDOUT_FILENO)) == -1) {
-    return -1;
-  }
-  if ((err_stream = fdopen(err_fd, "a")) == NULL) {
-    return -1;
+  out_fd = fcntl(STDOUT_FILENO, F_DUPFD_CLOEXEC, OUT_FD_MIN);
+  if (out_fd < 0)
+    goto err1;
+
+  out_stream = fdopen(out_fd, "w");
+  if (out_stream == NULL) {
+    close(out_fd);
+    goto err1;
   }
 
-  new_out_fd = open(LOGFILE_STDOUT, O_WRONLY | O_CREAT, 0660);
-  new_err_fd = open(LOGFILE_STDERR, O_WRONLY | O_CREAT, 0660);
-  if (new_out_fd == -1 || new_err_fd == -1) {
-    return -1;
-  }
-  if ((lseek(new_out_fd, 0, SEEK_END) == ((off_t) -1))
-      || (lseek(new_err_fd, 0, SEEK_END) == ((off_t) -1))) {
-    return -1;
+  err_fd = fcntl(STDERR_FILENO, F_DUPFD_CLOEXEC, OUT_FD_MIN);
+  if (err_fd < 0)
+    goto err2;
+
+  err_stream = fdopen(err_fd, "w");
+  if (err_stream == NULL) {
+    close(err_fd);
+    goto err2;
   }
+
+  new_out_fd = open(LOGFILE_STDOUT,
+		    O_WRONLY | O_CREAT | O_APPEND | O_CLOEXEC, 0660);
+  if (new_out_fd < 0)
+    goto err3;
+
+  new_err_fd = open(LOGFILE_STDERR,
+		    O_WRONLY | O_CREAT | O_APPEND | O_CLOEXEC, 0660);
+  if (new_err_fd < 0)
+    goto err4;
+
   if ((dup2(new_out_fd, STDOUT_FILENO) == -1)
-      || (dup2(new_err_fd, STDERR_FILENO) == -1)) {
-    return -1;
-  }
+      || (dup2(new_err_fd, STDERR_FILENO) == -1))
+    goto err5;
 
   cli_operation_name = op;
   return 0;
+
+err5:
+  close(new_err_fd); new_err_fd = -1;
+err4:
+  close(new_out_fd); new_out_fd = -1;
+err3:
+  fclose(err_stream);
+  err_stream = NULL; err_fd = -1;
+err2:
+  fclose(out_stream);
+  out_stream = NULL; out_fd = -1;
+err1:
+  return -1;
 }
 
 int
@@ -2139,11 +2169,14 @@ system_out(char *cmd, const char *prepend_msg, boolean eloc)
     int waited = 0;
     int prepend = 1;
 
+    close(pfd[1]);
+
     if (cpid == -1) {
+      close(pfd[0]);
+      fprintf(stderr, "fork failed\n");
       return -1;
     }
 
-    close(pfd[1]);
     while (1) {
       int sret;
       fd_set readfds;
@@ -2278,6 +2311,7 @@ system_out(char *cmd, const char *prepend_msg, boolean eloc)
         /* XXX XXX XXX END emulating original "error" location handling */
         if (out_stream != NULL) {
           if (fwrite(out, count, 1, out_stream) != 1) {
+	    close(pfd[0]);
             return -1;
           }
           fflush(out_stream);
@@ -2311,6 +2345,7 @@ system_out(char *cmd, const char *prepend_msg, boolean eloc)
         || (ret = dup2(pfd[1], STDERR_FILENO)) < 0) {
       exit(1);
     }
+    close(pfd[1]);
     char *eargs[] = { "sh", "-c", cmd, NULL };
     execv("/bin/sh", eargs);
     return -1; /* should not get here */
diff --git a/src/cstore/unionfs/cstore-unionfs.cpp b/src/cstore/unionfs/cstore-unionfs.cpp
index f8e54d7..7cfe23d 100644
--- a/src/cstore/unionfs/cstore-unionfs.cpp
+++ b/src/cstore/unionfs/cstore-unionfs.cpp
@@ -20,7 +20,9 @@
 #include <fstream>
 #include <sstream>
 
+#include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <sys/mount.h>
 
 #include <cli_cstore.h>
@@ -701,7 +703,10 @@ UnionfsCstore::commitConfig(commit::PrioNode& node)
 bool
 UnionfsCstore::getCommitLock()
 {
-  int fd = creat(C_COMMIT_LOCK_FILE.c_str(), 0777);
+  int fd;
+
+  fd = open(C_COMMIT_LOCK_FILE.c_str(),
+	    O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666);
   if (fd < 0) {
     // should not happen since all commit processes should have write access
     output_internal("getCommitLock() failed to open lock file\n");
-- 
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