From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 8 Jul 2014 06:24:07 +0000 (-0700)
Subject: * process.c: Add sanity checks for file descriptors.
X-Git-Tag: emacs-25.0.90~2636^2~67
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=12dc5429352223f7ba8314d2e16177036a762733;p=emacs.git

* process.c: Add sanity checks for file descriptors.

(wait_reading_process_output, Fprocess_filter_multibyte_p):
Check that infd is nonnegative before using it as an fd.
(read_and_dispose_of_process_output, Fprocess_send_eof):
Likewise, for outfd.
(wait_reading_process_output): Omit unnecessary check of infd.

Fixes: debbugs:17844
---

diff --git a/src/ChangeLog b/src/ChangeLog
index 2e6ad094382..e854c2e1c39 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,12 @@
+2014-07-08  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* process.c: Add sanity checks for file descriptors (Bug#17844).
+	(wait_reading_process_output, Fprocess_filter_multibyte_p):
+	Check that infd is nonnegative before using it as an fd.
+	(read_and_dispose_of_process_output, Fprocess_send_eof):
+	Likewise, for outfd.
+	(wait_reading_process_output): Omit unnecessary check of infd.
+
 2014-07-07  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Minor fixups related to usage of the 'long' type.
diff --git a/src/process.c b/src/process.c
index 3242222a94a..d1b14533c99 100644
--- a/src/process.c
+++ b/src/process.c
@@ -4462,6 +4462,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
       if (wait_proc && wait_proc->raw_status_new)
 	update_status (wait_proc);
       if (wait_proc
+	  && wait_proc->infd >= 0
 	  && ! EQ (wait_proc->status, Qrun)
 	  && ! EQ (wait_proc->status, Qconnect))
 	{
@@ -4471,7 +4472,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 	  XSETPROCESS (proc, wait_proc);
 
 	  /* Read data from the process, until we exhaust it.  */
-	  while (wait_proc->infd >= 0)
+	  while (true)
 	    {
 	      int nread = read_process_output (proc, wait_proc->infd);
 	      if (nread < 0)
@@ -4642,6 +4643,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 			  > 0))
 		    {
 		      nfds = 1;
+		      eassert (0 <= wait_proc->infd);
 		      /* Set to Available.  */
 		      FD_SET (wait_proc->infd, &Available);
 		    }
@@ -4909,7 +4911,8 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 		     status_notify to do it later, it will read input
 		     from the process before calling the sentinel.  */
 		  exec_sentinel (proc, build_string ("open\n"));
-		  if (!EQ (p->filter, Qt) && !EQ (p->command, Qt))
+		  if (0 <= p->infd && !EQ (p->filter, Qt)
+		      && !EQ (p->command, Qt))
 		    {
 		      FD_SET (p->infd, &input_wait_mask);
 		      FD_SET (p->infd, &non_keyboard_wait_mask);
@@ -5131,7 +5134,7 @@ read_and_dispose_of_process_output (struct Lisp_Process *p, char *chars,
 	 proc_encode_coding_system[p->outfd] surely points to a
 	 valid memory because p->outfd will be changed once EOF is
 	 sent to the process.  */
-      if (NILP (p->encode_coding_system)
+      if (NILP (p->encode_coding_system) && p->outfd
 	  && proc_encode_coding_system[p->outfd])
 	{
 	  pset_encode_coding_system
@@ -6071,8 +6074,8 @@ process has been transmitted to the serial port.  */)
 	 for communication with the subprocess, call shutdown to cause EOF.
 	 (In some old system, shutdown to socketpair doesn't work.
 	 Then we just can't win.)  */
-      if (EQ (p->type, Qnetwork)
-	  || p->infd == old_outfd)
+      if (0 <= old_outfd
+	  && (EQ (p->type, Qnetwork) || p->infd == old_outfd))
 	shutdown (old_outfd, 1);
 #endif
       close_process_fd (&p->open_fd[WRITE_TO_SUBPROCESS]);
@@ -6546,6 +6549,8 @@ DEFUN ("process-filter-multibyte-p", Fprocess_filter_multibyte_p,
 
   CHECK_PROCESS (process);
   p = XPROCESS (process);
+  if (p->infd < 0)
+    return Qnil;
   coding = proc_decode_coding_system[p->infd];
   return (CODING_FOR_UNIBYTE (coding) ? Qnil : Qt);
 }