143 lines
4.3 KiB
Diff
143 lines
4.3 KiB
Diff
From b3a0ca3deed00334f9feece43f76776b6a168e47 Mon Sep 17 00:00:00 2001
|
|
From: Andreas Gruenbacher <agruen@gnu.org>
|
|
Date: Fri, 6 Apr 2018 12:14:49 +0200
|
|
Subject: [PATCH] Fix arbitrary command execution in ed-style patches
|
|
(CVE-2018-1000156)
|
|
|
|
* src/pch.c (do_ed_script): Write ed script to a temporary file instead
|
|
of piping it to ed: this will cause ed to abort on invalid commands
|
|
instead of rejecting them and carrying on.
|
|
* tests/ed-style: New test case.
|
|
* tests/Makefile.am (TESTS): Add test case.
|
|
---
|
|
src/pch.c | 89 +++++++++++++++++++++++++++++++++++++++++--------------
|
|
1 file changed, 66 insertions(+), 23 deletions(-)
|
|
|
|
--- a/src/pch.c
|
|
+++ b/src/pch.c
|
|
@@ -33,6 +33,7 @@
|
|
# include <io.h>
|
|
#endif
|
|
#include <safe.h>
|
|
+#include <sys/wait.h>
|
|
|
|
#define INITHUNKMAX 125 /* initial dynamic allocation size */
|
|
|
|
@@ -2389,22 +2390,28 @@ do_ed_script (char const *inname, char c
|
|
static char const editor_program[] = EDITOR_PROGRAM;
|
|
|
|
file_offset beginning_of_this_line;
|
|
- FILE *pipefp = 0;
|
|
size_t chars_read;
|
|
+ FILE *tmpfp = 0;
|
|
+ char const *tmpname;
|
|
+ int tmpfd;
|
|
+ pid_t pid;
|
|
+
|
|
+ if (! dry_run && ! skip_rest_of_patch)
|
|
+ {
|
|
+ /* Write ed script to a temporary file. This causes ed to abort on
|
|
+ invalid commands such as when line numbers or ranges exceed the
|
|
+ number of available lines. When ed reads from a pipe, it rejects
|
|
+ invalid commands and treats the next line as a new command, which
|
|
+ can lead to arbitrary command execution. */
|
|
+
|
|
+ tmpfd = make_tempfile (&tmpname, 'e', NULL, O_RDWR | O_BINARY, 0);
|
|
+ if (tmpfd == -1)
|
|
+ pfatal ("Can't create temporary file %s", quotearg (tmpname));
|
|
+ tmpfp = fdopen (tmpfd, "w+b");
|
|
+ if (! tmpfp)
|
|
+ pfatal ("Can't open stream for file %s", quotearg (tmpname));
|
|
+ }
|
|
|
|
- if (! dry_run && ! skip_rest_of_patch) {
|
|
- int exclusive = *outname_needs_removal ? 0 : O_EXCL;
|
|
- assert (! inerrno);
|
|
- *outname_needs_removal = true;
|
|
- copy_file (inname, outname, 0, exclusive, instat.st_mode, true);
|
|
- sprintf (buf, "%s %s%s", editor_program,
|
|
- verbosity == VERBOSE ? "" : "- ",
|
|
- outname);
|
|
- fflush (stdout);
|
|
- pipefp = popen(buf, binary_transput ? "wb" : "w");
|
|
- if (!pipefp)
|
|
- pfatal ("Can't open pipe to %s", quotearg (buf));
|
|
- }
|
|
for (;;) {
|
|
char ed_command_letter;
|
|
beginning_of_this_line = file_tell (pfp);
|
|
@@ -2415,14 +2422,14 @@ do_ed_script (char const *inname, char c
|
|
}
|
|
ed_command_letter = get_ed_command_letter (buf);
|
|
if (ed_command_letter) {
|
|
- if (pipefp)
|
|
- if (! fwrite (buf, sizeof *buf, chars_read, pipefp))
|
|
+ if (tmpfp)
|
|
+ if (! fwrite (buf, sizeof *buf, chars_read, tmpfp))
|
|
write_fatal ();
|
|
if (ed_command_letter != 'd' && ed_command_letter != 's') {
|
|
p_pass_comments_through = true;
|
|
while ((chars_read = get_line ()) != 0) {
|
|
- if (pipefp)
|
|
- if (! fwrite (buf, sizeof *buf, chars_read, pipefp))
|
|
+ if (tmpfp)
|
|
+ if (! fwrite (buf, sizeof *buf, chars_read, tmpfp))
|
|
write_fatal ();
|
|
if (chars_read == 2 && strEQ (buf, ".\n"))
|
|
break;
|
|
@@ -2435,13 +2442,49 @@ do_ed_script (char const *inname, char c
|
|
break;
|
|
}
|
|
}
|
|
- if (!pipefp)
|
|
+ if (!tmpfp)
|
|
return;
|
|
- if (fwrite ("w\nq\n", sizeof (char), (size_t) 4, pipefp) == 0
|
|
- || fflush (pipefp) != 0)
|
|
+ if (fwrite ("w\nq\n", sizeof (char), (size_t) 4, tmpfp) == 0
|
|
+ || fflush (tmpfp) != 0)
|
|
write_fatal ();
|
|
- if (pclose (pipefp) != 0)
|
|
- fatal ("%s FAILED", editor_program);
|
|
+
|
|
+ if (lseek (tmpfd, 0, SEEK_SET) == -1)
|
|
+ pfatal ("Can't rewind to the beginning of file %s", quotearg (tmpname));
|
|
+
|
|
+ if (! dry_run && ! skip_rest_of_patch) {
|
|
+ int exclusive = *outname_needs_removal ? 0 : O_EXCL;
|
|
+ *outname_needs_removal = true;
|
|
+ if (inerrno != ENOENT)
|
|
+ {
|
|
+ *outname_needs_removal = true;
|
|
+ copy_file (inname, outname, 0, exclusive, instat.st_mode, true);
|
|
+ }
|
|
+ sprintf (buf, "%s %s%s", editor_program,
|
|
+ verbosity == VERBOSE ? "" : "- ",
|
|
+ outname);
|
|
+ fflush (stdout);
|
|
+
|
|
+ pid = fork();
|
|
+ if (pid == -1)
|
|
+ pfatal ("Can't fork");
|
|
+ else if (pid == 0)
|
|
+ {
|
|
+ dup2 (tmpfd, 0);
|
|
+ execl ("/bin/sh", "sh", "-c", buf, (char *) 0);
|
|
+ _exit (2);
|
|
+ }
|
|
+ else
|
|
+ {
|
|
+ int wstatus;
|
|
+ if (waitpid (pid, &wstatus, 0) == -1
|
|
+ || ! WIFEXITED (wstatus)
|
|
+ || WEXITSTATUS (wstatus) != 0)
|
|
+ fatal ("%s FAILED", editor_program);
|
|
+ }
|
|
+ }
|
|
+
|
|
+ fclose (tmpfp);
|
|
+ safe_unlink (tmpname);
|
|
|
|
if (ofp)
|
|
{
|