Fix GNU patch CVE-2018-1000156

Index: Makefile
===================================================================
RCS file: /cvs/ports/devel/gpatch/Makefile,v
retrieving revision 1.10
diff -u -p -r1.10 Makefile
--- Makefile 16 Jul 2019 21:29:41 -0000 1.10
+++ Makefile 31 May 2020 01:05:37 -0000
@@ -6,7 +6,7 @@ VERSION= 2.7.6
DISTNAME= patch-${VERSION}
PKGNAME= gpatch-${VERSION}
CATEGORIES= devel
-REVISION= 0
+REVISION= 1

HOMEPAGE= https://www.gnu.org/software/patch/

Index: patches/patch-src_pch_c
===================================================================
RCS file: patches/patch-src_pch_c
diff -N patches/patch-src_pch_c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ patches/patch-src_pch_c 31 May 2020 01:05:37 -0000
@@ -0,0 +1,140 @@
+$OpenBSD$
+
+https://nvd.nist.gov/vuln/detail/CVE-2018-1000156
+
+Index: src/pch.c
+--- src/pch.c.orig
++++ 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 */
+
+@@ -974,7 +975,8 @@ intuit_diff_type (bool need_header, mode_t *p_file_typ
+ if ((pch_rename () || pch_copy ())
+ && ! inname
+ && ! ((i == OLD || i == NEW) &&
+- p_name[! reverse] &&
++ p_name[reverse] && p_name[! reverse] &&
++ name_is_valid (p_name[reverse]) &&
+ name_is_valid (p_name[! reverse])))
+ {
+ say ("Cannot %s file without two valid file names\n", pch_rename () ? "rename" : "copy");
+@@ -2388,22 +2390,28 @@ do_ed_script (char const *inname, char const *outname,
+ 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) {
+- 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));
+- }
++ 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));
++ }
++
+ for (;;) {
+ char ed_command_letter;
+ beginning_of_this_line = file_tell (pfp);
+@@ -2414,14 +2422,14 @@ do_ed_script (char const *inname, char const *outname,
+ }
+ 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;
+@@ -2434,13 +2442,47 @@ do_ed_script (char const *inname, char const *outname,
+ 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);
++ }
++ fflush (stdout);
++
++ pid = fork();
++ if (pid == -1)
++ pfatal ("Can't fork");
++ else if (pid == 0)
++ {
++ dup2 (tmpfd, 0);
++ assert (outname[0] != '!' && outname[0] != '-');
++ execlp (editor_program, editor_program, "-", outname, (char *) NULL);
++ _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)
+ {
Hi ports --

repology.org has a new feature where it tracks the CVEs against its
database of software. I decided to check it out to see if any of my
ports were vulnerable. I discovered that our GNU patch is vulnerable
to CVE-2018-1000156. It has been fixed upstream but no new release
has been made including the fix. So I cherry-picked it for our
package.

Upstream does have a test with it, but adding the test to the build
would bring in a dependency on autotools, so I left it out but I did
confirm that the test passes on amd64 and sparc64.

Tested on amd64 and sparc64. Additionally, on amd64 I built
everything that depends on gpatch. Libreoffice is still building;
will report back if it fails to build.

Should this be backported to -stable?

~Brian