1From 123eaff0d5d1aebe128295959435b9ca5909c26d Mon Sep 17 00:00:00 2001 2From: Andreas Gruenbacher <agruen@gnu.org> 3Date: Fri, 6 Apr 2018 12:14:49 +0200 4Subject: [PATCH] Fix arbitrary command execution in ed-style patches (CVE-2018-1000156) 5 6* src/pch.c (do_ed_script): Write ed script to a temporary file instead 7of piping it to ed: this will cause ed to abort on invalid commands 8instead of rejecting them and carrying on. 9* tests/ed-style: New test case. 10* tests/Makefile.am (TESTS): Add test case. 11 12Upstream-Status: Backport [http://git.savannah.gnu.org/cgit/patch.git/commit/?id=123eaff0d5d1aebe128295959435b9ca5909c26d] 13CVE: CVE-2018-1000156 14 15Signed-off-by: Jackie Huang <jackie.huang@windriver.com> 16--- 17 src/pch.c | 91 ++++++++++++++++++++++++++++++++++++++++--------------- 18 tests/Makefile.am | 1 + 19 tests/ed-style | 41 +++++++++++++++++++++++++ 20 3 files changed, 108 insertions(+), 25 deletions(-) 21 create mode 100644 tests/ed-style 22 23diff --git a/src/pch.c b/src/pch.c 24index 0c5cc26..4fd5a05 100644 25--- a/src/pch.c 26+++ b/src/pch.c 27@@ -33,6 +33,7 @@ 28 # include <io.h> 29 #endif 30 #include <safe.h> 31+#include <sys/wait.h> 32 33 #define INITHUNKMAX 125 /* initial dynamic allocation size */ 34 35@@ -2389,24 +2390,28 @@ do_ed_script (char const *inname, char const *outname, 36 static char const editor_program[] = EDITOR_PROGRAM; 37 38 file_offset beginning_of_this_line; 39- FILE *pipefp = 0; 40 size_t chars_read; 41+ FILE *tmpfp = 0; 42+ char const *tmpname; 43+ int tmpfd; 44+ pid_t pid; 45+ 46+ if (! dry_run && ! skip_rest_of_patch) 47+ { 48+ /* Write ed script to a temporary file. This causes ed to abort on 49+ invalid commands such as when line numbers or ranges exceed the 50+ number of available lines. When ed reads from a pipe, it rejects 51+ invalid commands and treats the next line as a new command, which 52+ can lead to arbitrary command execution. */ 53+ 54+ tmpfd = make_tempfile (&tmpname, 'e', NULL, O_RDWR | O_BINARY, 0); 55+ if (tmpfd == -1) 56+ pfatal ("Can't create temporary file %s", quotearg (tmpname)); 57+ tmpfp = fdopen (tmpfd, "w+b"); 58+ if (! tmpfp) 59+ pfatal ("Can't open stream for file %s", quotearg (tmpname)); 60+ } 61 62- if (! dry_run && ! skip_rest_of_patch) { 63- int exclusive = *outname_needs_removal ? 0 : O_EXCL; 64- if (inerrno != ENOENT) 65- { 66- *outname_needs_removal = true; 67- copy_file (inname, outname, 0, exclusive, instat.st_mode, true); 68- } 69- sprintf (buf, "%s %s%s", editor_program, 70- verbosity == VERBOSE ? "" : "- ", 71- outname); 72- fflush (stdout); 73- pipefp = popen(buf, binary_transput ? "wb" : "w"); 74- if (!pipefp) 75- pfatal ("Can't open pipe to %s", quotearg (buf)); 76- } 77 for (;;) { 78 char ed_command_letter; 79 beginning_of_this_line = file_tell (pfp); 80@@ -2417,14 +2422,14 @@ do_ed_script (char const *inname, char const *outname, 81 } 82 ed_command_letter = get_ed_command_letter (buf); 83 if (ed_command_letter) { 84- if (pipefp) 85- if (! fwrite (buf, sizeof *buf, chars_read, pipefp)) 86+ if (tmpfp) 87+ if (! fwrite (buf, sizeof *buf, chars_read, tmpfp)) 88 write_fatal (); 89 if (ed_command_letter != 'd' && ed_command_letter != 's') { 90 p_pass_comments_through = true; 91 while ((chars_read = get_line ()) != 0) { 92- if (pipefp) 93- if (! fwrite (buf, sizeof *buf, chars_read, pipefp)) 94+ if (tmpfp) 95+ if (! fwrite (buf, sizeof *buf, chars_read, tmpfp)) 96 write_fatal (); 97 if (chars_read == 2 && strEQ (buf, ".\n")) 98 break; 99@@ -2437,13 +2442,49 @@ do_ed_script (char const *inname, char const *outname, 100 break; 101 } 102 } 103- if (!pipefp) 104+ if (!tmpfp) 105 return; 106- if (fwrite ("w\nq\n", sizeof (char), (size_t) 4, pipefp) == 0 107- || fflush (pipefp) != 0) 108+ if (fwrite ("w\nq\n", sizeof (char), (size_t) 4, tmpfp) == 0 109+ || fflush (tmpfp) != 0) 110 write_fatal (); 111- if (pclose (pipefp) != 0) 112- fatal ("%s FAILED", editor_program); 113+ 114+ if (lseek (tmpfd, 0, SEEK_SET) == -1) 115+ pfatal ("Can't rewind to the beginning of file %s", quotearg (tmpname)); 116+ 117+ if (! dry_run && ! skip_rest_of_patch) { 118+ int exclusive = *outname_needs_removal ? 0 : O_EXCL; 119+ *outname_needs_removal = true; 120+ if (inerrno != ENOENT) 121+ { 122+ *outname_needs_removal = true; 123+ copy_file (inname, outname, 0, exclusive, instat.st_mode, true); 124+ } 125+ sprintf (buf, "%s %s%s", editor_program, 126+ verbosity == VERBOSE ? "" : "- ", 127+ outname); 128+ fflush (stdout); 129+ 130+ pid = fork(); 131+ if (pid == -1) 132+ pfatal ("Can't fork"); 133+ else if (pid == 0) 134+ { 135+ dup2 (tmpfd, 0); 136+ execl ("/bin/sh", "sh", "-c", buf, (char *) 0); 137+ _exit (2); 138+ } 139+ else 140+ { 141+ int wstatus; 142+ if (waitpid (pid, &wstatus, 0) == -1 143+ || ! WIFEXITED (wstatus) 144+ || WEXITSTATUS (wstatus) != 0) 145+ fatal ("%s FAILED", editor_program); 146+ } 147+ } 148+ 149+ fclose (tmpfp); 150+ safe_unlink (tmpname); 151 152 if (ofp) 153 { 154diff --git a/tests/Makefile.am b/tests/Makefile.am 155index 6b6df63..16f8693 100644 156--- a/tests/Makefile.am 157+++ b/tests/Makefile.am 158@@ -32,6 +32,7 @@ TESTS = \ 159 crlf-handling \ 160 dash-o-append \ 161 deep-directories \ 162+ ed-style \ 163 empty-files \ 164 false-match \ 165 fifo \ 166diff --git a/tests/ed-style b/tests/ed-style 167new file mode 100644 168index 0000000..d8c0689 169--- /dev/null 170+++ b/tests/ed-style 171@@ -0,0 +1,41 @@ 172+# Copyright (C) 2018 Free Software Foundation, Inc. 173+# 174+# Copying and distribution of this file, with or without modification, 175+# in any medium, are permitted without royalty provided the copyright 176+# notice and this notice are preserved. 177+ 178+. $srcdir/test-lib.sh 179+ 180+require cat 181+use_local_patch 182+use_tmpdir 183+ 184+# ============================================================== 185+ 186+cat > ed1.diff <<EOF 187+0a 188+foo 189+. 190+EOF 191+ 192+check 'patch -e foo -i ed1.diff' <<EOF 193+EOF 194+ 195+check 'cat foo' <<EOF 196+foo 197+EOF 198+ 199+cat > ed2.diff <<EOF 200+1337a 201+r !echo bar 202+,p 203+EOF 204+ 205+check 'patch -e foo -i ed2.diff 2> /dev/null || echo "Status: $?"' <<EOF 206+? 207+Status: 2 208+EOF 209+ 210+check 'cat foo' <<EOF 211+foo 212+EOF 213-- 2142.7.4 215 216