[Buildroot] [PATCH] patch: add upstream security fix
Baruch Siach
baruch at tkos.co.il
Mon Apr 9 16:20:36 UTC 2018
Fixes CVE-2018-1000156: arbitrary command execution in ed-style patches.
Depend on MMU for now, because the patch adds a fork() call. Upstream
later switched to gnulib provided execute(), so this dependency can be
dropped on the next version bump.
Signed-off-by: Baruch Siach <baruch at tkos.co.il>
---
...-files-to-be-missing-for-ed-style-patches.patch | 37 +++++
...ry-command-execution-in-ed-style-patches-.patch | 157 +++++++++++++++++++++
package/patch/Config.in | 2 +
3 files changed, 196 insertions(+)
create mode 100644 package/patch/0002-Allow-input-files-to-be-missing-for-ed-style-patches.patch
create mode 100644 package/patch/0003-Fix-arbitrary-command-execution-in-ed-style-patches-.patch
diff --git a/package/patch/0002-Allow-input-files-to-be-missing-for-ed-style-patches.patch b/package/patch/0002-Allow-input-files-to-be-missing-for-ed-style-patches.patch
new file mode 100644
index 000000000000..7d5757d1af8d
--- /dev/null
+++ b/package/patch/0002-Allow-input-files-to-be-missing-for-ed-style-patches.patch
@@ -0,0 +1,37 @@
+From b5a91a01e5d0897facdd0f49d64b76b0f02b43e1 Mon Sep 17 00:00:00 2001
+From: Andreas Gruenbacher <agruen at gnu.org>
+Date: Fri, 6 Apr 2018 11:34:51 +0200
+Subject: [PATCH] Allow input files to be missing for ed-style patches
+
+* src/pch.c (do_ed_script): Allow input files to be missing so that new
+files will be created as with non-ed-style patches.
+
+Signed-off-by: Baruch Siach <baruch at tkos.co.il>
+---
+Upstream status: commit b5a91a01e5d0
+
+ src/pch.c | 8 +++++---
+ 1 file changed, 5 insertions(+), 3 deletions(-)
+
+diff --git a/src/pch.c b/src/pch.c
+index bc6278c4032c..0c5cc2623079 100644
+--- a/src/pch.c
++++ b/src/pch.c
+@@ -2394,9 +2394,11 @@ do_ed_script (char const *inname, char const *outname,
+
+ 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);
++ 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);
+--
+2.16.3
+
diff --git a/package/patch/0003-Fix-arbitrary-command-execution-in-ed-style-patches-.patch b/package/patch/0003-Fix-arbitrary-command-execution-in-ed-style-patches-.patch
new file mode 100644
index 000000000000..b44bdd0faca7
--- /dev/null
+++ b/package/patch/0003-Fix-arbitrary-command-execution-in-ed-style-patches-.patch
@@ -0,0 +1,157 @@
+From 123eaff0d5d1aebe128295959435b9ca5909c26d Mon Sep 17 00:00:00 2001
+From: Andreas Gruenbacher <agruen at 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.
+
+[baruch: drop test hunks to avoid autoreconf]
+Signed-off-by: Baruch Siach <baruch at tkos.co.il>
+---
+Upstream status: commit 123eaff0d5d1
+
+ src/pch.c | 91 ++++++++++++++++++++++++++++++++++++++++---------------
+ tests/Makefile.am | 1 +
+ tests/ed-style | 41 +++++++++++++++++++++++++
+ 3 files changed, 108 insertions(+), 25 deletions(-)
+ create mode 100644 tests/ed-style
+
+diff --git a/src/pch.c b/src/pch.c
+index 0c5cc2623079..4fd5a05a6f5c 100644
+--- 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 */
+
+@@ -2389,24 +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)
++ {
++ /* 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;
+- 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);
+- 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);
+@@ -2417,14 +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;
+@@ -2437,13 +2442,49 @@ 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);
++ }
++ 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)
+ {
+--
+2.16.3
+
diff --git a/package/patch/Config.in b/package/patch/Config.in
index 0c2425823a26..13fa7bfc52ed 100644
--- a/package/patch/Config.in
+++ b/package/patch/Config.in
@@ -1,5 +1,6 @@
config BR2_PACKAGE_PATCH
bool "patch"
+ depends on BR2_USE_MMU # fork()
depends on BR2_USE_WCHAR
depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
help
@@ -10,4 +11,5 @@ config BR2_PACKAGE_PATCH
comment "patch needs a toolchain w/ wchar"
depends on !BR2_USE_WCHAR
+ depends on BR2_USE_MMU
depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
--
2.16.3
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