[OE-core] [PATCH 1/1] patch: fix CVE-2015-1196
Robert Yang
liezhi.yang at windriver.com
Thu Mar 26 06:42:34 UTC 2015
A directory traversal flaw was reported in patch:
References:
http://www.openwall.com/lists/oss-security/2015/01/18/6
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=775227
https://bugzilla.redhat.com/show_bug.cgi?id=1182154
[YOCTO #7182]
Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
meta/recipes-devtools/patch/patch.inc | 5 +-
.../patch/patch/patch-CVE-2015-1196.patch | 200 ++++++++++++++++++++
2 files changed, 204 insertions(+), 1 deletion(-)
create mode 100644 meta/recipes-devtools/patch/patch/patch-CVE-2015-1196.patch
diff --git a/meta/recipes-devtools/patch/patch.inc b/meta/recipes-devtools/patch/patch.inc
index 332b97a..d306403 100644
--- a/meta/recipes-devtools/patch/patch.inc
+++ b/meta/recipes-devtools/patch/patch.inc
@@ -4,7 +4,10 @@ produced by the diff program and applies those differences to one or more \
original files, producing patched versions."
SECTION = "utils"
-SRC_URI = "${GNU_MIRROR}/patch/patch-${PV}.tar.gz"
+SRC_URI = "${GNU_MIRROR}/patch/patch-${PV}.tar.gz \
+ file://patch-CVE-2015-1196.patch \
+ "
+
S = "${WORKDIR}/patch-${PV}"
inherit autotools update-alternatives
diff --git a/meta/recipes-devtools/patch/patch/patch-CVE-2015-1196.patch b/meta/recipes-devtools/patch/patch/patch-CVE-2015-1196.patch
new file mode 100644
index 0000000..d408346
--- /dev/null
+++ b/meta/recipes-devtools/patch/patch/patch-CVE-2015-1196.patch
@@ -0,0 +1,200 @@
+From 4e9269a5fc1fe80a1095a92593dd85db871e1fd3 Mon Sep 17 00:00:00 2001
+From: Andreas Gruenbacher <andreas.gruenbacher at gmail.com>
+Date: Mon, 19 Jan 2015 23:18:30 +0100
+Subject: [PATCH] Make sure symlinks don't point outside working directory
+ (CVE-2015-1196)
+
+When creating symlinks from git-style patches, make sure the symlinks don't
+point above the current working directory. Otherwise, a subsequent patch could
+use the symlink to write outside the working directory.
+
+* src/pch.c (symlink_target_is_valid): New function to check for valid symlink
+targets.
+* src/util.c (move_file): Use symlink_target_is_valid() here.
+* tests/symlinks: Add valid and invalid symlink test cases.
+
+Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
+
+Upstream-Status: Backport
+
+---
+ NEWS | 3 ++
+ src/pch.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ src/pch.h | 1 +
+ src/util.c | 7 +++++++
+ tests/symlinks | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
+ 5 files changed, 117 insertions(+)
+
+diff --git a/NEWS b/NEWS
+index 42afed7..d3f1c2d 100644
+--- a/NEWS
++++ b/NEWS
+@@ -1,3 +1,6 @@
++* With git-style patches, symlinks that point outside the working directory
++ will no longer be created.
++
+ Changes in version 2.7.1:
+
+ * Two critical bug fixes in the "diff --git" format support.
+diff --git a/src/pch.c b/src/pch.c
+index 55e1504..f05ef83 100644
+--- a/src/pch.c
++++ b/src/pch.c
+@@ -454,6 +454,60 @@ name_is_valid (char const *name)
+ return is_valid;
+ }
+
++bool
++symlink_target_is_valid (char const *target, char const *to)
++{
++ bool is_valid;
++
++ if (IS_ABSOLUTE_FILE_NAME (to))
++ is_valid = true;
++ else if (IS_ABSOLUTE_FILE_NAME (target))
++ is_valid = false;
++ else
++ {
++ unsigned int depth = 0;
++ char const *t;
++
++ is_valid = true;
++ t = to;
++ while (*t)
++ {
++ while (*t && ! ISSLASH (*t))
++ t++;
++ if (ISSLASH (*t))
++ {
++ while (ISSLASH (*t))
++ t++;
++ depth++;
++ }
++ }
++
++ t = target;
++ while (*t)
++ {
++ if (*t == '.' && *++t == '.' && (! *++t || ISSLASH (*t)))
++ {
++ if (! depth--)
++ {
++ is_valid = false;
++ break;
++ }
++ }
++ else
++ {
++ while (*t && ! ISSLASH (*t))
++ t++;
++ depth++;
++ }
++ while (ISSLASH (*t))
++ t++;
++ }
++ }
++
++ /* Allow any symlink target if we are in the filesystem root. */
++ return is_valid || cwd_is_root (to);
++}
++
+ /* Determine what kind of diff is in the remaining part of the patch file. */
+
+ static enum diff
+diff --git a/src/pch.h b/src/pch.h
+index 0c7ff62..58861b0 100644
+--- a/src/pch.h
++++ b/src/pch.h
+@@ -37,6 +37,7 @@ bool pch_write_line (lin, FILE *);
+ bool there_is_another_patch (bool, mode_t *);
+ char *pfetch (lin) _GL_ATTRIBUTE_PURE;
+ char pch_char (lin) _GL_ATTRIBUTE_PURE;
++bool symlink_target_is_valid (char const *, char const *);
+ int another_hunk (enum diff, bool);
+ int pch_says_nonexistent (bool) _GL_ATTRIBUTE_PURE;
+ size_t pch_line_len (lin) _GL_ATTRIBUTE_PURE;
+diff --git a/src/util.c b/src/util.c
+index 66ae90f..636eded 100644
+--- a/src/util.c
++++ b/src/util.c
+@@ -470,6 +470,13 @@ move_file (char const *from, bool *from_needs_removal,
+ read_fatal ();
+ buffer[size] = 0;
+
++ if (! symlink_target_is_valid (buffer, to))
++ {
++ fprintf (stderr, "symbolic link target '%s' is invalid\n",
++ buffer);
++ fatal_exit (0);
++ }
++
+ if (! backup)
+ {
+ if (unlink (to) == 0)
+diff --git a/tests/symlinks b/tests/symlinks
+index 96626b3..6211026 100644
+--- a/tests/symlinks
++++ b/tests/symlinks
+@@ -146,6 +146,59 @@ ncheck 'test ! -L symlink'
+
+ # --------------------------------------------------------------
+
++# Patch should not create symlinks which point outside the working directory.
++
++cat > symlink-target.diff <<EOF
++diff --git a/dir/foo b/dir/foo
++new file mode 120000
++index 0000000..cad2309
++--- /dev/null
+++++ b/dir/foo
++@@ -0,0 +1 @@
+++../foo
++\ No newline at end of file
++EOF
++
++check 'patch -p1 < symlink-target.diff || echo "Status: $?"' <<EOF
++patching symbolic link dir/foo
++EOF
++
++cat > bad-symlink-target1.diff <<EOF
++diff --git a/bar b/bar
++new file mode 120000
++index 0000000..cad2309
++--- /dev/null
+++++ b/bar
++@@ -0,0 +1 @@
+++/bar
++\ No newline at end of file
++EOF
++
++check 'patch -p1 < bad-symlink-target1.diff || echo "Status: $?"' <<EOF
++patching symbolic link bar
++symbolic link target '/bar' is invalid
++Status: 2
++EOF
++
++cat > bad-symlink-target2.diff <<EOF
++diff --git a/baz b/baz
++new file mode 120000
++index 0000000..cad2309
++--- /dev/null
+++++ b/baz
++@@ -0,0 +1 @@
+++../baz
++\ No newline at end of file
++EOF
++
++check 'patch -p1 < bad-symlink-target2.diff || echo "Status: $?"' <<EOF
++patching symbolic link baz
++symbolic link target '../baz' is invalid
++Status: 2
++EOF
++
++# --------------------------------------------------------------
++
+ # The backup file of a new symlink is an empty regular file.
+
+ check 'patch -p1 --backup < create-symlink.diff || echo "Status: $?"' <<EOF
+--
+2.1.4
+
--
1.7.9.5
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