rsync: fix CVE-2024-12088

A flaw was found in rsync. When using the `--safe-links` option, rsync fails to
properly verify if a symbolic link destination contains another symbolic link within it.
This results in a path traversal vulnerability, which may lead to arbitrary file write
outside the desired directory.

(From OE-Core rev: dad4a83c011310872cce07fc4141e66a98439cb1)

Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 142 insertions, 0 deletions

diff --git a/meta/recipes-devtools/rsync/files/CVE-2024-12088.patch b/meta/recipes-devtools/rsync/files/CVE-2024-12088.patch
new file mode 100644
index 0000000000..b2a3a86e1a
--- /dev/null
+++ b/meta/recipes-devtools/rsync/files/CVE-2024-12088.patch
@@ -0,0 +1,141 @@
+From 407c71c7ce562137230e8ba19149c81ccc47c387 Mon Sep 17 00:00:00 2001
+From: Andrew Tridgell <andrew@tridgell.net>
+Date: Sat, 23 Nov 2024 15:15:53 +1100
+Subject: [PATCH] make --safe-links stricter
+
+when --safe-links is used also reject links where a '../' component is
+included in the destination as other than the leading part of the
+filename
+
+CVE: CVE-2024-12088
+
+Upstream-Status: Backport [https://git.samba.org/?p=rsync.git;a=commit;h=407c71c7ce562137230e8ba19149c81ccc47c387]
+
+Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
+---
+ testsuite/safe-links.test    | 55 ++++++++++++++++++++++++++++++++++++
+ testsuite/unsafe-byname.test |  2 +-
+ util1.c                      | 26 ++++++++++++++++-
+ 3 files changed, 81 insertions(+), 2 deletions(-)
+ create mode 100644 testsuite/safe-links.test
+
+diff --git a/testsuite/safe-links.test b/testsuite/safe-links.test
+new file mode 100644
+index 00000000..6e95a4b9
+--- /dev/null
++++ b/testsuite/safe-links.test
+@@ -0,0 +1,55 @@
++#!/bin/sh
++
++. "$suitedir/rsync.fns"
++
++test_symlink() {
++       is_a_link "$1" || test_fail "File $1 is not a symlink"
++}
++
++test_regular() {
++       if [ ! -f "$1" ]; then
++               test_fail "File $1 is not regular file or not exists"
++       fi
++}
++
++test_notexist() {
++        if [ -e "$1" ]; then
++                test_fail "File $1 exists"
++       fi
++        if [ -h "$1" ]; then
++                test_fail "File $1 exists as a symlink"
++       fi
++}
++
++cd "$tmpdir"
++
++mkdir from
++
++mkdir "from/safe"
++mkdir "from/unsafe"
++
++mkdir "from/safe/files"
++mkdir "from/safe/links"
++
++touch "from/safe/files/file1"
++touch "from/safe/files/file2"
++touch "from/unsafe/unsafefile"
++
++ln -s ../files/file1 "from/safe/links/"
++ln -s ../files/file2 "from/safe/links/"
++ln -s ../../unsafe/unsafefile "from/safe/links/"
++ln -s a/a/a/../../../unsafe2 "from/safe/links/"
++
++#echo "LISTING FROM"
++#ls -lR from
++
++echo "rsync with relative path and just -a"
++$RSYNC -avv --safe-links from/safe/ to
++
++#echo "LISTING TO"
++#ls -lR to
++
++test_symlink to/links/file1
++test_symlink to/links/file2
++test_notexist to/links/unsafefile
++test_notexist to/links/unsafe2
+diff --git a/testsuite/unsafe-byname.test b/testsuite/unsafe-byname.test
+index 75e72014..d2e318ef 100644
+--- a/testsuite/unsafe-byname.test
++++ b/testsuite/unsafe-byname.test
+@@ -40,7 +40,7 @@ test_unsafe ..//../dest               from/dir                        unsafe
+ test_unsafe ..                         from/file                       safe
+ test_unsafe ../..                      from/file                       unsafe
+ test_unsafe ..//..                     from//file                      unsafe
+-test_unsafe dir/..                     from                            safe
++test_unsafe dir/..                     from                            unsafe
+ test_unsafe dir/../..                  from                            unsafe
+ test_unsafe dir/..//..                 from                            unsafe
+
+diff --git a/util1.c b/util1.c
+index da50ff1e..f260d398 100644
+--- a/util1.c
++++ b/util1.c
+@@ -1318,7 +1318,14 @@ int handle_partial_dir(const char *fname, int create)
+  *
+  * "src" is the top source directory currently applicable at the level
+  * of the referenced symlink.  This is usually the symlink's full path
+- * (including its name), as referenced from the root of the transfer. */
++ * (including its name), as referenced from the root of the transfer.
++ *
++ * NOTE: this also rejects dest names with a .. component in other
++ * than the first component of the name ie. it rejects names such as
++ * a/b/../x/y. This needs to be done as the leading subpaths 'a' or
++ * 'b' could later be replaced with symlinks such as a link to '.'
++ * resulting in the link being transferred now becoming unsafe
++ */
+ int unsafe_symlink(const char *dest, const char *src)
+ {
+        const char *name, *slash;
+@@ -1328,6 +1335,23 @@ int unsafe_symlink(const char *dest, const char *src)
+        if (!dest || !*dest || *dest == '/')
+                return 1;
+
++       // reject destinations with /../ in the name other than at the start of the name
++       const char *dest2 = dest;
++       while (strncmp(dest2, "../", 3) == 0) {
++           dest2 += 3;
++           while (*dest2 == '/') {
++               // allow for ..//..///../foo
++               dest2++;
++           }
++       }
++       if (strstr(dest2, "/../"))
++           return 1;
++
++       // reject if the destination ends in /..
++       const size_t dlen = strlen(dest);
++       if (dlen > 3 && strcmp(&dest[dlen-3], "/..") == 0)
++           return 1;
++
+        /* find out what our safety margin is */
+        for (name = src; (slash = strchr(name, '/')) != 0; name = slash+1) {
+                /* ".." segment starts the count over.  "." segment is ignored. */
+--
+2.40.0
diff --git a/meta/recipes-devtools/rsync/rsync_3.2.7.bb b/meta/recipes-devtools/rsync/rsync_3.2.7.bb
index d6942dc595..169650fe91 100644
--- a/meta/recipes-devtools/rsync/rsync_3.2.7.bb
+++ b/meta/recipes-devtools/rsync/rsync_3.2.7.bb
@@ -25,6 +25,7 @@ SRC_URI = "https://download.samba.org/pub/${BPN}/src/${BP}.tar.gz \
            file://CVE-2024-12087-0001.patch \
            file://CVE-2024-12087-0002.patch \
            file://CVE-2024-12087-0003.patch \
+           file://CVE-2024-12088.patch \
            "
 SRC_URI[sha256sum] = "4e7d9d3f6ed10878c58c5fb724a67dacf4b6aac7340b13e488fb2dc41346f2bb"