git: fix CVE-2023-25652

Git is a revision control system. Prior to versions 2.30.9, 2.31.8, 2.32.7,
2.33.8, 2.34.8, 2.35.8, 2.36.6, 2.37.7, 2.38.5, 2.39.3, and 2.40.1, by feeding
specially crafted input to `git apply --reject`, a path outside the working
tree can be overwritten with partially controlled contents (corresponding to
the rejected hunk(s) from the given patch). A fix is available in versions
2.30.9, 2.31.8, 2.32.7, 2.33.8, 2.34.8, 2.35.8, 2.36.6, 2.37.7, 2.38.5, 2.39.3,
and 2.40.1. As a workaround, avoid using `git apply` with `--reject` when applying
patches from an untrusted source. Use `git apply --stat` to inspect a patch before
applying; avoid applying one that create a conflict where a link corresponding to
the `*.rej` file exists.

References:
https://nvd.nist.gov/vuln/detail/CVE-2023-25652

Upstream-Status: Backport from https://github.com/git/git/commit/9db05711c98efc14f414d4c87135a34c13586e0b

(From OE-Core rev: 6747482316b8f7839a09bf041d8c11b559f84b44)

Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 95 insertions, 0 deletions

diff --git a/meta/recipes-devtools/git/files/CVE-2023-25652.patch b/meta/recipes-devtools/git/files/CVE-2023-25652.patch
new file mode 100644
index 0000000000..d6b17a2b8a
--- /dev/null
+++ b/meta/recipes-devtools/git/files/CVE-2023-25652.patch
@@ -0,0 +1,94 @@
+From 9db05711c98efc14f414d4c87135a34c13586e0b Mon Sep 17 00:00:00 2001
+From: Johannes Schindelin <johannes.schindelin@gmx.de>
+Date: Thu, 9 Mar 2023 16:02:54 +0100
+Subject: [PATCH] apply --reject: overwrite existing `.rej` symlink if it
+ exists
+
+The `git apply --reject` is expected to write out `.rej` files in case
+one or more hunks fail to apply cleanly. Historically, the command
+overwrites any existing `.rej` files. The idea being that
+apply/reject/edit cycles are relatively common, and the generated `.rej`
+files are not considered precious.
+
+But the command does not overwrite existing `.rej` symbolic links, and
+instead follows them. This is unsafe because the same patch could
+potentially create such a symbolic link and point at arbitrary paths
+outside the current worktree, and `git apply` would write the contents
+of the `.rej` file into that location.
+
+Therefore, let's make sure that any existing `.rej` file or symbolic
+link is removed before writing it.
+
+Reported-by: RyotaK <ryotak.mail@gmail.com>
+Helped-by: Taylor Blau <me@ttaylorr.com>
+Helped-by: Junio C Hamano <gitster@pobox.com>
+Helped-by: Linus Torvalds <torvalds@linuxfoundation.org>
+Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
+
+Upstream-Status: Backport [https://github.com/git/git/commit/9db05711c98efc14f414d4c87135a34c13586e0b]
+CVE: CVE-2023-25652
+Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
+---
+ apply.c                  | 14 ++++++++++++--
+ t/t4115-apply-symlink.sh | 15 +++++++++++++++
+ 2 files changed, 27 insertions(+), 2 deletions(-)
+
+diff --git a/apply.c b/apply.c
+index 4f303bf..aa7111d 100644
+--- a/apply.c
++++ b/apply.c
+@@ -4531,7 +4531,7 @@ static int write_out_one_reject(struct apply_state *state, struct patch *patch)
+        FILE *rej;
+        char namebuf[PATH_MAX];
+        struct fragment *frag;
+-       int cnt = 0;
++       int fd, cnt = 0;
+        struct strbuf sb = STRBUF_INIT;
+ 
+        for (cnt = 0, frag = patch->fragments; frag; frag = frag->next) {
+@@ -4571,7 +4571,17 @@ static int write_out_one_reject(struct apply_state *state, struct patch *patch)
+        memcpy(namebuf, patch->new_name, cnt);
+        memcpy(namebuf + cnt, ".rej", 5);
+ 
+-       rej = fopen(namebuf, "w");
++       fd = open(namebuf, O_CREAT | O_EXCL | O_WRONLY, 0666);
++       if (fd < 0) {
++               if (errno != EEXIST)
++                       return error_errno(_("cannot open %s"), namebuf);
++               if (unlink(namebuf))
++                       return error_errno(_("cannot unlink '%s'"), namebuf);
++               fd = open(namebuf, O_CREAT | O_EXCL | O_WRONLY, 0666);
++               if (fd < 0)
++                       return error_errno(_("cannot open %s"), namebuf);
++       }
++       rej = fdopen(fd, "w");
+        if (!rej)
+                return error_errno(_("cannot open %s"), namebuf);
+ 
+diff --git a/t/t4115-apply-symlink.sh b/t/t4115-apply-symlink.sh
+index 1acb7b2..2b034ff 100755
+--- a/t/t4115-apply-symlink.sh
++++ b/t/t4115-apply-symlink.sh
+@@ -125,4 +125,19 @@ test_expect_success SYMLINKS 'symlink escape when deleting file' '
+        test_path_is_file .git/delete-me
+ '
+ 
++test_expect_success SYMLINKS '--reject removes .rej symlink if it exists' '
++       test_when_finished "git reset --hard && git clean -dfx" &&
++
++       test_commit file &&
++       echo modified >file.t &&
++       git diff -- file.t >patch &&
++       echo modified-again >file.t &&
++
++       ln -s foo file.t.rej &&
++       test_must_fail git apply patch --reject 2>err &&
++       test_i18ngrep "Rejected hunk" err &&
++       test_path_is_missing foo &&
++       test_path_is_file file.t.rej
++'
++
+ test_done
+-- 
+2.25.1
+
diff --git a/meta/recipes-devtools/git/git.inc b/meta/recipes-devtools/git/git.inc
index 8b864053eb..e64472ea28 100644
--- a/meta/recipes-devtools/git/git.inc
+++ b/meta/recipes-devtools/git/git.inc
@@ -29,6 +29,7 @@ SRC_URI = "${KERNELORG_MIRROR}/software/scm/git/git-${PV}.tar.gz;name=tarball \
            file://CVE-2023-22490-3.patch \
            file://CVE-2023-23946.patch \
            file://CVE-2023-29007.patch \
+           file://CVE-2023-25652.patch \
            "
 S = "${WORKDIR}/git-${PV}"