grub: add a check for a NULL pointer

This patch adds a check for a NULL pointer before use in grub's
loader/xnu. It is a part of a security series [1].

[1] https://lists.gnu.org/archive/html/grub-devel/2021-03/msg00007.html

(From OE-Core rev: 1d95061ecdc920835df44c0c3ed274193f26948e)

Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 43 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/0040-loader-xnu-Check-if-pointer-is-NULL-before-using-it.patch b/meta/recipes-bsp/grub/files/0040-loader-xnu-Check-if-pointer-is-NULL-before-using-it.patch
new file mode 100644
index 0000000000..8081f7763a
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/0040-loader-xnu-Check-if-pointer-is-NULL-before-using-it.patch
@@ -0,0 +1,42 @@
+From 778a3fffd19229e5650a1abfb06c974949991cd4 Mon Sep 17 00:00:00 2001
+From: Paulo Flabiano Smorigo <pfsmorigo@canonical.com>
+Date: Mon, 30 Nov 2020 10:36:00 -0300
+Subject: [PATCH] loader/xnu: Check if pointer is NULL before using it
+
+Fixes: CID 73654
+
+Signed-off-by: Paulo Flabiano Smorigo <pfsmorigo@canonical.com>
+Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
+
+Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=7c8a2b5d1421a0f2a33d33531f7561f3da93b844]
+Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
+---
+ grub-core/loader/xnu.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/grub-core/loader/xnu.c b/grub-core/loader/xnu.c
+index 39ceff8..adc048c 100644
+--- a/grub-core/loader/xnu.c
++++ b/grub-core/loader/xnu.c
+@@ -667,6 +667,9 @@ grub_xnu_load_driver (char *infoplistname, grub_file_t binaryfile,
+   char *name, *nameend;
+   int namelen;
+ 
++  if (infoplistname == NULL)
++    return grub_error (GRUB_ERR_BAD_FILENAME, N_("missing p-list filename"));
++
+   name = get_name_ptr (infoplistname);
+   nameend = grub_strchr (name, '/');
+ 
+@@ -698,10 +701,7 @@ grub_xnu_load_driver (char *infoplistname, grub_file_t binaryfile,
+   else
+     macho = 0;
+ 
+-  if (infoplistname)
+-    infoplist = grub_file_open (infoplistname, GRUB_FILE_TYPE_XNU_INFO_PLIST);
+-  else
+-    infoplist = 0;
++  infoplist = grub_file_open (infoplistname, GRUB_FILE_TYPE_XNU_INFO_PLIST);
+   grub_errno = GRUB_ERR_NONE;
+   if (infoplist)
+     {
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index eebe9a7233..fad7415e0d 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -86,6 +86,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://0037-loader-bsd-Check-for-NULL-arg-up-front.patch \
            file://0038-loader-xnu-Fix-memory-leak.patch \
            file://0039-loader-xnu-Free-driverkey-data-when-an-error-is-dete.patch \
+           file://0040-loader-xnu-Check-if-pointer-is-NULL-before-using-it.patch \
            "
 SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
 SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"