grub: add a missing NULL check

This fix adds a missing check for NULL pointer from an external source
in grub's kern/partition. 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: c443bd15c975d05ca7afc44e81bda1e974833e36)

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, 44 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/0015-kern-partition-Check-for-NULL-before-dereferencing-i.patch b/meta/recipes-bsp/grub/files/0015-kern-partition-Check-for-NULL-before-dereferencing-i.patch
new file mode 100644
index 0000000000..af9fcd45cc
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/0015-kern-partition-Check-for-NULL-before-dereferencing-i.patch
@@ -0,0 +1,43 @@
+From 0da8ef2e03a8591586b53a29af92d2ace76a04e3 Mon Sep 17 00:00:00 2001
+From: Darren Kenny <darren.kenny@oracle.com>
+Date: Fri, 23 Oct 2020 09:49:59 +0000
+Subject: [PATCH] kern/partition: Check for NULL before dereferencing input
+ string
+
+There is the possibility that the value of str comes from an external
+source and continuing to use it before ever checking its validity is
+wrong. So, needs fixing.
+
+Additionally, drop unneeded part initialization.
+
+Fixes: CID 292444
+
+Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
+Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
+
+Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=bc9c468a2ce84bc767234eec888b71f1bc744fff]
+Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
+---
+ grub-core/kern/partition.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/grub-core/kern/partition.c b/grub-core/kern/partition.c
+index e499147..b10a184 100644
+--- a/grub-core/kern/partition.c
++++ b/grub-core/kern/partition.c
+@@ -109,11 +109,14 @@ grub_partition_map_probe (const grub_partition_map_t partmap,
+ grub_partition_t
+ grub_partition_probe (struct grub_disk *disk, const char *str)
+ {
+-  grub_partition_t part = 0;
++  grub_partition_t part;
+   grub_partition_t curpart = 0;
+   grub_partition_t tail;
+   const char *ptr;
+ 
++  if (str == NULL)
++    return 0;
++
+   part = tail = disk->partition;
+ 
+   for (ptr = str; *ptr;)
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index 7cf4d64149..94b89aa643 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -61,6 +61,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://0012-gnulib-regcomp-Fix-uninitialized-re_token.patch \
            file://0013-io-lzopio-Resolve-unnecessary-self-assignment-errors.patch \
            file://0014-zstd-Initialize-seq_t-structure-fully.patch \
+           file://0015-kern-partition-Check-for-NULL-before-dereferencing-i.patch \
            "
 SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
 SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"