grub: add a fix for an incorrect cast

This patch adds a fix for incorrect casting from signed to unsigned
in grub's util/grub-editenv. 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: 906ecdc9efbc1b4025c2c7a9797ebd374f8508af)

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, 47 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/0042-util-grub-editenv-Fix-incorrect-casting-of-a-signed-.patch b/meta/recipes-bsp/grub/files/0042-util-grub-editenv-Fix-incorrect-casting-of-a-signed-.patch
new file mode 100644
index 0000000000..0cd8ec3611
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/0042-util-grub-editenv-Fix-incorrect-casting-of-a-signed-.patch
@@ -0,0 +1,46 @@
+From 3d68daf2567aace4b52bd238cfd4a8111af3bc04 Mon Sep 17 00:00:00 2001
+From: Darren Kenny <darren.kenny@oracle.com>
+Date: Thu, 5 Nov 2020 14:33:50 +0000
+Subject: [PATCH] util/grub-editenv: Fix incorrect casting of a signed value
+
+The return value of ftell() may be negative (-1) on error. While it is
+probably unlikely to occur, we should not blindly cast to an unsigned
+value without first testing that it is not negative.
+
+Fixes: CID 73856
+
+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=5dc41edc4eba259c6043ae7698c245ec1baaacc6]
+Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
+---
+ util/grub-editenv.c | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/util/grub-editenv.c b/util/grub-editenv.c
+index f3662c9..db6f187 100644
+--- a/util/grub-editenv.c
++++ b/util/grub-editenv.c
+@@ -125,6 +125,7 @@ open_envblk_file (const char *name)
+ {
+   FILE *fp;
+   char *buf;
++  long loc;
+   size_t size;
+   grub_envblk_t envblk;
+ 
+@@ -143,7 +144,12 @@ open_envblk_file (const char *name)
+     grub_util_error (_("cannot seek `%s': %s"), name,
+                     strerror (errno));
+ 
+-  size = (size_t) ftell (fp);
++  loc = ftell (fp);
++  if (loc < 0)
++    grub_util_error (_("cannot get file location `%s': %s"), name,
++                    strerror (errno));
++
++  size = (size_t) loc;
+ 
+   if (fseek (fp, 0, SEEK_SET) < 0)
+     grub_util_error (_("cannot seek `%s': %s"), name,
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index 7ca0b469e9..a1fbc5e644 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -88,6 +88,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            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 \
            file://0041-util-grub-install-Fix-NULL-pointer-dereferences.patch \
+           file://0042-util-grub-editenv-Fix-incorrect-casting-of-a-signed-.patch \
            "
 SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
 SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"