grub: fix a dangling memory pointer

This change fixes a dangling memory pointer in the grub TFTP code.
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: 17a06ced4ed9305e0a4064bdaad49e653c18284b)

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, 34 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/0003-net-tftp-Fix-dangling-memory-pointer.patch b/meta/recipes-bsp/grub/files/0003-net-tftp-Fix-dangling-memory-pointer.patch
new file mode 100644
index 0000000000..3b4633507d
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/0003-net-tftp-Fix-dangling-memory-pointer.patch
@@ -0,0 +1,33 @@
+From 09cc0df477758b60f51fbc0da1dee2f5d54c333d Mon Sep 17 00:00:00 2001
+From: Darren Kenny <darren.kenny@oracle.com>
+Date: Fri, 19 Feb 2021 17:12:23 +0000
+Subject: [PATCH] net/tftp: Fix dangling memory pointer
+
+The static code analysis tool, Parfait, reported that the valid of
+file->data was left referencing memory that was freed by the call to
+grub_free(data) where data was initialized from file->data.
+
+To ensure that there is no unintentional access to this memory
+referenced by file->data we should set the pointer to NULL.
+
+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=0cb838b281a68b536a09681f9557ea6a7ac5da7a]
+Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
+---
+ grub-core/net/tftp.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/grub-core/net/tftp.c b/grub-core/net/tftp.c
+index 7d90bf6..f76b19f 100644
+--- a/grub-core/net/tftp.c
++++ b/grub-core/net/tftp.c
+@@ -468,6 +468,7 @@ tftp_close (struct grub_file *file)
+     }
+   destroy_pq (data);
+   grub_free (data);
++  file->data = NULL;
+   return GRUB_ERR_NONE;
+ }
+ 
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index 2c0bff8fd0..678aa5c4e2 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -49,6 +49,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://CVE-2020-25647.patch \
            file://0001-mmap-Fix-memory-leak-when-iterating-over-mapped-memo.patch \
            file://0002-net-net-Fix-possible-dereference-to-of-a-NULL-pointe.patch \
+           file://0003-net-tftp-Fix-dangling-memory-pointer.patch \
            "
 SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
 SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"