grub: add a fix for possible integer overflows

This patch adds a fix for a possible integer overflows in grub's zfs.
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: a21a1f225090b2f9d4c76e323fa7cc2051587924)

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, 57 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/0023-zfs-Fix-possible-integer-overflows.patch b/meta/recipes-bsp/grub/files/0023-zfs-Fix-possible-integer-overflows.patch
new file mode 100644
index 0000000000..8df758b41f
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/0023-zfs-Fix-possible-integer-overflows.patch
@@ -0,0 +1,56 @@
+From ec35d862f3567671048aa0d0d8ad1ded1fd25336 Mon Sep 17 00:00:00 2001
+From: Darren Kenny <darren.kenny@oracle.com>
+Date: Tue, 8 Dec 2020 22:17:04 +0000
+Subject: [PATCH] zfs: Fix possible integer overflows
+
+In all cases the problem is that the value being acted upon by
+a left-shift is a 32-bit number which is then being used in the
+context of a 64-bit number.
+
+To avoid overflow we ensure that the number being shifted is 64-bit
+before the shift is done.
+
+Fixes: CID 73684, CID 73695, CID 73764
+
+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=302c12ff5714bc455949117c1c9548ccb324d55b]
+Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
+---
+ grub-core/fs/zfs/zfs.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/grub-core/fs/zfs/zfs.c b/grub-core/fs/zfs/zfs.c
+index 9087a72..b078ccc 100644
+--- a/grub-core/fs/zfs/zfs.c
++++ b/grub-core/fs/zfs/zfs.c
+@@ -564,7 +564,7 @@ find_bestub (uberblock_phys_t * ub_array,
+       ubptr = (uberblock_phys_t *) ((grub_properly_aligned_t *) ub_array
+                                    + ((i << ub_shift)
+                                       / sizeof (grub_properly_aligned_t)));
+-      err = uberblock_verify (ubptr, offset, 1 << ub_shift);
++      err = uberblock_verify (ubptr, offset, (grub_size_t) 1 << ub_shift);
+       if (err)
+        {
+          grub_errno = GRUB_ERR_NONE;
+@@ -1543,7 +1543,7 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
+ 
+            high = grub_divmod64 ((offset >> desc->ashift) + c,
+                                  desc->n_children, &devn);
+-           csize = bsize << desc->ashift;
++           csize = (grub_size_t) bsize << desc->ashift;
+            if (csize > len)
+              csize = len;
+ 
+@@ -1635,8 +1635,8 @@ read_device (grub_uint64_t offset, struct grub_zfs_device_desc *desc,
+ 
+            while (len > 0)
+              {
+-               grub_size_t csize;
+-               csize = ((s / (desc->n_children - desc->nparity))
++               grub_size_t csize = s;
++               csize = ((csize / (desc->n_children - desc->nparity))
+                         << desc->ashift);
+                if (csize > len)
+                  csize = len;
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index 1630235edd..9158fc7f50 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -69,6 +69,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://0020-hfsplus-Check-that-the-volume-name-length-is-valid.patch \
            file://0021-zfs-Fix-possible-negative-shift-operation.patch \
            file://0022-zfs-Fix-resource-leaks-while-constructing-path.patch \
+           file://0023-zfs-Fix-possible-integer-overflows.patch \
            "
 SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
 SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"