grub: fix an integer overflow

This patch fixes a potential overflow in grub's disk/cryptodisk. 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: 85405f0d3a4b844f7bbb34717bd5f88b81acb074)

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, 51 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/0019-disk-cryptodisk-Fix-potential-integer-overflow.patch b/meta/recipes-bsp/grub/files/0019-disk-cryptodisk-Fix-potential-integer-overflow.patch
new file mode 100644
index 0000000000..dd7fda357d
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/0019-disk-cryptodisk-Fix-potential-integer-overflow.patch
@@ -0,0 +1,50 @@
+From 2550aaa0c23fdf8b6c54e00c6b838f2e3aa81fe2 Mon Sep 17 00:00:00 2001
+From: Darren Kenny <darren.kenny@oracle.com>
+Date: Thu, 21 Jan 2021 11:38:31 +0000
+Subject: [PATCH] disk/cryptodisk: Fix potential integer overflow
+
+The encrypt and decrypt functions expect a grub_size_t. So, we need to
+ensure that the constant bit shift is using grub_size_t rather than
+unsigned int when it is performing the shift.
+
+Fixes: CID 307788
+
+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=a201ad17caa430aa710654fdf2e6ab4c8166f031]
+Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
+---
+ grub-core/disk/cryptodisk.c | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
+index 5037768..6883f48 100644
+--- a/grub-core/disk/cryptodisk.c
++++ b/grub-core/disk/cryptodisk.c
+@@ -311,10 +311,10 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *dev,
+        case GRUB_CRYPTODISK_MODE_CBC:
+          if (do_encrypt)
+            err = grub_crypto_cbc_encrypt (dev->cipher, data + i, data + i,
+-                                          (1U << dev->log_sector_size), iv);
++                                          ((grub_size_t) 1 << dev->log_sector_size), iv);
+          else
+            err = grub_crypto_cbc_decrypt (dev->cipher, data + i, data + i,
+-                                          (1U << dev->log_sector_size), iv);
++                                          ((grub_size_t) 1 << dev->log_sector_size), iv);
+          if (err)
+            return err;
+          break;
+@@ -322,10 +322,10 @@ grub_cryptodisk_endecrypt (struct grub_cryptodisk *dev,
+        case GRUB_CRYPTODISK_MODE_PCBC:
+          if (do_encrypt)
+            err = grub_crypto_pcbc_encrypt (dev->cipher, data + i, data + i,
+-                                           (1U << dev->log_sector_size), iv);
++                                           ((grub_size_t) 1 << dev->log_sector_size), iv);
+          else
+            err = grub_crypto_pcbc_decrypt (dev->cipher, data + i, data + i,
+-                                           (1U << dev->log_sector_size), iv);
++                                           ((grub_size_t) 1 << dev->log_sector_size), iv);
+          if (err)
+            return err;
+          break;
diff --git a/meta/recipes-bsp/grub/grub2.inc b/meta/recipes-bsp/grub/grub2.inc
index 2fccdc2d62..130f32551b 100644
--- a/meta/recipes-bsp/grub/grub2.inc
+++ b/meta/recipes-bsp/grub/grub2.inc
@@ -65,6 +65,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://0016-disk-ldm-Make-sure-comp-data-is-freed-before-exiting.patch \
            file://0017-disk-ldm-If-failed-then-free-vg-variable-too.patch \
            file://0018-disk-ldm-Fix-memory-leak-on-uninserted-lv-references.patch \
+           file://0019-disk-cryptodisk-Fix-potential-integer-overflow.patch \
            "
 SRC_URI[md5sum] = "5ce674ca6b2612d8939b9e6abed32934"
 SRC_URI[sha256sum] = "f10c85ae3e204dbaec39ae22fa3c5e99f0665417e91c2cb49b7e5031658ba6ea"