1 files changed, 82 insertions, 0 deletions

diff --git a/meta/recipes-bsp/grub/files/CVE-2021-3697.patch b/meta/recipes-bsp/grub/files/CVE-2021-3697.patch
new file mode 100644
index 0000000000..be15e7d1f2
--- /dev/null
+++ b/meta/recipes-bsp/grub/files/CVE-2021-3697.patch
@@ -0,0 +1,82 @@
+From 4de9de9d14f4ac27229e45514627534e32cc4406 Mon Sep 17 00:00:00 2001
+From: Hitendra Prajapati <hprajapati@mvista.com>
+Date: Tue, 19 Jul 2022 11:13:02 +0530
+Subject: [PATCH] CVE-2021-3697
+
+Upstream-Status: Backport [https://git.savannah.gnu.org/gitweb/?p=grub.git;a=commit;h=22a3f97d39f6a10b08ad7fd1cc47c4dcd10413f6]
+CVE: CVE-2021-3697
+Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
+
+video/readers/jpeg: Block int underflow -> wild pointer write
+
+Certain 1 px wide images caused a wild pointer write in
+grub_jpeg_ycrcb_to_rgb(). This was caused because in grub_jpeg_decode_data(),
+we have the following loop:
+
+for (; data->r1 < nr1 && (!data->dri || rst);
+     data->r1++, data->bitmap_ptr += (vb * data->image_width - hb * nc1) * 3)
+
+We did not check if vb * width >= hb * nc1.
+
+On a 64-bit platform, if that turns out to be negative, it will underflow,
+be interpreted as unsigned 64-bit, then be added to the 64-bit pointer, so
+we see data->bitmap_ptr jump, e.g.:
+
+0x6180_0000_0480 to
+0x6181_0000_0498
+     ^
+     ~--- carry has occurred and this pointer is now far away from
+          any object.
+
+On a 32-bit platform, it will decrement the pointer, creating a pointer
+that won't crash but will overwrite random data.
+
+Catch the underflow and error out.
+
+Fixes: CVE-2021-3697
+
+Signed-off-by: Daniel Axtens <dja@axtens.net>
+Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
+---
+ grub-core/video/readers/jpeg.c | 10 +++++++++-
+ 1 file changed, 9 insertions(+), 1 deletion(-)
+
+diff --git a/grub-core/video/readers/jpeg.c b/grub-core/video/readers/jpeg.c
+index 31359a4..545a60b 100644
+--- a/grub-core/video/readers/jpeg.c
++++ b/grub-core/video/readers/jpeg.c
+@@ -23,6 +23,7 @@
+ #include <grub/mm.h>
+ #include <grub/misc.h>
+ #include <grub/bufio.h>
++#include <grub/safemath.h>
+ 
+ GRUB_MOD_LICENSE ("GPLv3+");
+ 
+@@ -617,6 +618,7 @@ static grub_err_t
+ grub_jpeg_decode_data (struct grub_jpeg_data *data)
+ {
+   unsigned c1, vb, hb, nr1, nc1;
++  unsigned stride_a, stride_b, stride;
+   int rst = data->dri;
+ 
+   vb = 8 << data->log_vs;
+@@ -624,8 +626,14 @@ grub_jpeg_decode_data (struct grub_jpeg_data *data)
+   nr1 = (data->image_height + vb - 1) >> (3 + data->log_vs);
+   nc1 = (data->image_width + hb - 1)  >> (3 + data->log_hs);
+ 
++  if (grub_mul(vb, data->image_width, &stride_a) ||
++      grub_mul(hb, nc1, &stride_b) ||
++      grub_sub(stride_a, stride_b, &stride))
++    return grub_error (GRUB_ERR_BAD_FILE_TYPE,
++                      "jpeg: cannot decode image with these dimensions");
++
+   for (; data->r1 < nr1 && (!data->dri || rst);
+-       data->r1++, data->bitmap_ptr += (vb * data->image_width - hb * nc1) * 3)
++       data->r1++, data->bitmap_ptr += stride * 3)
+     for (c1 = 0;  c1 < nc1 && (!data->dri || rst);
+        c1++, rst--, data->bitmap_ptr += hb * 3)
+       {
+-- 
+2.25.1
+