grub: backport strlcpy function

It is used to fix multiple CVEs.

(From OE-Core rev: c12baf254a37ff4921c2be0e4d3f626a91980d1a)

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/recipes-bsp/grub/files/0001-misc-Implement-grub_strlcpy.patch

@@ -0,0 +1,68 @@
+From ea703528a8581a2ea7e0bad424a70fdf0aec7d8f Mon Sep 17 00:00:00 2001
+From: B Horn <b@horn.uk>
+Date: Sat, 15 Jun 2024 02:33:08 +0100
+Subject: [PATCH 1/2] misc: Implement grub_strlcpy()
+
+grub_strlcpy() acts the same way as strlcpy() does on most *NIX,
+returning the length of src and ensuring dest is always NUL
+terminated except when size is 0.
+
+Signed-off-by: B Horn <b@horn.uk>
+Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
+
+Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=ea703528a8581a2ea7e0bad424a70fdf0aec7d8f]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ include/grub/misc.h | 39 +++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 39 insertions(+)
+
+diff --git a/include/grub/misc.h b/include/grub/misc.h
+index 1578f36c3..14d8f37ac 100644
+--- a/include/grub/misc.h
++++ b/include/grub/misc.h
+@@ -64,6 +64,45 @@ grub_stpcpy (char *dest, const char *src)
+   return d - 1;
+ }
+ 
++static inline grub_size_t
++grub_strlcpy (char *dest, const char *src, grub_size_t size)
++{
++  char *d = dest;
++  grub_size_t res = 0;
++  /*
++   * We do not subtract one from size here to avoid dealing with underflowing
++   * the value, which is why to_copy is always checked to be greater than one
++   * throughout this function.
++   */
++  grub_size_t to_copy = size;
++
++  /* Copy size - 1 bytes to dest. */
++  if (to_copy > 1)
++    while ((*d++ = *src++) != '\0' && ++res && --to_copy > 1)
++      ;
++
++  /*
++   * NUL terminate if size != 0. The previous step may have copied a NUL byte
++   * if it reached the end of the string, but we know dest[size - 1] must always
++   * be a NUL byte.
++   */
++  if (size != 0)
++    dest[size - 1] = '\0';
++
++  /* If there is still space in dest, but are here, we reached the end of src. */
++  if (to_copy > 1)
++    return res;
++
++  /*
++   * If we haven't reached the end of the string, iterate through to determine
++   * the strings total length.
++   */
++  while (*src++ != '\0' && ++res)
++   ;
++
++  return res;
++}
++
+ /* XXX: If grub_memmove is too slow, we must implement grub_memcpy.  */
+ static inline void *
+ grub_memcpy (void *dest, const void *src, grub_size_t n)

meta/recipes-bsp/grub/grub2.inc

@@ -19,6 +19,7 @@ SRC_URI = "${GNU_MIRROR}/grub/grub-${PV}.tar.gz \
            file://grub-module-explicitly-keeps-symbole-.module_license.patch \
            file://0001-grub.d-10_linux.in-add-oe-s-kernel-name.patch \
            file://0001-RISC-V-Restore-the-typcast-to-long.patch \
+           file://0001-misc-Implement-grub_strlcpy.patch \
 "
 
 SRC_URI[sha256sum] = "b30919fa5be280417c17ac561bb1650f60cfb80cc6237fa1e2b6f56154cb9c91"