[xen staging] xen/efi: Rewrite DOS/PE magic checking without memcmp()

[patchbot@xxxxxxx]

commit 4cd66fb56dc6972178f6543217b66bc122fbbd5a
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Apr 16 16:21:34 2024 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Apr 18 20:43:11 2024 +0100

    xen/efi: Rewrite DOS/PE magic checking without memcmp()
    
    Misra Rule 21.16 doesn't like the use of memcmp() against character arrays 
(a
    string literal in this case).  This is a rare piece of logic where we're
    looking for a magic marker that just happens to make sense when expressed as
    ASCII.  Rewrite using plain compares.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/common/efi/pe.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/xen/common/efi/pe.c b/xen/common/efi/pe.c
index a84992df9a..ef8a2543e0 100644
--- a/xen/common/efi/pe.c
+++ b/xen/common/efi/pe.c
@@ -111,7 +111,8 @@ const void *__init pe_find_section(const void *image, const 
UINTN image_size,
     UINTN offset, i;
 
     if ( image_size < sizeof(*dos) ||
-         memcmp(dos->Magic, "MZ", 2) != 0 )
+         dos->Magic[0] != 'M' ||
+         dos->Magic[1] != 'Z' )
         return NULL;
 
     offset = dos->ExeHeader;
@@ -119,7 +120,10 @@ const void *__init pe_find_section(const void *image, 
const UINTN image_size,
 
     offset += sizeof(*pe);
     if ( image_size < offset ||
-         memcmp(pe->Magic, "PE\0\0", 4) != 0 )
+         pe->Magic[0] != 'P' ||
+         pe->Magic[1] != 'E' ||
+         pe->Magic[2] != '\0' ||
+         pe->Magic[3] != '\0' )
         return NULL;
 
     if ( pe->FileHeader.Machine != PE_HEADER_MACHINE )
--
generated by git-patchbot for /home/xen/git/xen.git#staging