[tip: x86/mm] x86/tdx: Replace deprecated strncpy() with strtomem_pad()

[tip-bot2 for Justin Stitt]

The following commit has been merged into the x86/mm branch of tip:

Commit-ID:     c9babd5d95abf3fae6e798605ce5cac98e08daf9
Gitweb:        https://git.kernel.org/tip/c9babd5d95abf3fae6e798605ce5cac98e08daf9
Author:        Justin Stitt <justinstitt@xxxxxxxxxx>
AuthorDate:    Tue, 03 Oct 2023 21:54:59 
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 04 Oct 2023 09:34:07 +02:00

x86/tdx: Replace deprecated strncpy() with strtomem_pad()

strncpy() works perfectly here in all cases, however, it is deprecated and
as such we should prefer more robust and less ambiguous string APIs:

    https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings

Let's use strtomem_pad() as this matches the functionality of strncpy()
and is _not_ deprecated.

Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://github.com/KSPP/linux/issues/90
Link: https://lore.kernel.org/r/20231003-strncpy-arch-x86-coco-tdx-tdx-c-v2-1-0bd21174a217@xxxxxxxxxx
---
 arch/x86/coco/tdx/tdx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index 1d6b863..2e1be59 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -119,7 +119,7 @@ static void __noreturn tdx_panic(const char *msg)
 	} message;
 
 	/* VMM assumes '\0' in byte 65, if the message took all 64 bytes */
-	strncpy(message.str, msg, 64);
+	strtomem_pad(message.str, msg, '\0');
 
 	args.r8  = message.r8;
 	args.r9  = message.r9;