From c4039b29fe9637e1135912813f830994af4c867f Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 23 Apr 2021 14:48:31 +0300
Subject: [PATCH] efi/libstub: prevent read overflow in find_file_option()
Git-commit: c4039b29fe9637e1135912813f830994af4c867f
Patch-mainline: v5.13-rc5
References: git-fixes
If the buffer has slashes up to the end then this will read past the end
of the array. I don't anticipate that this is an issue for many people
in real life, but it's the right thing to do and it makes static
checkers happy.
Fixes: 7a88a6227dc7 ("efi/libstub: Fix path separator regression")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/firmware/efi/libstub/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/firmware/efi/libstub/file.c b/drivers/firmware/efi/libstub/file.c
index 4e81c6077188..dd95f330fe6e 100644
--- a/drivers/firmware/efi/libstub/file.c
+++ b/drivers/firmware/efi/libstub/file.c
@@ -103,7 +103,7 @@ static int find_file_option(const efi_char16_t *cmdline, int cmdline_len,
return 0;
/* Skip any leading slashes */
- while (cmdline[i] == L'/' || cmdline[i] == L'\\')
+ while (i < cmdline_len && (cmdline[i] == L'/' || cmdline[i] == L'\\'))
i++;
while (--result_len > 0 && i < cmdline_len) {
--
2.26.2