From: AKASHI Takahiro <takahiro.akashi@linaro.org>
Date: Fri, 22 Jan 2021 01:42:48 +0000 (+0900)
Subject: cmd: efidebug: always check return code from get_variable()
X-Git-Url: http://git.dujemihanovic.xyz/img/sics.gif?a=commitdiff_plain;h=30f8222bb0016eef29afdd997bd1b3cdc486fdf9;p=u-boot.git

cmd: efidebug: always check return code from get_variable()

CID 316364 says:
> Null pointer dereferences  (FORWARD_NULL)
>	printf("Result total size: 0x%x\n", result->variable_total_size);
at do_efi_capsule_res().

The code is basically safe because a buffer for "result" is allocated
by malloc() and filled up by the second get_variable(), which fails any way
if the allocation has failed.

But the first (and second) get_variable() possibly returns an error other
than EFI_SUCCESS. We always need to check the return code from
get_variable() before accessing the data in "result".

While this change won't suppress CID 316364, the resulting code is much
safer.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---

diff --git a/cmd/efidebug.c b/cmd/efidebug.c
index 9a2d4ddd5e..83bc2196a5 100644
--- a/cmd/efidebug.c
+++ b/cmd/efidebug.c
@@ -189,14 +189,16 @@ static int do_efi_capsule_res(struct cmd_tbl *cmdtp, int flag,
 	ret = EFI_CALL(RT->get_variable(var_name16, &guid, NULL, &size, NULL));
 	if (ret == EFI_BUFFER_TOO_SMALL) {
 		result = malloc(size);
+		if (!result)
+			return CMD_RET_FAILURE;
 		ret = EFI_CALL(RT->get_variable(var_name16, &guid, NULL, &size,
 						result));
-		if (ret != EFI_SUCCESS) {
-			free(result);
-			printf("Failed to get %ls\n", var_name16);
+	}
+	if (ret != EFI_SUCCESS) {
+		free(result);
+		printf("Failed to get %ls\n", var_name16);
 
-			return CMD_RET_FAILURE;
-		}
+		return CMD_RET_FAILURE;
 	}
 
 	printf("Result total size: 0x%x\n", result->variable_total_size);