[U-Boot] [PATCH] efi_selftest: check for buffer overflow in efi_get_variable

[U-Boot] [PATCH] efi_selftest: check for buffer overflow in efi_get_variable

[Ivan Gorinov]

Check if GetVariable writes past the end of the output data buffer.

Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com>
---
 lib/efi_selftest/efi_selftest_variables.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/efi_selftest/efi_selftest_variables.c b/lib/efi_selftest/efi_selftest_variables.c
index f5e8eb6..8a02dbc 100644
--- a/lib/efi_selftest/efi_selftest_variables.c
+++ b/lib/efi_selftest/efi_selftest_variables.c
@@ -72,6 +72,22 @@ static int execute(void)
 		efi_st_error("SetVariable failed\n");
 		return EFI_ST_FAILURE;
 	}
+	data[3] = 0xff;
+	len = 3;
+	ret = runtime->get_variable(L"efi_st_var0", &guid_vendor0,
+				    &attr, &len, data);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("GetVariable failed\n");
+		return EFI_ST_FAILURE;
+	}
+	if (efi_st_memcmp(data, v + 4, 3)) {
+		efi_st_error("GetVariable returned wrong value\n");
+		return EFI_ST_FAILURE;
+	}
+	if (data[3] != 0xff) {
+		efi_st_error("GetVariable wrote past the end of the buffer\n");
+		return EFI_ST_FAILURE;
+	}
 	/* Set variable 1 */
 	ret = runtime->set_variable(L"efi_st_var1", &guid_vendor1,
 				    EFI_VARIABLE_BOOTSERVICE_ACCESS,
-- 
2.7.4

[U-Boot] [PATCH] efi_selftest: check for buffer overflow in efi_get_variable

[Heinrich Schuchardt]

On 05/25/2018 02:09 AM, Ivan Gorinov wrote:
> Check if GetVariable writes past the end of the output data buffer.
> 
> Signed-off-by: Ivan Gorinov <ivan.gorinov@intel.com>

The patch produces build warnings:

lib/efi_selftest/efi_selftest_variables.c: In function ‘execute’:
lib/efi_selftest/efi_selftest_variables.c:75:10: warning: assignment
makes pointer from integer without a cast [-Wint-conversion]
  data[3] = 0xff;
          ^
lib/efi_selftest/efi_selftest_variables.c:87:14: warning: comparison
between pointer and integer
  if (data[3] != 0xff) {

This is due to an inappropriate definition in my prior patch. Could you,
please, add this change:

-u8 *data[EFI_ST_MAX_DATA_SIZE];
+u8 data[EFI_ST_MAX_DATA_SIZE];

Otherwise your patch is fine.

Best regards

Heinrich

> ---
>  lib/efi_selftest/efi_selftest_variables.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/lib/efi_selftest/efi_selftest_variables.c b/lib/efi_selftest/efi_selftest_variables.c
> index f5e8eb6..8a02dbc 100644
> --- a/lib/efi_selftest/efi_selftest_variables.c
> +++ b/lib/efi_selftest/efi_selftest_variables.c
> @@ -72,6 +72,22 @@ static int execute(void)
>  		efi_st_error("SetVariable failed\n");
>  		return EFI_ST_FAILURE;
>  	}
> +	data[3] = 0xff;
> +	len = 3;
> +	ret = runtime->get_variable(L"efi_st_var0", &guid_vendor0,
> +				    &attr, &len, data);
> +	if (ret != EFI_SUCCESS) {
> +		efi_st_error("GetVariable failed\n");
> +		return EFI_ST_FAILURE;
> +	}
> +	if (efi_st_memcmp(data, v + 4, 3)) {
> +		efi_st_error("GetVariable returned wrong value\n");
> +		return EFI_ST_FAILURE;
> +	}
> +	if (data[3] != 0xff) {
> +		efi_st_error("GetVariable wrote past the end of the buffer\n");
> +		return EFI_ST_FAILURE;
> +	}
>  	/* Set variable 1 */
>  	ret = runtime->set_variable(L"efi_st_var1", &guid_vendor1,
>  				    EFI_VARIABLE_BOOTSERVICE_ACCESS,
>