[U-Boot] [PATCH v5] cmd: env: extend "env [set|print] -e" to manage UEFI variables

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 10/15/19 3:42 AM, AKASHI Takahiro wrote:
> With this patch, when setting UEFI variable with "env set -e" command,
> we will be able to
> - specify vendor guid with "-guid guid",
> - specify variable attributes,  BOOTSERVICE_ACCESS, RUNTIME_ACCESS,
>    respectively with "-bs" and "-rt",
> - append a value instead of overwriting with "-a",
> - use memory as variable's value instead of explicit values given
>    at the command line with "-i address,size"
>
> If guid is not explicitly given, default value will be used.
>
> When "-at" is given, a variable should be authenticated with
> appropriate signature database before setting or modifying its value.
> (Authentication is not supported yet though.)
>
> Meanwhile, "env print -e," will be modified so that it will dump
> a variable's value only if '-v' (verbose) is specified.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

-rt and -guid make sense to me.

I cannot see a benefit in -v. Why should I not want to see the values of
the variables?

=> help printenv
printenv -e [-guid guid|-all][-v] [name ...]
     - print UEFI variable 'name' or all the variables
       "-v": verbose for signature database

What has -v to do with a signature base in the case of UEFI variables?

-at does not work. So I would not want to introduce it now.

=> setenv -e -guid 00000000-0000-0000-0000-000000000000 a b
## "-bs" is required

-bs - Why should I want to type it if the flag is always needed? Please,
do away with it.

-a - I have no clue why it it needed. Do you have a substantial use case?

=> setenv -e -guid 00000000-0000-0000-0000-00000000 a b
## Guid not specified or in bad format

"## Guid not in XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX format" would be
more helpful.

Best regards

Heinrich


> ---
> Changes in v5 (Oct 15, 2019)
> * improve a message in case of wrong guid format
> * improve a message in case that BOOTSERVICE_ACCESS is required
>
> Changes in v4 (Oct 7, 2019)
> * print usage message if "-guid guid" has a wrong format
> * add "-guid guid"  and "-all" option to "env print -e" command
>    to specify a specific guid (or any guids)
>
> Changes in v3 (Oct 4, 2019)
> * add verbose messages when SetVariable() fails
> * add "-v" option
>
> Changes in v2 (Sept 6, 2019)
> * remove "-at" option
>
> ---
>   cmd/nvedit.c     |  19 +++-
>   cmd/nvedit_efi.c | 283 ++++++++++++++++++++++++++++++++++++++++-------
>   2 files changed, 258 insertions(+), 44 deletions(-)
>
> diff --git a/cmd/nvedit.c b/cmd/nvedit.c
> index 1cb0bc1460b9..cbe6205733de 100644
> --- a/cmd/nvedit.c
> +++ b/cmd/nvedit.c
> @@ -1387,7 +1387,7 @@ static char env_help_text[] =
>   #endif
>   	"env print [-a | name ...] - print environment\n"
>   #if defined(CONFIG_CMD_NVEDIT_EFI)
> -	"env print -e [name ...] - print UEFI environment\n"
> +	"env print -e [-guid guid|-all][-v] [name ...] - print UEFI environment\n"
>   #endif
>   #if defined(CONFIG_CMD_RUN)
>   	"env run var [...] - run commands in an environment variable\n"
> @@ -1399,7 +1399,8 @@ static char env_help_text[] =
>   #endif
>   #endif
>   #if defined(CONFIG_CMD_NVEDIT_EFI)
> -	"env set -e name [arg ...] - set UEFI variable; unset if 'arg' not specified\n"
> +	"env set -e [-nv][-bs][-rt][-a][-i addr,size][-v] name [arg ...]\n"
> +	"    - set UEFI variable; unset if '-i' or 'arg' not specified\n"
>   #endif
>   	"env set [-f] name [arg ...]\n";
>   #endif
> @@ -1428,8 +1429,9 @@ U_BOOT_CMD_COMPLETE(
>   	"print environment variables",
>   	"[-a]\n    - print [all] values of all environment variables\n"
>   #if defined(CONFIG_CMD_NVEDIT_EFI)
> -	"printenv -e [name ...]\n"
> +	"printenv -e [-guid guid|-all][-v] [name ...]\n"
>   	"    - print UEFI variable 'name' or all the variables\n"
> +	"      \"-v\": verbose for signature database\n"
>   #endif
>   	"printenv name ...\n"
>   	"    - print value of environment variable 'name'",
> @@ -1459,9 +1461,16 @@ U_BOOT_CMD_COMPLETE(
>   	setenv, CONFIG_SYS_MAXARGS, 0,	do_env_set,
>   	"set environment variables",
>   #if defined(CONFIG_CMD_NVEDIT_EFI)
> -	"-e [-nv] name [value ...]\n"
> +	"-e [-guid guid][-nv][-bs][-rt][-a][-v]\n"
> +	"        [-i addr,size name], or [name [value ...]]\n"
>   	"    - set UEFI variable 'name' to 'value' ...'\n"
> -	"      'nv' option makes the variable non-volatile\n"
> +	"      \"-guid\": set vendor guid\n"
> +	"      \"-nv\": set non-volatile attribute\n"
> +	"      \"-bs\": set boot-service attribute\n"
> +	"      \"-rt\": set runtime attribute\n"
> +	"      \"-a\": append-write\n"
> +	"      \"-i addr,size\": use <addr,size> as variable's value\n"
> +	"      \"-v\": verbose print\n"
>   	"    - delete UEFI variable 'name' if 'value' not specified\n"
>   #endif
>   	"setenv [-f] name value ...\n"
> diff --git a/cmd/nvedit_efi.c b/cmd/nvedit_efi.c
> index ed6d09a53046..44ae400a1d45 100644
> --- a/cmd/nvedit_efi.c
> +++ b/cmd/nvedit_efi.c
> @@ -13,6 +13,7 @@
>   #include <exports.h>
>   #include <hexdump.h>
>   #include <malloc.h>
> +#include <mapmem.h>
>   #include <linux/kernel.h>
>
>   /*
> @@ -34,15 +35,49 @@ static const struct {
>   	{EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS, "AT"},
>   };
>
> +static const struct {
> +	efi_guid_t guid;
> +	char *text;
> +} efi_guid_text[] = {
> +	/* signature database */
> +	{EFI_GLOBAL_VARIABLE_GUID, "EFI_GLOBAL_VARIABLE_GUID"},
> +};
> +
> +/* "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" */
> +static char unknown_guid[37];
> +
> +/**
> + * efi_guid_to_str() - convert guid to readable name
> + *
> + * @guid:	GUID
> + * Return:	string for GUID
> + *
> + * convert guid to readable name
> + */
> +static const char *efi_guid_to_str(const efi_guid_t *guid)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(efi_guid_text); i++)
> +		if (!guidcmp(guid, &efi_guid_text[i].guid))
> +			return efi_guid_text[i].text;
> +
> +	uuid_bin_to_str((unsigned char *)guid->b, unknown_guid,
> +			UUID_STR_FORMAT_GUID);
> +
> +	return unknown_guid;
> +}
> +
>   /**
>    * efi_dump_single_var() - show information about a UEFI variable
>    *
>    * @name:	Name of the variable
>    * @guid:	Vendor GUID
> + * @verbose:	if true, dump data
>    *
>    * Show information encoded in one UEFI variable
>    */
> -static void efi_dump_single_var(u16 *name, efi_guid_t *guid)
> +static void efi_dump_single_var(u16 *name, const efi_guid_t *guid, bool verbose)
>   {
>   	u32 attributes;
>   	u8 *data;
> @@ -68,7 +103,7 @@ static void efi_dump_single_var(u16 *name, efi_guid_t *guid)
>   	if (ret != EFI_SUCCESS)
>   		goto out;
>
> -	printf("%ls:", name);
> +	printf("%ls:\n    %s:", name, efi_guid_to_str(guid));
>   	for (count = 0, i = 0; i < ARRAY_SIZE(efi_var_attrs); i++)
>   		if (attributes & efi_var_attrs[i].mask) {
>   			if (count)
> @@ -79,7 +114,9 @@ static void efi_dump_single_var(u16 *name, efi_guid_t *guid)
>   			puts(efi_var_attrs[i].text);
>   		}
>   	printf(", DataSize = 0x%zx\n", size);
> -	print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1, data, size, true);
> +	if (verbose)
> +		print_hex_dump("    ", DUMP_PREFIX_OFFSET, 16, 1,
> +			       data, size, true);
>
>   out:
>   	free(data);
> @@ -90,11 +127,13 @@ out:
>    *
>    * @argc:	Number of arguments (variables)
>    * @argv:	Argument (variable name) array
> + * @verbose:	if true, dump data
>    * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
>    *
>    * Show information encoded in named UEFI variables
>    */
> -static int efi_dump_vars(int argc,  char * const argv[])
> +static int efi_dump_vars(int argc,  char * const argv[],
> +			 const efi_guid_t *guid, bool verbose)
>   {
>   	u16 *var_name16, *p;
>   	efi_uintn_t buf_size, size;
> @@ -119,8 +158,7 @@ static int efi_dump_vars(int argc,  char * const argv[])
>   		p = var_name16;
>   		utf8_utf16_strcpy(&p, argv[0]);
>
> -		efi_dump_single_var(var_name16,
> -				    (efi_guid_t *)&efi_global_variable_guid);
> +		efi_dump_single_var(var_name16, guid, verbose);
>   	}
>
>   	free(var_name16);
> @@ -128,20 +166,56 @@ static int efi_dump_vars(int argc,  char * const argv[])
>   	return CMD_RET_SUCCESS;
>   }
>
> +static bool match_name(int argc, char * const argv[], u16 *var_name16)
> +{
> +	char *buf, *p;
> +	size_t buflen;
> +	int i;
> +	bool result = false;
> +
> +	buflen = utf16_utf8_strlen(var_name16) + 1;
> +	buf = calloc(1, buflen);
> +	if (!buf)
> +		return result;
> +
> +	p = buf;
> +	utf16_utf8_strcpy(&p, var_name16);
> +
> +	for (i = 0; i < argc; argc--, argv++) {
> +		if (!strcmp(buf, argv[i])) {
> +			result = true;
> +			goto out;
> +		}
> +	}
> +
> +out:
> +	free(buf);
> +
> +	return result;
> +}
> +
>   /**
> - * efi_dump_vars() - show information about all the UEFI variables
> + * efi_dump_var_all() - show information about all the UEFI variables
>    *
> + * @argc:	Number of arguments (variables)
> + * @argv:	Argument (variable name) array
> + * @verbose:	if true, dump data
>    * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
>    *
>    * Show information encoded in all the UEFI variables
>    */
> -static int efi_dump_var_all(void)
> +static int efi_dump_var_all(int argc,  char * const argv[],
> +			    const efi_guid_t *guid_p, bool verbose)
>   {
>   	u16 *var_name16, *p;
>   	efi_uintn_t buf_size, size;
>   	efi_guid_t guid;
>   	efi_status_t ret;
>
> +	if (argc && guid_p)
> +		/* simplified case */
> +		return efi_dump_vars(argc, argv, guid_p, verbose);
> +
>   	buf_size = 128;
>   	var_name16 = malloc(buf_size);
>   	if (!var_name16)
> @@ -171,7 +245,9 @@ static int efi_dump_var_all(void)
>   			return CMD_RET_FAILURE;
>   		}
>
> -		efi_dump_single_var(var_name16, &guid);
> +		if ((!guid_p || !guidcmp(guid_p, &guid)) &&
> +		    (!argc || match_name(argc, argv, var_name16)))
> +			efi_dump_single_var(var_name16, &guid, verbose);
>   	}
>
>   	free(var_name16);
> @@ -189,12 +265,15 @@ static int efi_dump_var_all(void)
>    * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
>    *
>    * This function is for "env print -e" or "printenv -e" command:
> - *   => env print -e [var [...]]
> + *   => env print -e [-v] [-guid <guid> | -all] [var [...]]
>    * If one or more variable names are specified, show information
>    * named UEFI variables, otherwise show all the UEFI variables.
>    */
>   int do_env_print_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>   {
> +	efi_guid_t guid;
> +	const efi_guid_t *guid_p;
> +	bool default_guid, guid_any, verbose;
>   	efi_status_t ret;
>
>   	/* Initialize EFI drivers */
> @@ -205,12 +284,47 @@ int do_env_print_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>   		return CMD_RET_FAILURE;
>   	}
>
> -	if (argc > 1)
> -		/* show specified UEFI variables */
> -		return efi_dump_vars(--argc, ++argv);
> +	default_guid = true;
> +	guid_any = false;
> +	verbose = false;
> +	for (argc--, argv++; argc > 0 && argv[0][0] == '-'; argc--, argv++) {
> +		if (!strcmp(argv[0], "-guid")) {
> +			if (argc == 1)
> +				return CMD_RET_USAGE;
> +
> +			/* -a already specified */
> +			if (!default_guid & guid_any)
> +				return CMD_RET_USAGE;
> +
> +			argc--;
> +			argv++;
> +			if (uuid_str_to_bin(argv[0], guid.b,
> +					    UUID_STR_FORMAT_GUID))
> +				return CMD_RET_USAGE;
> +			default_guid = false;
> +		} else if (!strcmp(argv[0], "-all")) {
> +			/* -guid already specified */
> +			if (!default_guid && !guid_any)
> +				return CMD_RET_USAGE;
> +
> +			guid_any = true;
> +			default_guid = false;
> +		} else if (!strcmp(argv[0], "-v")) {
> +			verbose = true;
> +		} else {
> +			return CMD_RET_USAGE;
> +		}
> +	}
> +
> +	if (guid_any)
> +		guid_p = NULL;
> +	else if (default_guid)
> +		guid_p = &efi_global_variable_guid;
> +	else
> +		guid_p = (const efi_guid_t *)guid.b;
>
>   	/* enumerate and show all UEFI variables */
> -	return efi_dump_var_all();
> +	return efi_dump_var_all(argc, argv, guid_p, verbose);
>   }
>
>   /**
> @@ -339,18 +453,22 @@ out:
>    * Return:	CMD_RET_SUCCESS on success, or CMD_RET_RET_FAILURE
>    *
>    * This function is for "env set -e" or "setenv -e" command:
> - *   => env set -e var [value ...]]
> + *   => env set -e [-guid guid][-nv][-bs][-rt][-a][-v]
> + *		   [-i address,size] var, or
> + *                 var [value ...]
>    * Encode values specified and set given UEFI variable.
>    * If no value is specified, delete the variable.
>    */
>   int do_env_set_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>   {
> -	char *var_name, *value = NULL;
> -	efi_uintn_t size = 0;
> -	u16 *var_name16 = NULL, *p;
> -	size_t len;
> +	char *var_name, *value, *ep;
> +	ulong addr;
> +	efi_uintn_t size;
>   	efi_guid_t guid;
>   	u32 attributes;
> +	bool default_guid, verbose, value_on_memory;
> +	u16 *var_name16 = NULL, *p;
> +	size_t len;
>   	efi_status_t ret;
>
>   	if (argc == 1)
> @@ -364,32 +482,94 @@ int do_env_set_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>   		return CMD_RET_FAILURE;
>   	}
>
> -	attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
> -		     EFI_VARIABLE_RUNTIME_ACCESS;
> -	if (!strcmp(argv[1], "-nv")) {
> -		attributes |= EFI_VARIABLE_NON_VOLATILE;
> -		argc--;
> -		argv++;
> -		if (argc == 1)
> -			return CMD_RET_SUCCESS;
> +	/*
> +	 * attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS |
> +	 *	     EFI_VARIABLE_RUNTIME_ACCESS;
> +	 */
> +	value = NULL;
> +	size = 0;
> +	attributes = 0;
> +	guid = efi_global_variable_guid;
> +	default_guid = true;
> +	verbose = false;
> +	value_on_memory = false;
> +	for (argc--, argv++; argc > 0 && argv[0][0] == '-'; argc--, argv++) {
> +		if (!strcmp(argv[0], "-guid")) {
> +			if (argc == 1)
> +				return CMD_RET_USAGE;
> +
> +			argc--;
> +			argv++;
> +			if (uuid_str_to_bin(argv[0], guid.b,
> +					    UUID_STR_FORMAT_GUID)) {
> +				printf("## Guid not specified or in bad format\n");
> +				return CMD_RET_FAILURE;
> +			}
> +			default_guid = false;
> +		} else if (!strcmp(argv[0], "-bs")) {
> +			attributes |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
> +		} else if (!strcmp(argv[0], "-rt")) {
> +			attributes |= EFI_VARIABLE_RUNTIME_ACCESS;
> +		} else if (!strcmp(argv[0], "-nv")) {
> +			attributes |= EFI_VARIABLE_NON_VOLATILE;
> +		} else if (!strcmp(argv[0], "-a")) {
> +			attributes |= EFI_VARIABLE_APPEND_WRITE;
> +		} else if (!strcmp(argv[0], "-i")) {
> +			/* data comes from memory */
> +			if (argc == 1)
> +				return CMD_RET_USAGE;
> +
> +			argc--;
> +			argv++;
> +			addr = simple_strtoul(argv[0], &ep, 16);
> +			if (*ep != ',')
> +				return CMD_RET_USAGE;
> +
> +			size = simple_strtoul(++ep, NULL, 16);
> +			if (!size)
> +				return CMD_RET_FAILURE;
> +			value_on_memory = true;
> +		} else if (!strcmp(argv[0], "-v")) {
> +			verbose = true;
> +		} else {
> +			return CMD_RET_USAGE;
> +		}
>   	}
> +	if (!argc)
> +		return CMD_RET_USAGE;
>
> -	var_name = argv[1];
> -	if (argc == 2) {
> -		/* delete */
> -		value = NULL;
> -		size = 0;
> -	} else { /* set */
> -		argc -= 2;
> -		argv += 2;
> +	var_name = argv[0];
> +	if (default_guid)
> +		guid = efi_global_variable_guid;
>
> -		for ( ; argc > 0; argc--, argv++)
> +	if (verbose) {
> +		printf("GUID: %s\n", efi_guid_to_str((const efi_guid_t *)
> +						     &guid));
> +		printf("Attributes: 0x%x\n", attributes);
> +	}
> +
> +	/* for value */
> +	if (value_on_memory)
> +		value = map_sysmem(addr, 0);
> +	else if (argc > 1)
> +		for (argc--, argv++; argc > 0; argc--, argv++)
>   			if (append_value(&value, &size, argv[0]) < 0) {
>   				printf("## Failed to process an argument, %s\n",
>   				       argv[0]);
>   				ret = CMD_RET_FAILURE;
>   				goto out;
>   			}
> +
> +	if (size && !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)) {
> +		printf("## \"-bs\" is required\n");
> +		ret = CMD_RET_FAILURE;
> +		goto out;
> +	}
> +
> +	if (size && verbose) {
> +		printf("Value:\n");
> +		print_hex_dump("    ", DUMP_PREFIX_OFFSET,
> +			       16, 1, value, size, true);
>   	}
>
>   	len = utf8_utf16_strnlen(var_name, strlen(var_name));
> @@ -402,17 +582,42 @@ int do_env_set_efi(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>   	p = var_name16;
>   	utf8_utf16_strncpy(&p, var_name, len + 1);
>
> -	guid = efi_global_variable_guid;
>   	ret = EFI_CALL(efi_set_variable(var_name16, &guid, attributes,
>   					size, value));
> +	unmap_sysmem(value);
>   	if (ret == EFI_SUCCESS) {
>   		ret = CMD_RET_SUCCESS;
>   	} else {
> -		printf("## Failed to set EFI variable\n");
> +		const char *msg;
> +
> +		switch (ret) {
> +		case EFI_NOT_FOUND:
> +			msg = " (not found)";
> +			break;
> +		case EFI_WRITE_PROTECTED:
> +			msg = " (read only)";
> +			break;
> +		case EFI_INVALID_PARAMETER:
> +			msg = " (invalid parameter)";
> +			break;
> +		case EFI_SECURITY_VIOLATION:
> +			msg = " (validation failed)";
> +			break;
> +		case EFI_OUT_OF_RESOURCES:
> +			msg = " (out of memory)";
> +			break;
> +		default:
> +			msg = "";
> +			break;
> +		}
> +		printf("## Failed to set EFI variable%s\n", msg);
>   		ret = CMD_RET_FAILURE;
>   	}
>   out:
> -	free(value);
> +	if (value_on_memory)
> +		unmap_sysmem(value);
> +	else
> +		free(value);
>   	free(var_name16);
>
>   	return ret;
>