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env: Add support for access control to .flags

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Add support for read-only, write-once, and change-default.

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
This commit is contained in:
Joe Hershberger 2012-12-11 22:16:34 -06:00 committed by Tom Rini
parent fffad71bc4
commit 267541f776
7 changed files with 330 additions and 18 deletions
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13
README
View file

@ -3128,7 +3128,8 @@ Configuration Settings:
The format of the list is:
type_attribute = [s|d|x|b|i|m]
attributes = type_attribute
access_atribute = [a|r|o|c]
attributes = type_attribute[access_atribute]
entry = variable_name[:attributes]
list = entry[,list]
@ -3140,6 +3141,12 @@ Configuration Settings:
i - IP address
m - MAC address
The access attributes are:
a - Any (default)
r - Read-only
o - Write-once
c - Change-default
- CONFIG_ENV_FLAGS_LIST_DEFAULT
Define this to a list (string) to define the ".flags"
envirnoment variable in the default or embedded environment.
@ -3151,6 +3158,10 @@ Configuration Settings:
list, simply add an entry for the same variable name to the
".flags" variable.
- CONFIG_ENV_ACCESS_IGNORE_FORCE
If defined, don't allow the -f switch to env set override variable
access flags.
The following definitions that deal with the placement and management
of environment data (variable area); in general, we support the
following configurations:

31
common/cmd_nvedit.c
View file

@ -447,8 +447,11 @@ int do_env_callback(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
static int print_static_flags(const char *var_name, const char *flags)
{
enum env_flags_vartype type = env_flags_parse_vartype(flags);
enum env_flags_varaccess access = env_flags_parse_varaccess(flags);
printf("\t%-20s %-20s\n", var_name, env_flags_get_vartype_name(type));
printf("\t%-20s %-20s %-20s\n", var_name,
env_flags_get_vartype_name(type),
env_flags_get_varaccess_name(access));
return 0;
}
@ -456,13 +459,17 @@ static int print_static_flags(const char *var_name, const char *flags)
static int print_active_flags(ENTRY *entry)
{
enum env_flags_vartype type;
enum env_flags_varaccess access;
if (entry->flags == 0)
return 0;
type = (enum env_flags_vartype)
(entry->flags & ENV_FLAGS_VARTYPE_BIN_MASK);
printf("\t%-20s %-20s\n", entry->key, env_flags_get_vartype_name(type));
access = env_flags_parse_varaccess_from_binflags(entry->flags);
printf("\t%-20s %-20s %-20s\n", entry->key,
env_flags_get_vartype_name(type),
env_flags_get_varaccess_name(access));
return 0;
}
@ -480,17 +487,29 @@ int do_env_flags(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
env_flags_print_vartypes();
puts("\n");
/* Print the available variable access types */
printf("Available variable access flags (position %d):\n",
ENV_FLAGS_VARACCESS_LOC);
puts("\tFlag\tVariable Access Name\n");
puts("\t----\t--------------------\n");
env_flags_print_varaccess();
puts("\n");
/* Print the static flags that may exist */
puts("Static flags:\n");
printf("\t%-20s %-20s\n", "Variable Name", "Variable Type");
printf("\t%-20s %-20s\n", "-------------", "-------------");
printf("\t%-20s %-20s %-20s\n", "Variable Name", "Variable Type",
"Variable Access");
printf("\t%-20s %-20s %-20s\n", "-------------", "-------------",
"---------------");
env_attr_walk(ENV_FLAGS_LIST_STATIC, print_static_flags);
puts("\n");
/* walk through each variable and print the flags if non-default */
puts("Active flags:\n");
printf("\t%-20s %-20s\n", "Variable Name", "Variable Type");
printf("\t%-20s %-20s\n", "-------------", "-------------");
printf("\t%-20s %-20s %-20s\n", "Variable Name", "Variable Type",
"Variable Access");
printf("\t%-20s %-20s %-20s\n", "-------------", "-------------",
"---------------");
hwalk_r(&env_htab, print_active_flags);
return 0;
}

18
common/env_common.c
View file

@ -95,6 +95,24 @@ int getenv_yesno(const char *var)
1 : 0;
}
/*
* Look up the variable from the default environment
*/
char *getenv_default(const char *name)
{
char *ret_val;
unsigned long really_valid = gd->env_valid;
unsigned long real_gd_flags = gd->flags;
/* Pretend that the image is bad. */
gd->flags &= ~GD_FLG_ENV_READY;
gd->env_valid = 0;
ret_val = getenv(name);
gd->env_valid = really_valid;
gd->flags = real_gd_flags;
return ret_val;
}
void set_default_env(const char *s)
{
int flags = 0;

159
common/env_flags.c
View file

@ -43,6 +43,17 @@
#endif
static const char env_flags_vartype_rep[] = "sdxb" ENV_FLAGS_NET_VARTYPE_REPS;
static const char env_flags_varaccess_rep[] = "aroc";
static const int env_flags_varaccess_mask[] = {
0,
ENV_FLAGS_VARACCESS_PREVENT_DELETE |
ENV_FLAGS_VARACCESS_PREVENT_CREATE |
ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
ENV_FLAGS_VARACCESS_PREVENT_DELETE |
ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
ENV_FLAGS_VARACCESS_PREVENT_DELETE |
ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR};
#ifdef CONFIG_CMD_ENV_FLAGS
static const char * const env_flags_vartype_names[] = {
"string",
@ -54,6 +65,12 @@ static const char * const env_flags_vartype_names[] = {
"MAC address",
#endif
};
static const char * const env_flags_varaccess_names[] = {
"any",
"read-only",
"write-once",
"change-default",
};
/*
* Print the whole list of available type flags.
@ -69,6 +86,20 @@ void env_flags_print_vartypes(void)
}
}
/*
* Print the whole list of available access flags.
*/
void env_flags_print_varaccess(void)
{
enum env_flags_varaccess curaccess = (enum env_flags_varaccess)0;
while (curaccess != env_flags_varaccess_end) {
printf("\t%c -\t%s\n", env_flags_varaccess_rep[curaccess],
env_flags_varaccess_names[curaccess]);
curaccess++;
}
}
/*
* Return the name of the type.
*/
@ -76,6 +107,14 @@ const char *env_flags_get_vartype_name(enum env_flags_vartype type)
{
return env_flags_vartype_names[type];
}
/*
* Return the name of the access.
*/
const char *env_flags_get_varaccess_name(enum env_flags_varaccess access)
{
return env_flags_varaccess_names[access];
}
#endif /* CONFIG_CMD_ENV_FLAGS */
/*
@ -100,6 +139,46 @@ enum env_flags_vartype env_flags_parse_vartype(const char *flags)
return env_flags_vartype_string;
}
/*
* Parse the flags string from a .flags attribute list into the varaccess enum.
*/
enum env_flags_varaccess env_flags_parse_varaccess(const char *flags)
{
char *access;
if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
return env_flags_varaccess_any;
access = strchr(env_flags_varaccess_rep,
flags[ENV_FLAGS_VARACCESS_LOC]);
if (access != NULL)
return (enum env_flags_varaccess)
(access - &env_flags_varaccess_rep[0]);
printf("## Warning: Unknown environment variable access method '%c'\n",
flags[ENV_FLAGS_VARACCESS_LOC]);
return env_flags_varaccess_any;
}
/*
* Parse the binary flags from a hash table entry into the varaccess enum.
*/
enum env_flags_varaccess env_flags_parse_varaccess_from_binflags(int binflags)
{
int i;
for (i = 0; i < sizeof(env_flags_varaccess_mask); i++)
if (env_flags_varaccess_mask[i] ==
(binflags & ENV_FLAGS_VARACCESS_BIN_MASK))
return (enum env_flags_varaccess)i;
printf("Warning: Non-standard access flags. (0x%x)\n",
binflags & ENV_FLAGS_VARACCESS_BIN_MASK);
return env_flags_varaccess_any;
}
static inline int is_hex_prefix(const char *value)
{
return value[0] == '0' && (value[1] == 'x' || value[1] == 'X');
@ -241,6 +320,23 @@ enum env_flags_vartype env_flags_get_type(const char *name)
return env_flags_parse_vartype(flags);
}
/*
* Look up the access of a variable directly from the .flags var.
*/
enum env_flags_varaccess env_flags_get_varaccess(const char *name)
{
const char *flags_list = getenv(ENV_FLAGS_VAR);
char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];
if (env_flags_lookup(flags_list, name, flags))
return env_flags_varaccess_any;
if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
return env_flags_varaccess_any;
return env_flags_parse_varaccess(flags);
}
/*
* Validate that the proposed new value for "name" is valid according to the
* defined flags for that variable, if any.
@ -261,6 +357,21 @@ int env_flags_validate_type(const char *name, const char *value)
return 0;
}
/*
* Validate that the proposed access to variable "name" is valid according to
* the defined flags for that variable, if any.
*/
int env_flags_validate_varaccess(const char *name, int check_mask)
{
enum env_flags_varaccess access;
int access_mask;
access = env_flags_get_varaccess(name);
access_mask = env_flags_varaccess_mask[access];
return (check_mask & access_mask) != 0;
}
/*
* Validate the parameters to "env set" directly
*/
@ -292,7 +403,12 @@ int env_flags_validate_env_set_params(int argc, char * const argv[])
*/
static int env_parse_flags_to_bin(const char *flags)
{
return env_flags_parse_vartype(flags) & ENV_FLAGS_VARTYPE_BIN_MASK;
int binflags;
binflags = env_flags_parse_vartype(flags) & ENV_FLAGS_VARTYPE_BIN_MASK;
binflags |= env_flags_varaccess_mask[env_flags_parse_varaccess(flags)];
return binflags;
}
/*
@ -377,13 +493,10 @@ int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
int flag)
{
const char *name;
#if !defined(CONFIG_ENV_OVERWRITE) && defined(CONFIG_OVERWRITE_ETHADDR_ONCE) \
&& defined(CONFIG_ETHADDR)
const char *oldval = NULL;
if (op != env_op_create)
oldval = item->data;
#endif
name = item->key;
@ -422,6 +535,44 @@ int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
}
}
/* check for access permission */
#ifndef CONFIG_ENV_ACCESS_IGNORE_FORCE
if (flag & H_FORCE)
return 0;
#endif
switch (op) {
case env_op_delete:
if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_DELETE) {
printf("## Error: Can't delete \"%s\"\n", name);
return 1;
}
break;
case env_op_overwrite:
if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_OVERWR) {
printf("## Error: Can't overwrite \"%s\"\n", name);
return 1;
} else if (item->flags &
ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR) {
const char *defval = getenv_default(name);
if (defval == NULL)
defval = "";
printf("oldval: %s defval: %s\n", oldval, defval);
if (strcmp(oldval, defval) != 0) {
printf("## Error: Can't overwrite \"%s\"\n",
name);
return 1;
}
}
break;
case env_op_create:
if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_CREATE) {
printf("## Error: Can't create \"%s\"\n", name);
return 1;
}
break;
}
return 0;
}

50
include/env_flags.h
View file

@ -36,9 +36,18 @@ enum env_flags_vartype {
env_flags_vartype_end
};
enum env_flags_varaccess {
env_flags_varaccess_any,
env_flags_varaccess_readonly,
env_flags_varaccess_writeonce,
env_flags_varaccess_changedefault,
env_flags_varaccess_end
};
#define ENV_FLAGS_VAR ".flags"
#define ENV_FLAGS_ATTR_MAX_LEN 2
#define ENV_FLAGS_VARTYPE_LOC 0
#define ENV_FLAGS_VARACCESS_LOC 1
#ifndef CONFIG_ENV_FLAGS_LIST_STATIC
#define CONFIG_ENV_FLAGS_LIST_STATIC ""
@ -52,27 +61,57 @@ enum env_flags_vartype {
* Print the whole list of available type flags.
*/
void env_flags_print_vartypes(void);
/*
* Print the whole list of available access flags.
*/
void env_flags_print_varaccess(void);
/*
* Return the name of the type.
*/
const char *env_flags_get_vartype_name(enum env_flags_vartype type);
/*
* Return the name of the access.
*/
const char *env_flags_get_varaccess_name(enum env_flags_varaccess access);
#endif
/*
* Parse the flags string from a .flags attribute list into the vartype enum.
*/
enum env_flags_vartype env_flags_parse_vartype(const char *flags);
/*
* Parse the flags string from a .flags attribute list into the varaccess enum.
*/
enum env_flags_varaccess env_flags_parse_varaccess(const char *flags);
/*
* Parse the binary flags from a hash table entry into the varaccess enum.
*/
enum env_flags_varaccess env_flags_parse_varaccess_from_binflags(int binflags);
#ifdef USE_HOSTCC
/*
* Look up the type of a variable directly from the .flags var.
*/
enum env_flags_vartype env_flags_get_type(const char *name);
/*
* Look up the access of a variable directly from the .flags var.
*/
enum env_flags_varaccess env_flags_get_access(const char *name);
/*
* Validate the newval for its type to conform with the requirements defined by
* its flags (directly looked at the .flags var).
*/
int env_flags_validate_type(const char *name, const char *newval);
/*
* Validate the newval for its access to conform with the requirements defined
* by its flags (directly looked at the .flags var).
*/
int env_flags_validate_access(const char *name, int check_mask);
/*
* Validate that the proposed access to variable "name" is valid according to
* the defined flags for that variable, if any.
*/
int env_flags_validate_varaccess(const char *name, int check_mask);
/*
* Validate the parameters passed to "env set" for type compliance
*/
@ -94,13 +133,18 @@ void env_flags_init(ENTRY *var_entry);
int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
int flag);
#endif /* USE_HOSTCC */
/*
* These are the binary flags used in the environment entry->flags variable to
* decribe properties of veriables in the table
*/
#define ENV_FLAGS_VARTYPE_BIN_MASK 0x00000007
#define ENV_FLAGS_VARTYPE_BIN_MASK 0x00000007
/* The actual variable type values use the enum value (within the mask) */
#endif /* USE_HOSTCC */
#define ENV_FLAGS_VARACCESS_PREVENT_DELETE 0x00000008
#define ENV_FLAGS_VARACCESS_PREVENT_CREATE 0x00000010
#define ENV_FLAGS_VARACCESS_PREVENT_OVERWR 0x00000020
#define ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR 0x00000040
#define ENV_FLAGS_VARACCESS_BIN_MASK 0x00000078
#endif /* __ENV_FLAGS_H__ */

3
include/environment.h
View file

@ -181,6 +181,9 @@ unsigned char env_get_char_memory(int index);
/* Function that updates CRC of the enironment */
void env_crc_update(void);
/* Look up the variable from the default environment */
char *getenv_default(const char *name);
/* [re]set to the default environment */
void set_default_env(const char *s);

74
tools/env/fw_env.c vendored
View file

@ -181,6 +181,32 @@ char *fw_getenv (char *name)
return NULL;
}
/*
* Search the default environment for a variable.
* Return the value, if found, or NULL, if not found.
*/
char *fw_getdefenv(char *name)
{
char *env, *nxt;
for (env = default_environment; *env; env = nxt + 1) {
char *val;
for (nxt = env; *nxt; ++nxt) {
if (nxt >= &default_environment[ENV_SIZE]) {
fprintf(stderr, "## Error: "
"default environment not terminated\n");
return NULL;
}
}
val = envmatch(name, env);
if (!val)
continue;
return val;
}
return NULL;
}
/*
* Print the current definition of one, or more, or all
* environment variables
@ -282,6 +308,7 @@ int fw_env_write(char *name, char *value)
int len;
char *env, *nxt;
char *oldval = NULL;
int deleting, creating, overwriting;
/*
* search if variable with this name already exists
@ -299,10 +326,49 @@ int fw_env_write(char *name, char *value)
break;
}
/*
* Delete any existing definition
*/
if (oldval) {
deleting = (oldval && !(value && strlen(value)));
creating = (!oldval && (value && strlen(value)));
overwriting = (oldval && (value && strlen(value)));
/* check for permission */
if (deleting) {
if (env_flags_validate_varaccess(name,
ENV_FLAGS_VARACCESS_PREVENT_DELETE)) {
printf("Can't delete \"%s\"\n", name);
errno = EROFS;
return -1;
}
} else if (overwriting) {
if (env_flags_validate_varaccess(name,
ENV_FLAGS_VARACCESS_PREVENT_OVERWR)) {
printf("Can't overwrite \"%s\"\n", name);
errno = EROFS;
return -1;
} else if (env_flags_validate_varaccess(name,
ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR)) {
const char *defval = fw_getdefenv(name);
if (defval == NULL)
defval = "";
if (strcmp(oldval, defval)
!= 0) {
printf("Can't overwrite \"%s\"\n", name);
errno = EROFS;
return -1;
}
}
} else if (creating) {
if (env_flags_validate_varaccess(name,
ENV_FLAGS_VARACCESS_PREVENT_CREATE)) {
printf("Can't create \"%s\"\n", name);
errno = EROFS;
return -1;
}
} else
/* Nothing to do */
return 0;
if (deleting || overwriting) {
#ifndef CONFIG_ENV_OVERWRITE
/*
* Ethernet Address and serial# can be set only once