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checkseapp: generalize input validation

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Input validation was hard-coded into a validation routine
that would check against type and key names in a scattered,
order dependent conditional code block.

This makes it harder than it should be to add new key value
pairs and types into checkseapp.

To correct this, we add a validation callback into the
static mapping. If the validation callback is set, the
existing validation routine will call this for input
validation. On failure, a validation specific error message
is returned to be displayed.

Change-Id: I92cf1cdf4ddbcfae19168b621f47169a3cf551ac
Signed-off-by: William Roberts <william.c.roberts@intel.com>
This commit is contained in:
William Roberts 2016-01-29 10:41:50 -08:00
parent efebf97e23
commit 696a66ba20
1 changed files with 83 additions and 58 deletions
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141
tools/check_seapp.c
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@ -113,6 +113,7 @@ struct key_map {
data_type type;
char *data;
key_map_regex regex;
bool (*fn_validate)(char *value, char **errmsg);
};
/**
@ -197,25 +198,31 @@ static list line_order_list = list_init(line_order_list_freefn);
*/
static list nallow_list = list_init(line_order_list_freefn);
/* validation call backs */
static bool validate_bool(char *value, char **errmsg);
static bool validate_levelFrom(char *value, char **errmsg);
static bool validate_selinux_type(char *value, char **errmsg);
static bool validate_selinux_level(char *value, char **errmsg);
/**
* The heart of the mapping process, this must be updated if a new key value pair is added
* to a rule.
*/
key_map rules[] = {
/*Inputs*/
{ .name = "isSystemServer", .type = dt_bool, .dir = dir_in, .data = NULL },
{ .name = "isOwner", .type = dt_bool, .dir = dir_in, .data = NULL },
{ .name = "user", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "seinfo", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "name", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "path", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "isPrivApp", .type = dt_bool, .dir = dir_in, .data = NULL },
{ .name = "isSystemServer", .type = dt_bool, .dir = dir_in, .data = NULL, .fn_validate = validate_bool },
{ .name = "isOwner", .type = dt_bool, .dir = dir_in, .data = NULL, .fn_validate = validate_bool },
{ .name = "user", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "seinfo", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "name", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "path", .type = dt_string, .dir = dir_in, .data = NULL },
{ .name = "isPrivApp", .type = dt_bool, .dir = dir_in, .data = NULL, .fn_validate = validate_bool },
/*Outputs*/
{ .name = "domain", .type = dt_string, .dir = dir_out, .data = NULL },
{ .name = "type", .type = dt_string, .dir = dir_out, .data = NULL },
{ .name = "levelFromUid", .type = dt_bool, .dir = dir_out, .data = NULL },
{ .name = "levelFrom", .type = dt_string, .dir = dir_out, .data = NULL },
{ .name = "level", .type = dt_string, .dir = dir_out, .data = NULL },
{ .name = "domain", .type = dt_string, .dir = dir_out, .data = NULL, .fn_validate = validate_selinux_type },
{ .name = "type", .type = dt_string, .dir = dir_out, .data = NULL, .fn_validate = validate_selinux_type },
{ .name = "levelFromUid", .type = dt_bool, .dir = dir_out, .data = NULL, .fn_validate = validate_bool },
{ .name = "levelFrom", .type = dt_string, .dir = dir_out, .data = NULL, .fn_validate = validate_levelFrom },
{ .name = "level", .type = dt_string, .dir = dir_out, .data = NULL, .fn_validate = validate_selinux_level },
};
/**
@ -352,6 +359,63 @@ static bool compile_regex(key_map *km, const char **errbuf, int *erroff) {
return true;
}
static bool validate_bool(char *value, char **errmsg) {
if (!strcmp("true", value) || !strcmp("false", value)) {
return true;
}
*errmsg = "Expecting \"true\" or \"false\"";
return false;
}
static bool validate_levelFrom(char *value, char **errmsg) {
if(strcasecmp(value, "none") && strcasecmp(value, "all") &&
strcasecmp(value, "app") && strcasecmp(value, "user")) {
*errmsg = "Expecting one of: \"none\", \"all\", \"app\" or \"user\"";
return false;
}
return true;
}
static bool validate_selinux_type(char *value, char **errmsg) {
/*
* No policy file present means we cannot check
* SE Linux types
*/
if (!pol.policy_file) {
return true;
}
if(!check_type(pol.db, value)) {
*errmsg = "Expecting a valid SELinux type";
return false;
}
return true;
}
static bool validate_selinux_level(char *value, char **errmsg) {
/*
* No policy file present means we cannot check
* SE Linux MLS
*/
if (!pol.policy_file) {
return true;
}
int ret = sepol_mls_check(pol.handle, pol.db, value);
if (ret < 0) {
*errmsg = "Expecting a valid SELinux MLS value";
return false;
}
return true;
}
/**
* Validates a key_map against a set of enforcement rules, this
* function exits the application on a type that cannot be properly
@ -370,10 +434,9 @@ static bool key_map_validate(key_map *m, const char *filename, int lineno,
int erroff;
const char *errbuf;
bool rc = true;
int ret = 1;
char *key = m->name;
char *value = m->data;
data_type type = m->type;
char *errmsg = NULL;
log_info("Validating %s=%s\n", key, value);
@ -392,51 +455,13 @@ static bool key_map_validate(key_map *m, const char *filename, int lineno,
goto out;
}
/* Booleans can always be checked for sanity */
if (type == dt_bool && (!strcmp("true", value) || !strcmp("false", value))) {
goto out;
}
else if (type == dt_bool) {
log_error("Expected boolean value got: %s=%s on line: %d in file: %s\n",
key, value, lineno, filename);
rc = false;
goto out;
}
/* If the key has a validation routine, call it */
if (m->fn_validate) {
rc = m->fn_validate(value, &errmsg);
if (!strcasecmp(key, "levelFrom") &&
(strcasecmp(value, "none") && strcasecmp(value, "all") &&
strcasecmp(value, "app") && strcasecmp(value, "user"))) {
log_error("Unknown levelFrom=%s on line: %d in file: %s\n",
value, lineno, filename);
rc = false;
goto out;
}
/*
* If there is no policy file present,
* then it is not going to enforce the types against the policy so just return.
* User and name cannot really be checked.
*/
if (!pol.policy_file) {
goto out;
}
else if (!strcasecmp(key, "type") || !strcasecmp(key, "domain")) {
if(!check_type(pol.db, value)) {
log_error("Could not find selinux type \"%s\" on line: %d in file: %s\n", value,
lineno, filename);
rc = false;
}
goto out;
}
else if (!strcasecmp(key, "level")) {
ret = sepol_mls_check(pol.handle, pol.db, value);
if (ret < 0) {
log_error("Could not find selinux level \"%s\", on line: %d in file: %s\n", value,
lineno, filename);
rc = false;
goto out;
if (!rc) {
log_error("Could not validate key \"%s\" for value \"%s\" on line: %d in file: \"%s\": %s\n", key, value,
lineno, filename, errmsg);
}
}