From d58e0da854376841ac99defeb117a83f086715c6 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sat, 10 Sep 2011 15:22:48 +0900 Subject: TOMOYO: Add environment variable name restriction support. This patch adds support for checking environment variable's names. Although TOMOYO already provides ability to check argv[]/envp[] passed to execve() requests, file execute /bin/sh exec.envp["LD_LIBRARY_PATH"]="bar" will reject execution of /bin/sh if environment variable LD_LIBRARY_PATH is not defined. To grant execution of /bin/sh if LD_LIBRARY_PATH is not defined, administrators have to specify like file execute /bin/sh exec.envp["LD_LIBRARY_PATH"]="/system/lib" file execute /bin/sh exec.envp["LD_LIBRARY_PATH"]=NULL . Since there are many environment variables whereas conditional checks are applied as "&&", it is difficult to cover all combinations. Therefore, this patch supports conditional checks that are applied as "||", by specifying like file execute /bin/sh misc env LD_LIBRARY_PATH exec.envp["LD_LIBRARY_PATH"]="/system/lib" which means "grant execution of /bin/sh if environment variable is not defined or is defined and its value is /system/lib". Signed-off-by: Tetsuo Handa Signed-off-by: James Morris --- security/tomoyo/environ.c | 122 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 security/tomoyo/environ.c (limited to 'security/tomoyo/environ.c') diff --git a/security/tomoyo/environ.c b/security/tomoyo/environ.c new file mode 100644 index 000000000000..ad4c6e18a437 --- /dev/null +++ b/security/tomoyo/environ.c @@ -0,0 +1,122 @@ +/* + * security/tomoyo/environ.c + * + * Copyright (C) 2005-2011 NTT DATA CORPORATION + */ + +#include "common.h" + +/** + * tomoyo_check_env_acl - Check permission for environment variable's name. + * + * @r: Pointer to "struct tomoyo_request_info". + * @ptr: Pointer to "struct tomoyo_acl_info". + * + * Returns true if granted, false otherwise. + */ +static bool tomoyo_check_env_acl(struct tomoyo_request_info *r, + const struct tomoyo_acl_info *ptr) +{ + const struct tomoyo_env_acl *acl = + container_of(ptr, typeof(*acl), head); + + return tomoyo_path_matches_pattern(r->param.environ.name, acl->env); +} + +/** + * tomoyo_audit_env_log - Audit environment variable name log. + * + * @r: Pointer to "struct tomoyo_request_info". + * + * Returns 0 on success, negative value otherwise. + */ +static int tomoyo_audit_env_log(struct tomoyo_request_info *r) +{ + return tomoyo_supervisor(r, "misc env %s\n", + r->param.environ.name->name); +} + +/** + * tomoyo_env_perm - Check permission for environment variable's name. + * + * @r: Pointer to "struct tomoyo_request_info". + * @env: The name of environment variable. + * + * Returns 0 on success, negative value otherwise. + * + * Caller holds tomoyo_read_lock(). + */ +int tomoyo_env_perm(struct tomoyo_request_info *r, const char *env) +{ + struct tomoyo_path_info environ; + int error; + + if (!env || !*env) + return 0; + environ.name = env; + tomoyo_fill_path_info(&environ); + r->param_type = TOMOYO_TYPE_ENV_ACL; + r->param.environ.name = &environ; + do { + tomoyo_check_acl(r, tomoyo_check_env_acl); + error = tomoyo_audit_env_log(r); + } while (error == TOMOYO_RETRY_REQUEST); + return error; +} + +/** + * tomoyo_same_env_acl - Check for duplicated "struct tomoyo_env_acl" entry. + * + * @a: Pointer to "struct tomoyo_acl_info". + * @b: Pointer to "struct tomoyo_acl_info". + * + * Returns true if @a == @b, false otherwise. + */ +static bool tomoyo_same_env_acl(const struct tomoyo_acl_info *a, + const struct tomoyo_acl_info *b) +{ + const struct tomoyo_env_acl *p1 = container_of(a, typeof(*p1), head); + const struct tomoyo_env_acl *p2 = container_of(b, typeof(*p2), head); + + return p1->env == p2->env; +} + +/** + * tomoyo_write_env - Write "struct tomoyo_env_acl" list. + * + * @param: Pointer to "struct tomoyo_acl_param". + * + * Returns 0 on success, negative value otherwise. + * + * Caller holds tomoyo_read_lock(). + */ +static int tomoyo_write_env(struct tomoyo_acl_param *param) +{ + struct tomoyo_env_acl e = { .head.type = TOMOYO_TYPE_ENV_ACL }; + int error = -ENOMEM; + const char *data = tomoyo_read_token(param); + + if (!tomoyo_correct_word(data) || strchr(data, '=')) + return -EINVAL; + e.env = tomoyo_get_name(data); + if (!e.env) + return error; + error = tomoyo_update_domain(&e.head, sizeof(e), param, + tomoyo_same_env_acl, NULL); + tomoyo_put_name(e.env); + return error; +} + +/** + * tomoyo_write_misc - Update environment variable list. + * + * @param: Pointer to "struct tomoyo_acl_param". + * + * Returns 0 on success, negative value otherwise. + */ +int tomoyo_write_misc(struct tomoyo_acl_param *param) +{ + if (tomoyo_str_starts(¶m->data, "env ")) + return tomoyo_write_env(param); + return -EINVAL; +} -- cgit v1.2.3