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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2011-09-10 15:22:48 +0900
committerJames Morris <jmorris@namei.org>2011-09-14 08:27:05 +1000
commitd58e0da854376841ac99defeb117a83f086715c6 (patch)
treeb6e37d1030180680a7801ecb295d8d3990930375 /security/tomoyo/environ.c
parent5dbe3040c74eef18e66951347eda05b153e69328 (diff)
downloadlinux-linaro-stable-d58e0da854376841ac99defeb117a83f086715c6.tar.gz
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 <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/tomoyo/environ.c')
-rw-r--r--security/tomoyo/environ.c122
1 files changed, 122 insertions, 0 deletions
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(&param->data, "env "))
+ return tomoyo_write_env(param);
+ return -EINVAL;
+}