From 731d37aa70c7b9de3be6bf2c8287366223bf5ce5 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Sat, 10 Sep 2011 15:25:58 +0900 Subject: TOMOYO: Allow domain transition without execve(). To be able to split permissions for Apache's CGI programs which are executed without execve(), add special domain transition which is performed by writing a TOMOYO's domainname to /sys/kernel/security/tomoyo/self_domain interface. This is an API for TOMOYO-aware userland applications. However, since I expect TOMOYO and other LSM modules to run in parallel, this patch does not use /proc/self/attr/ interface in order to avoid conflicts with other LSM modules when it became possible to run multiple LSM modules in parallel. Signed-off-by: Tetsuo Handa Signed-off-by: James Morris --- security/tomoyo/securityfs_if.c | 122 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 120 insertions(+), 2 deletions(-) (limited to 'security/tomoyo/securityfs_if.c') diff --git a/security/tomoyo/securityfs_if.c b/security/tomoyo/securityfs_if.c index a49c3bfd4dd5..d08296a4882b 100644 --- a/security/tomoyo/securityfs_if.c +++ b/security/tomoyo/securityfs_if.c @@ -7,6 +7,124 @@ #include #include "common.h" +/** + * tomoyo_check_task_acl - Check permission for task operation. + * + * @r: Pointer to "struct tomoyo_request_info". + * @ptr: Pointer to "struct tomoyo_acl_info". + * + * Returns true if granted, false otherwise. + */ +static bool tomoyo_check_task_acl(struct tomoyo_request_info *r, + const struct tomoyo_acl_info *ptr) +{ + const struct tomoyo_task_acl *acl = container_of(ptr, typeof(*acl), + head); + return !tomoyo_pathcmp(r->param.task.domainname, acl->domainname); +} + +/** + * tomoyo_write_self - write() for /sys/kernel/security/tomoyo/self_domain interface. + * + * @file: Pointer to "struct file". + * @buf: Domainname to transit to. + * @count: Size of @buf. + * @ppos: Unused. + * + * Returns @count on success, negative value otherwise. + * + * If domain transition was permitted but the domain transition failed, this + * function returns error rather than terminating current thread with SIGKILL. + */ +static ssize_t tomoyo_write_self(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + char *data; + int error; + if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10) + return -ENOMEM; + data = kzalloc(count + 1, GFP_NOFS); + if (!data) + return -ENOMEM; + if (copy_from_user(data, buf, count)) { + error = -EFAULT; + goto out; + } + tomoyo_normalize_line(data); + if (tomoyo_correct_domain(data)) { + const int idx = tomoyo_read_lock(); + struct tomoyo_path_info name; + struct tomoyo_request_info r; + name.name = data; + tomoyo_fill_path_info(&name); + /* Check "task manual_domain_transition" permission. */ + tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE); + r.param_type = TOMOYO_TYPE_MANUAL_TASK_ACL; + r.param.task.domainname = &name; + tomoyo_check_acl(&r, tomoyo_check_task_acl); + if (!r.granted) + error = -EPERM; + else { + struct tomoyo_domain_info *new_domain = + tomoyo_assign_domain(data, true); + if (!new_domain) { + error = -ENOENT; + } else { + struct cred *cred = prepare_creds(); + if (!cred) { + error = -ENOMEM; + } else { + struct tomoyo_domain_info *old_domain = + cred->security; + cred->security = new_domain; + atomic_inc(&new_domain->users); + atomic_dec(&old_domain->users); + commit_creds(cred); + error = 0; + } + } + } + tomoyo_read_unlock(idx); + } else + error = -EINVAL; +out: + kfree(data); + return error ? error : count; +} + +/** + * tomoyo_read_self - read() for /sys/kernel/security/tomoyo/self_domain interface. + * + * @file: Pointer to "struct file". + * @buf: Domainname which current thread belongs to. + * @count: Size of @buf. + * @ppos: Bytes read by now. + * + * Returns read size on success, negative value otherwise. + */ +static ssize_t tomoyo_read_self(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + const char *domain = tomoyo_domain()->domainname->name; + loff_t len = strlen(domain); + loff_t pos = *ppos; + if (pos >= len || !count) + return 0; + len -= pos; + if (count < len) + len = count; + if (copy_to_user(buf, domain + pos, len)) + return -EFAULT; + *ppos += len; + return len; +} + +/* Operations for /sys/kernel/security/tomoyo/self_domain interface. */ +static const struct file_operations tomoyo_self_operations = { + .write = tomoyo_write_self, + .read = tomoyo_read_self, +}; + /** * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface. * @@ -135,8 +253,6 @@ static int __init tomoyo_initerface_init(void) TOMOYO_EXCEPTIONPOLICY); tomoyo_create_entry("audit", 0400, tomoyo_dir, TOMOYO_AUDIT); - tomoyo_create_entry("self_domain", 0400, tomoyo_dir, - TOMOYO_SELFDOMAIN); tomoyo_create_entry(".process_status", 0600, tomoyo_dir, TOMOYO_PROCESS_STATUS); tomoyo_create_entry("stat", 0644, tomoyo_dir, @@ -147,6 +263,8 @@ static int __init tomoyo_initerface_init(void) TOMOYO_MANAGER); tomoyo_create_entry("version", 0400, tomoyo_dir, TOMOYO_VERSION); + securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL, + &tomoyo_self_operations); return 0; } -- cgit