Merge tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

Pull audit updates from Paul Moore:
 "A lucky 13 audit patches for v5.1.

  Despite the rather large diffstat, most of the changes are from two
  bug fix patches that move code from one Kconfig option to another.

  Beyond that bit of churn, the remaining changes are largely cleanups
  and bug-fixes as we slowly march towards container auditing. It isn't
  all boring though, we do have a couple of new things: file
  capabilities v3 support, and expanded support for filtering on
  filesystems to solve problems with remote filesystems.

  All changes pass the audit-testsuite.  Please merge for v5.1"

* tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: mark expected switch fall-through
  audit: hide auditsc_get_stamp and audit_serial prototypes
  audit: join tty records to their syscall
  audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL
  audit: remove unused actx param from audit_rule_match
  audit: ignore fcaps on umount
  audit: clean up AUDITSYSCALL prototypes and stubs
  audit: more filter PATH records keyed on filesystem magic
  audit: add support for fcaps v3
  audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDIT
  audit: add syscall information to CONFIG_CHANGE records
  audit: hand taken context to audit_kill_trees for syscall logging
  audit: give a clue what CONFIG_CHANGE op was involved

1 files changed, 109 insertions, 158 deletions

diff --git a/kernel/audit.c b/kernel/audit.c
index 632d36059556..c89ea48c70a6 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -396,10 +396,10 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old,
         struct audit_buffer *ab;
         int rc = 0;
 
-        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
+        ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
         if (unlikely(!ab))
                 return rc;
-        audit_log_format(ab, "%s=%u old=%u ", function_name, new, old);
+        audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
         audit_log_session_info(ab);
         rc = audit_log_task_context(ab);
         if (rc)
@@ -1053,7 +1053,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
         return err;
 }
 
-static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
+static void audit_log_common_recv_msg(struct audit_context *context,
+                                        struct audit_buffer **ab, u16 msg_type)
 {
         uid_t uid = from_kuid(&init_user_ns, current_uid());
         pid_t pid = task_tgid_nr(current);
@@ -1063,7 +1064,7 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
                 return;
         }
 
-        *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
+        *ab = audit_log_start(context, GFP_KERNEL, msg_type);
         if (unlikely(!*ab))
                 return;
         audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
@@ -1071,6 +1072,12 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
         audit_log_task_context(*ab);
 }
 
+static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
+                                           u16 msg_type)
+{
+        audit_log_common_recv_msg(NULL, ab, msg_type);
+}
+
 int is_audit_feature_set(int i)
 {
         return af.features & AUDIT_FEATURE_TO_MASK(i);
@@ -1338,7 +1345,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                                 if (err)
                                         break;
                         }
-                        audit_log_common_recv_msg(&ab, msg_type);
+                        audit_log_user_recv_msg(&ab, msg_type);
                         if (msg_type != AUDIT_USER_TTY)
                                 audit_log_format(ab, " msg='%.*s'",
                                                  AUDIT_MESSAGE_TEXT_MAX,
@@ -1361,8 +1368,12 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
                         return -EINVAL;
                 if (audit_enabled == AUDIT_LOCKED) {
-                        audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
-                        audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
+                        audit_log_common_recv_msg(audit_context(), &ab,
+                                                  AUDIT_CONFIG_CHANGE);
+                        audit_log_format(ab, " op=%s audit_enabled=%d res=0",
+                                         msg_type == AUDIT_ADD_RULE ?
+                                                "add_rule" : "remove_rule",
+                                         audit_enabled);
                         audit_log_end(ab);
                         return -EPERM;
                 }
@@ -1373,7 +1384,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 break;
         case AUDIT_TRIM:
                 audit_trim_trees();
-                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+                audit_log_common_recv_msg(audit_context(), &ab,
+                                          AUDIT_CONFIG_CHANGE);
                 audit_log_format(ab, " op=trim res=1");
                 audit_log_end(ab);
                 break;
@@ -1403,8 +1415,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 /* OK, here comes... */
                 err = audit_tag_tree(old, new);
 
-                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
-
+                audit_log_common_recv_msg(audit_context(), &ab,
+                                          AUDIT_CONFIG_CHANGE);
                 audit_log_format(ab, " op=make_equiv old=");
                 audit_log_untrustedstring(ab, old);
                 audit_log_format(ab, " new=");
@@ -1471,7 +1483,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
                 old.enabled = t & AUDIT_TTY_ENABLE;
                 old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
 
-                audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
+                audit_log_common_recv_msg(audit_context(), &ab,
+                                          AUDIT_CONFIG_CHANGE);
                 audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
                                  " old-log_passwd=%d new-log_passwd=%d res=%d",
                                  old.enabled, s.enabled, old.log_passwd,
@@ -2054,153 +2067,6 @@ void audit_log_key(struct audit_buffer *ab, char *key)
                 audit_log_format(ab, "(null)");
 }
 
-void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
-{
-        int i;
-
-        if (cap_isclear(*cap)) {
-                audit_log_format(ab, " %s=0", prefix);
-                return;
-        }
-        audit_log_format(ab, " %s=", prefix);
-        CAP_FOR_EACH_U32(i)
-                audit_log_format(ab, "%08x", cap->cap[CAP_LAST_U32 - i]);
-}
-
-static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
-{
-        audit_log_cap(ab, "cap_fp", &name->fcap.permitted);
-        audit_log_cap(ab, "cap_fi", &name->fcap.inheritable);
-        audit_log_format(ab, " cap_fe=%d cap_fver=%x",
-                         name->fcap.fE, name->fcap_ver);
-}
-
-static inline int audit_copy_fcaps(struct audit_names *name,
-                                   const struct dentry *dentry)
-{
-        struct cpu_vfs_cap_data caps;
-        int rc;
-
-        if (!dentry)
-                return 0;
-
-        rc = get_vfs_caps_from_disk(dentry, &caps);
-        if (rc)
-                return rc;
-
-        name->fcap.permitted = caps.permitted;
-        name->fcap.inheritable = caps.inheritable;
-        name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
-        name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
-                                VFS_CAP_REVISION_SHIFT;
-
-        return 0;
-}
-
-/* Copy inode data into an audit_names. */
-void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
-                      struct inode *inode)
-{
-        name->ino   = inode->i_ino;
-        name->dev   = inode->i_sb->s_dev;
-        name->mode  = inode->i_mode;
-        name->uid   = inode->i_uid;
-        name->gid   = inode->i_gid;
-        name->rdev  = inode->i_rdev;
-        security_inode_getsecid(inode, &name->osid);
-        audit_copy_fcaps(name, dentry);
-}
-
-/**
- * audit_log_name - produce AUDIT_PATH record from struct audit_names
- * @context: audit_context for the task
- * @n: audit_names structure with reportable details
- * @path: optional path to report instead of audit_names->name
- * @record_num: record number to report when handling a list of names
- * @call_panic: optional pointer to int that will be updated if secid fails
- */
-void audit_log_name(struct audit_context *context, struct audit_names *n,
-                    const struct path *path, int record_num, int *call_panic)
-{
-        struct audit_buffer *ab;
-        ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
-        if (!ab)
-                return;
-
-        audit_log_format(ab, "item=%d", record_num);
-
-        if (path)
-                audit_log_d_path(ab, " name=", path);
-        else if (n->name) {
-                switch (n->name_len) {
-                case AUDIT_NAME_FULL:
-                        /* log the full path */
-                        audit_log_format(ab, " name=");
-                        audit_log_untrustedstring(ab, n->name->name);
-                        break;
-                case 0:
-                        /* name was specified as a relative path and the
-                         * directory component is the cwd */
-                        audit_log_d_path(ab, " name=", &context->pwd);
-                        break;
-                default:
-                        /* log the name's directory component */
-                        audit_log_format(ab, " name=");
-                        audit_log_n_untrustedstring(ab, n->name->name,
-                                                    n->name_len);
-                }
-        } else
-                audit_log_format(ab, " name=(null)");
-
-        if (n->ino != AUDIT_INO_UNSET)
-                audit_log_format(ab, " inode=%lu"
-                                 " dev=%02x:%02x mode=%#ho"
-                                 " ouid=%u ogid=%u rdev=%02x:%02x",
-                                 n->ino,
-                                 MAJOR(n->dev),
-                                 MINOR(n->dev),
-                                 n->mode,
-                                 from_kuid(&init_user_ns, n->uid),
-                                 from_kgid(&init_user_ns, n->gid),
-                                 MAJOR(n->rdev),
-                                 MINOR(n->rdev));
-        if (n->osid != 0) {
-                char *ctx = NULL;
-                u32 len;
-                if (security_secid_to_secctx(
-                        n->osid, &ctx, &len)) {
-                        audit_log_format(ab, " osid=%u", n->osid);
-                        if (call_panic)
-                                *call_panic = 2;
-                } else {
-                        audit_log_format(ab, " obj=%s", ctx);
-                        security_release_secctx(ctx, len);
-                }
-        }
-
-        /* log the audit_names record type */
-        switch(n->type) {
-        case AUDIT_TYPE_NORMAL:
-                audit_log_format(ab, " nametype=NORMAL");
-                break;
-        case AUDIT_TYPE_PARENT:
-                audit_log_format(ab, " nametype=PARENT");
-                break;
-        case AUDIT_TYPE_CHILD_DELETE:
-                audit_log_format(ab, " nametype=DELETE");
-                break;
-        case AUDIT_TYPE_CHILD_CREATE:
-                audit_log_format(ab, " nametype=CREATE");
-                break;
-        default:
-                audit_log_format(ab, " nametype=UNKNOWN");
-                break;
-        }
-
-        audit_log_fcaps(ab, n);
-        audit_log_end(ab);
-}
-
 int audit_log_task_context(struct audit_buffer *ab)
 {
         char *ctx = NULL;
@@ -2322,6 +2188,91 @@ void audit_log_link_denied(const char *operation)
         audit_log_end(ab);
 }
 
+/* global counter which is incremented every time something logs in */
+static atomic_t session_id = ATOMIC_INIT(0);
+
+static int audit_set_loginuid_perm(kuid_t loginuid)
+{
+        /* if we are unset, we don't need privs */
+        if (!audit_loginuid_set(current))
+                return 0;
+        /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
+        if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
+                return -EPERM;
+        /* it is set, you need permission */
+        if (!capable(CAP_AUDIT_CONTROL))
+                return -EPERM;
+        /* reject if this is not an unset and we don't allow that */
+        if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
+                                 && uid_valid(loginuid))
+                return -EPERM;
+        return 0;
+}
+
+static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
+                                   unsigned int oldsessionid,
+                                   unsigned int sessionid, int rc)
+{
+        struct audit_buffer *ab;
+        uid_t uid, oldloginuid, loginuid;
+        struct tty_struct *tty;
+
+        if (!audit_enabled)
+                return;
+
+        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
+        if (!ab)
+                return;
+
+        uid = from_kuid(&init_user_ns, task_uid(current));
+        oldloginuid = from_kuid(&init_user_ns, koldloginuid);
+        loginuid = from_kuid(&init_user_ns, kloginuid),
+        tty = audit_get_tty();
+
+        audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
+        audit_log_task_context(ab);
+        audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
+                         oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
+                         oldsessionid, sessionid, !rc);
+        audit_put_tty(tty);
+        audit_log_end(ab);
+}
+
+/**
+ * audit_set_loginuid - set current task's loginuid
+ * @loginuid: loginuid value
+ *
+ * Returns 0.
+ *
+ * Called (set) from fs/proc/base.c::proc_loginuid_write().
+ */
+int audit_set_loginuid(kuid_t loginuid)
+{
+        unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
+        kuid_t oldloginuid;
+        int rc;
+
+        oldloginuid = audit_get_loginuid(current);
+        oldsessionid = audit_get_sessionid(current);
+
+        rc = audit_set_loginuid_perm(loginuid);
+        if (rc)
+                goto out;
+
+        /* are we setting or clearing? */
+        if (uid_valid(loginuid)) {
+                sessionid = (unsigned int)atomic_inc_return(&session_id);
+                if (unlikely(sessionid == AUDIT_SID_UNSET))
+                        sessionid = (unsigned int)atomic_inc_return(&session_id);
+        }
+
+        current->sessionid = sessionid;
+        current->loginuid = loginuid;
+out:
+        audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
+        return rc;
+}
+
 /**
  * audit_log_end - end one audit record
  * @ab: the audit_buffer