When the capset syscall is used it is not possible for audit to record the

actual capbilities being added/removed.  This patch adds a new record type
which emits the target pid and the eff, inh, and perm cap sets.

example output if you audit capset syscalls would be:

type=SYSCALL msg=audit(1225743140.465:76): arch=c000003e syscall=126 success=yes exit=0 a0=17f2014 a1=17f201c a2=80000000 a3=7fff2ab7f060 items=0 ppid=2160 pid=2223 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=1 comm="setcap" exe="/usr/sbin/setcap" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1322] msg=audit(1225743140.465:76): pid=0 cap_pi=ffffffffffffffff cap_pp=ffffffffffffffff cap_pe=ffffffffffffffff

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

3 files changed, 63 insertions, 0 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 8cfb9feb2a05..6fbebac7b1bf 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -100,6 +100,7 @@
 #define AUDIT_TTY               1319    /* Input on an administrative TTY */
 #define AUDIT_EOE               1320    /* End of multi-record event */
 #define AUDIT_BPRM_FCAPS        1321    /* Information about fcaps increasing perms */
+#define AUDIT_CAPSET            1322    /* Record showing argument to sys_capset */
 
 #define AUDIT_AVC               1400    /* SE Linux avc denial or grant */
 #define AUDIT_SELINUX_ERR       1401    /* Internal SE Linux Errors */
@@ -454,6 +455,7 @@ extern int __audit_mq_timedreceive(mqd_t mqdes, size_t msg_len, unsigned int __u
 extern int __audit_mq_notify(mqd_t mqdes, const struct sigevent __user *u_notification);
 extern int __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat);
 extern void __audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t *pP, kernel_cap_t *pE);
+extern int __audit_log_capset(pid_t pid, kernel_cap_t *eff, kernel_cap_t *inh, kernel_cap_t *perm);
 
 static inline int audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
@@ -526,6 +528,13 @@ static inline void audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t
                 __audit_log_bprm_fcaps(bprm, pP, pE);
 }
 
+static inline int audit_log_capset(pid_t pid, kernel_cap_t *eff, kernel_cap_t *inh, kernel_cap_t *perm)
+{
+        if (unlikely(!audit_dummy_context()))
+                return __audit_log_capset(pid, eff, inh, perm);
+        return 0;
+}
+
 extern int audit_n_rules;
 extern int audit_signals;
 #else
@@ -558,6 +567,7 @@ extern int audit_signals;
 #define audit_mq_notify(d,n) ({ 0; })
 #define audit_mq_getsetattr(d,s) ({ 0; })
 #define audit_log_bprm_fcaps(b, p, e) do { ; } while (0)
+#define audit_log_capset(pid, e, i, p) ({ 0; })
 #define audit_ptrace(t) ((void)0)
 #define audit_n_rules 0
 #define audit_signals 0
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3229cd4206f5..cef34235b362 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -204,6 +204,12 @@ struct audit_aux_data_bprm_fcaps {
         struct audit_cap_data   new_pcap;
 };
 
+struct audit_aux_data_capset {
+        struct audit_aux_data   d;
+        pid_t                   pid;
+        struct audit_cap_data   cap;
+};
+
 struct audit_tree_refs {
         struct audit_tree_refs *next;
         struct audit_chunk *c[31];
@@ -1397,6 +1403,14 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
                         audit_log_cap(ab, "new_pe", &axs->new_pcap.effective);
                         break; }
 
+                case AUDIT_CAPSET: {
+                        struct audit_aux_data_capset *axs = (void *)aux;
+                        audit_log_format(ab, "pid=%d", axs->pid);
+                        audit_log_cap(ab, "cap_pi", &axs->cap.inheritable);
+                        audit_log_cap(ab, "cap_pp", &axs->cap.permitted);
+                        audit_log_cap(ab, "cap_pe", &axs->cap.effective);
+                        break; }
+
                 }
                 audit_log_end(ab);
         }
@@ -2570,6 +2584,40 @@ void __audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t *pP, kernel_
 }
 
 /**
+ * __audit_log_capset - store information about the arguments to the capset syscall
+ * @pid target pid of the capset call
+ * @eff effective cap set
+ * @inh inheritible cap set
+ * @perm permited cap set
+ *
+ * Record the aguments userspace sent to sys_capset for later printing by the
+ * audit system if applicable
+ */
+int __audit_log_capset(pid_t pid, kernel_cap_t *eff, kernel_cap_t *inh, kernel_cap_t *perm)
+{
+        struct audit_aux_data_capset *ax;
+        struct audit_context *context = current->audit_context;
+
+        if (likely(!audit_enabled || !context || context->dummy))
+                return 0;
+
+        ax = kmalloc(sizeof(*ax), GFP_KERNEL);
+        if (!ax)
+                return -ENOMEM;
+
+        ax->d.type = AUDIT_CAPSET;
+        ax->d.next = context->aux;
+        context->aux = (void *)ax;
+
+        ax->pid = pid;
+        ax->cap.effective = *eff;
+        ax->cap.inheritable = *eff;
+        ax->cap.permitted = *perm;
+
+        return 0;
+}
+
+/**
  * audit_core_dumps - record information about processes that end abnormally
  * @signr: signal value
  *
diff --git a/kernel/capability.c b/kernel/capability.c
index e13a68535ad5..19f9eda89975 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -7,6 +7,7 @@
  * 30 May 2002: Cleanup, Robert M. Love <rml@tech9.net>
  */
 
+#include <linux/audit.h>
 #include <linux/capability.h>
 #include <linux/mm.h>
 #include <linux/module.h>
@@ -468,6 +469,10 @@ asmlinkage long sys_capset(cap_user_header_t header, const cap_user_data_t data)
                 i++;
         }
 
+        ret = audit_log_capset(pid, &effective, &inheritable, &permitted);
+        if (ret)
+                return ret;
+
         if (pid && (pid != task_pid_vnr(current)))
                 ret = do_sys_capset_other_tasks(pid, &effective, &inheritable,
                                                 &permitted);