3 files changed, 116 insertions, 1 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 6272a395d43c..8cfb9feb2a05 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -99,6 +99,7 @@
 #define AUDIT_OBJ_PID           1318    /* ptrace target */
 #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_AVC               1400    /* SE Linux avc denial or grant */
 #define AUDIT_SELINUX_ERR       1401    /* Internal SE Linux Errors */
@@ -452,6 +453,7 @@ extern int __audit_mq_timedsend(mqd_t mqdes, size_t msg_len, unsigned int msg_pr
 extern int __audit_mq_timedreceive(mqd_t mqdes, size_t msg_len, unsigned int __user *u_msg_prio, const struct timespec __user *u_abs_timeout);
 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);
 
 static inline int audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
@@ -501,6 +503,29 @@ static inline int audit_mq_getsetattr(mqd_t mqdes, struct mq_attr *mqstat)
                 return __audit_mq_getsetattr(mqdes, mqstat);
         return 0;
 }
+
+/*
+ * ieieeeeee, an audit function without a return code!
+ *
+ * This function might fail!  I decided that it didn't matter.  We are too late
+ * to fail the syscall and the information isn't REQUIRED for any purpose.  It's
+ * just nice to have.  We should be able to look at past audit logs to figure
+ * out this process's current cap set along with the fcaps from the PATH record
+ * and use that to come up with the final set.  Yeah, its ugly, but all the info
+ * is still in the audit log.  So I'm not going to bother mentioning we failed
+ * if we couldn't allocate memory.
+ *
+ * If someone changes their mind they could create the aux record earlier and
+ * then search here and use that earlier allocation.  But I don't wanna.
+ *
+ * -Eric
+ */
+static inline void audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t *pP, kernel_cap_t *pE)
+{
+        if (unlikely(!audit_dummy_context()))
+                __audit_log_bprm_fcaps(bprm, pP, pE);
+}
+
 extern int audit_n_rules;
 extern int audit_signals;
 #else
@@ -532,6 +557,7 @@ extern int audit_signals;
 #define audit_mq_timedreceive(d,l,p,t) ({ 0; })
 #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_ptrace(t) ((void)0)
 #define audit_n_rules 0
 #define audit_signals 0
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index de7e9bcba9ae..3229cd4206f5 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -196,6 +196,14 @@ struct audit_aux_data_pids {
         int                     pid_count;
 };
 
+struct audit_aux_data_bprm_fcaps {
+        struct audit_aux_data   d;
+        struct audit_cap_data   fcap;
+        unsigned int            fcap_ver;
+        struct audit_cap_data   old_pcap;
+        struct audit_cap_data   new_pcap;
+};
+
 struct audit_tree_refs {
         struct audit_tree_refs *next;
         struct audit_chunk *c[31];
@@ -1375,6 +1383,20 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
                         audit_log_format(ab, "fd0=%d fd1=%d", axs->fd[0], axs->fd[1]);
                         break; }
 
+                case AUDIT_BPRM_FCAPS: {
+                        struct audit_aux_data_bprm_fcaps *axs = (void *)aux;
+                        audit_log_format(ab, "fver=%x", axs->fcap_ver);
+                        audit_log_cap(ab, "fp", &axs->fcap.permitted);
+                        audit_log_cap(ab, "fi", &axs->fcap.inheritable);
+                        audit_log_format(ab, " fe=%d", axs->fcap.fE);
+                        audit_log_cap(ab, "old_pp", &axs->old_pcap.permitted);
+                        audit_log_cap(ab, "old_pi", &axs->old_pcap.inheritable);
+                        audit_log_cap(ab, "old_pe", &axs->old_pcap.effective);
+                        audit_log_cap(ab, "new_pp", &axs->new_pcap.permitted);
+                        audit_log_cap(ab, "new_pi", &axs->new_pcap.inheritable);
+                        audit_log_cap(ab, "new_pe", &axs->new_pcap.effective);
+                        break; }
+
                 }
                 audit_log_end(ab);
         }
@@ -2502,6 +2524,52 @@ int __audit_signal_info(int sig, struct task_struct *t)
 }
 
 /**
+ * __audit_log_bprm_fcaps - store information about a loading bprm and relevant fcaps
+ * @bprm pointer to the bprm being processed
+ * @caps the caps read from the disk
+ *
+ * Simply check if the proc already has the caps given by the file and if not
+ * store the priv escalation info for later auditing at the end of the syscall
+ *
+ * this can fail and we don't care.  See the note in audit.h for
+ * audit_log_bprm_fcaps() for my explaination....
+ *
+ * -Eric
+ */
+void __audit_log_bprm_fcaps(struct linux_binprm *bprm, kernel_cap_t *pP, kernel_cap_t *pE)
+{
+        struct audit_aux_data_bprm_fcaps *ax;
+        struct audit_context *context = current->audit_context;
+        struct cpu_vfs_cap_data vcaps;
+        struct dentry *dentry;
+
+        ax = kmalloc(sizeof(*ax), GFP_KERNEL);
+        if (!ax)
+                return;
+
+        ax->d.type = AUDIT_BPRM_FCAPS;
+        ax->d.next = context->aux;
+        context->aux = (void *)ax;
+
+        dentry = dget(bprm->file->f_dentry);
+        get_vfs_caps_from_disk(dentry, &vcaps);
+        dput(dentry);
+
+        ax->fcap.permitted = vcaps.permitted;
+        ax->fcap.inheritable = vcaps.inheritable;
+        ax->fcap.fE = !!(vcaps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
+        ax->fcap_ver = (vcaps.magic_etc & VFS_CAP_REVISION_MASK) >> VFS_CAP_REVISION_SHIFT;
+
+        ax->old_pcap.permitted = *pP;
+        ax->old_pcap.inheritable = current->cap_inheritable;
+        ax->old_pcap.effective = *pE;
+
+        ax->new_pcap.permitted = current->cap_permitted;
+        ax->new_pcap.inheritable = current->cap_inheritable;
+        ax->new_pcap.effective = current->cap_effective;
+}
+
+/**
  * audit_core_dumps - record information about processes that end abnormally
  * @signr: signal value
  *
diff --git a/security/commoncap.c b/security/commoncap.c
index d7eff5797b91..d45393380997 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/capability.h>
+#include <linux/audit.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -376,6 +377,9 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
 
 void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
 {
+        kernel_cap_t pP = current->cap_permitted;
+        kernel_cap_t pE = current->cap_effective;
+
         if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
             !cap_issubset(bprm->cap_post_exec_permitted,
                           current->cap_permitted)) {
@@ -409,7 +413,24 @@ void cap_bprm_apply_creds (struct linux_binprm *bprm, int unsafe)
                         cap_clear(current->cap_effective);
         }
 
-        /* AUD: Audit candidate if current->cap_effective is set */
+        /*
+         * Audit candidate if current->cap_effective is set
+         *
+         * We do not bother to audit if 3 things are true:
+         *   1) cap_effective has all caps
+         *   2) we are root
+         *   3) root is supposed to have all caps (SECURE_NOROOT)
+         * Since this is just a normal root execing a process.
+         *
+         * Number 1 above might fail if you don't have a full bset, but I think
+         * that is interesting information to audit.
+         */
+        if (!cap_isclear(current->cap_effective)) {
+                if (!cap_issubset(CAP_FULL_SET, current->cap_effective) ||
+                    (bprm->e_uid != 0) || (current->uid != 0) ||
+                    issecure(SECURE_NOROOT))
+                        audit_log_bprm_fcaps(bprm, &pP, &pE);
+        }
 
         current->securebits &= ~issecure_mask(SECURE_KEEP_CAPS);
 }