Any time fcaps or a setuid app under SECURE_NOROOT is used to result in a

non-zero pE we will crate a new audit record which contains the entire set
of known information about the executable in question, fP, fI, fE, fversion
and includes the process's pE, pI, pP.  Before and after the bprm capability
are applied.  This record type will only be emitted from execve syscalls.

an example of making ping use fcaps instead of setuid:

setcap "cat_net_raw+pe" /bin/ping

type=SYSCALL msg=audit(1225742021.015:236): arch=c000003e syscall=59 success=yes exit=0 a0=1457f30 a1=14606b0 a2=1463940 a3=321b770a70 items=2 ppid=2929 pid=2963 auid=0 uid=500 gid=500 euid=500 suid=500 fsuid=500 egid=500 sgid=500 fsgid=500 tty=pts0 ses=3 comm="ping" exe="/bin/ping" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1321] msg=audit(1225742021.015:236): fver=2 fp=0000000000002000 fi=0000000000000000 fe=1 old_pp=0000000000000000 old_pi=0000000000000000 old_pe=0000000000000000 new_pp=0000000000002000 new_pi=0000000000000000 new_pe=0000000000002000
type=EXECVE msg=audit(1225742021.015:236): argc=2 a0="ping" a1="127.0.0.1"
type=CWD msg=audit(1225742021.015:236):  cwd="/home/test"
type=PATH msg=audit(1225742021.015:236): item=0 name="/bin/ping" inode=49256 dev=fd:00 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ping_exec_t:s0 cap_fp=0000000000002000 cap_fe=1 cap_fver=2
type=PATH msg=audit(1225742021.015:236): item=1 name=(null) inode=507915 dev=fd:00 mode=0100755 ouid=0 ogid=0 rdev=00:00 obj=system_u:object_r:ld_so_t:s0

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

1 files changed, 68 insertions, 0 deletions

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
  *