[RFC][PATCH] audit: add ambient capabilities to CAPSET and BPRM_FCAPS records

[Richard Guy Briggs]

Capabilities were augmented to include ambient capabilities in v4.3
commit 58319057b784 ("capabilities: ambient capabilities").

Add ambient capabilities to the audit BPRM_FCAPS and CAPSET records.

The record contains fields "old_pp", "old_pi", "old_pe", "new_pp",
"new_pi", "new_pe" so in keeping with the previous record
normalizations, change the "new_*" variants to simply drop the "new_"
prefix.

A sample of the replaced BPRM_FCAPS record:
RAW: type=BPRM_FCAPS msg=audit(1491468034.252:237): fver=2 fp=0000000000200000 fi=0000000000000000 fe=1 old_pp=0000000000000000 old_pi=0000000000000000 old_pe=0000000000000000 old_pa=0000000000000000 pp=0000000000200000 pi=0000000000000000 pe=0000000000200000 pa=0000000000000000

INTERPRET: type=BPRM_FCAPS msg=audit(04/06/2017 04:40:34.252:237) : fver=2 fp=sys_admin fi=none fe=chown old_pp=none old_pi=none old_pe=none old_pa=none pp=sys_admin pi=none pe=sys_admin pa=none

A sample of the replaced CAPSET record:
RAW: type=CAPSET msg=audit(1491469502.371:242): pid=833 cap_pi=0000003fffffffff cap_pp=0000003fffffffff cap_pe=0000003fffffffff cap_pa=0000000000000000

INTERPRET: type=CAPSET msg=audit(04/06/2017 05:05:02.371:242) : pid=833
cap_pi=chown,dac_override,dac_read_search,fowner,fsetid,kill,setgid,setuid,setpcap,linux_immutable,net_bind_service,net_broadcast,net_admin,net_raw,ipc_lock,ipc_owner,sys_module,sys_rawio,sys_chroot,sys_ptrace,sys_pacct,sys_admin,sys_boot,sys_nice,sys_resource,sys_time,sys_tty_config,mknod,lease,audit_write,audit_control,setfcap,mac_override,mac_admin,syslog,wake_alarm,block_suspend,audit_read
cap_pp=chown,dac_override,dac_read_search,fowner,fsetid,kill,setgid,setuid,setpcap,linux_immutable,net_bind_service,net_broadcast,net_admin,net_raw,ipc_lock,ipc_owner,sys_module,sys_rawio,sys_chroot,sys_ptrace,sys_pacct,sys_admin,sys_boot,sys_nice,sys_resource,sys_time,sys_tty_config,mknod,lease,audit_write,audit_control,setfcap,mac_override,mac_admin,syslog,wake_alarm,block_suspend,audit_read
cap_pe=chown,dac_override,dac_read_search,fowner,fsetid,kill,setgid,setuid,setpcap,linux_immutable,net_bind_service,net_broadcast,net_admin,net_raw,ipc_lock,ipc_owner,sys_module,sys_rawio,sys_chroot,sys_ptrace,sys_pacct,sys_admin,sys_boot,sys_nice,sys_resource,sys_time,sys_tty_config,mknod,lease,audit_write,audit_control,setfcap,mac_override,mac_admin,syslog,wake_alarm,block_suspend,audit_read
cap_pa=none

See: https://github.com/linux-audit/audit-kernel/issues/40

Signed-off-by: Richard Guy Briggs <rgb at redhat.com>
---
 kernel/audit.h   |    1 +
 kernel/auditsc.c |   12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/audit.h b/kernel/audit.h
index 144b7eb..364b155 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -68,6 +68,7 @@ struct audit_cap_data {
 		unsigned int	fE;		/* effective bit of file cap */
 		kernel_cap_t	effective;	/* effective set of process */
 	};
+	kernel_cap_t		ambient;
 };
 
 /* When fs/namei.c:getname() is called, we store the pointer in name and bump
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4db32e8..ebfa93d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1260,6 +1260,7 @@ static void show_special(struct audit_context *context, int *call_panic)
 		audit_log_cap(ab, "cap_pi", &context->capset.cap.inheritable);
 		audit_log_cap(ab, "cap_pp", &context->capset.cap.permitted);
 		audit_log_cap(ab, "cap_pe", &context->capset.cap.effective);
+		audit_log_cap(ab, "cap_pa", &context->capset.cap.ambient);
 		break;
 	case AUDIT_MMAP:
 		audit_log_format(ab, "fd=%d flags=0x%x", context->mmap.fd,
@@ -1381,9 +1382,11 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
 			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);
+			audit_log_cap(ab, "old_pa", &axs->old_pcap.ambient);
+			audit_log_cap(ab, "pp", &axs->new_pcap.permitted);
+			audit_log_cap(ab, "pi", &axs->new_pcap.inheritable);
+			audit_log_cap(ab, "pe", &axs->new_pcap.effective);
+			audit_log_cap(ab, "pa", &axs->new_pcap.ambient);
 			break; }
 
 		}
@@ -2340,10 +2343,12 @@ int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
 	ax->old_pcap.permitted   = old->cap_permitted;
 	ax->old_pcap.inheritable = old->cap_inheritable;
 	ax->old_pcap.effective   = old->cap_effective;
+	ax->old_pcap.ambient     = old->cap_ambient;
 
 	ax->new_pcap.permitted   = new->cap_permitted;
 	ax->new_pcap.inheritable = new->cap_inheritable;
 	ax->new_pcap.effective   = new->cap_effective;
+	ax->new_pcap.ambient     = new->cap_ambient;
 	return 0;
 }
 
@@ -2362,6 +2367,7 @@ void __audit_log_capset(const struct cred *new, const struct cred *old)
 	context->capset.cap.effective   = new->cap_effective;
 	context->capset.cap.inheritable = new->cap_effective;
 	context->capset.cap.permitted   = new->cap_permitted;
+	context->capset.cap.ambient     = new->cap_ambient;
 	context->type = AUDIT_CAPSET;
 }
 
-- 
1.7.1

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