Add BSM record conversion for a number of syscalls:

- thr_kill(2) and thr_exit(2) generally (no argument auditing here.
- A set of syscalls for the process descriptor family, specifically:
  pdfork(2), pdgetpid(2) and pdkill(2)

  For these syscalls, audit the file descriptor. In the case of pdfork(2)
  a pointer to an integer (file descriptor) is passed in as an argument.
  We audit the post initialized file descriptor (not the random garbage
  that would have been passed in). We will also audit the child process
  which was created from the fork operation (similar to what is done for
  the fork(2) syscall).

  pdkill(2) we audit the signal value and fd, and finally pdgetpid(2)
  just the file descriptor:

- Following is a sample of the produced audit trails:

  header,111,11,pdfork(2),0,Sat May 16 03:07:50 2020, + 394 msec
  argument,0,0x39d,child PID
  argument,2,0x2,flags
  argument,1,0x8,fd
  subject,root,root,0,root,0,924,0,0,0.0.0.0
  return,success,925

  header,79,11,pdgetpid(2),0,Sat May 16 03:07:50 2020, + 394 msec
  argument,1,0x8,fd
  subject,root,root,0,root,0,924,0,0,0.0.0.0
  return,success,0
  trailer,79

  header,135,11,pdkill(2),0,Sat May 16 03:07:50 2020, + 395 msec
  argument,1,0x8,fd
  argument,2,0xf,signal
  process_ex,root,root,0,root,0,925,0,0,0.0.0.0
  subject,root,root,0,root,0,924,0,0,0.0.0.0
  return,success,0
  trailer,135

MFC after:      1 week

2 files changed, 36 insertions, 0 deletions

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index f94b7d31791b..dbea55ccbd96 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -128,6 +128,7 @@ sys_pdfork(struct thread *td, struct pdfork_args *uap)
 	fr.fr_pidp = &pid;
 	fr.fr_pd_fd = &fd;
 	fr.fr_pd_flags = uap->flags;
+	AUDIT_ARG_FFLAGS(uap->flags);
 	/*
 	 * It is necessary to return fd by reference because 0 is a valid file
 	 * descriptor number, and the child needs to be able to distinguish
@@ -909,6 +910,7 @@ fork1(struct thread *td, struct fork_req *fr)
 		    fr->fr_pd_flags, fr->fr_pd_fcaps);
 		if (error != 0)
 			goto fail2;
+		AUDIT_ARG_FD(*fr->fr_pd_fd);
 	}
 
 	mem_charged = 0;
diff --git a/sys/security/audit/audit_bsm.c b/sys/security/audit/audit_bsm.c
index 7cc99de20086..3094509dbfdd 100644
--- a/sys/security/audit/audit_bsm.c
+++ b/sys/security/audit/audit_bsm.c
@@ -1317,6 +1317,38 @@ kaudit_to_bsm(struct kaudit_record *kar, struct au_record **pau)
 		UPATH1_VNODE1_TOKENS;
 		break;
 
+	case AUE_PDKILL:
+		if (ARG_IS_VALID(kar, ARG_FD)) {
+			tok = au_to_arg32(1, "fd", ar->ar_arg_fd);
+			kau_write(rec, tok);
+		}
+		if (ARG_IS_VALID(kar, ARG_SIGNUM)) {
+			tok = au_to_arg32(2, "signal", ar->ar_arg_signum);
+			kau_write(rec, tok);
+		}
+		PROCESS_PID_TOKENS(1);
+		break;
+	case AUE_PDFORK:
+		if (ARG_IS_VALID(kar, ARG_PID)) {
+			tok = au_to_arg32(0, "child PID", ar->ar_arg_pid);
+			kau_write(rec, tok);
+		}
+		if (ARG_IS_VALID(kar, ARG_FFLAGS)) {
+			tok = au_to_arg32(2, "flags", ar->ar_arg_fflags);
+			kau_write(rec, tok);
+		}
+		if (ARG_IS_VALID(kar, ARG_FD)) {
+			tok = au_to_arg32(1, "fd", ar->ar_arg_fd);
+			kau_write(rec, tok);
+		}
+		break;
+	case AUE_PDGETPID:
+		if (ARG_IS_VALID(kar, ARG_FD)) {
+			tok = au_to_arg32(1, "fd", ar->ar_arg_fd);
+			kau_write(rec, tok);
+		}
+		break;
+
 	case AUE_PROCCTL:
 		if (ARG_IS_VALID(kar, ARG_VALUE)) {
 			tok = au_to_arg32(1, "idtype", ar->ar_arg_value);
@@ -1747,6 +1779,8 @@ kaudit_to_bsm(struct kaudit_record *kar, struct au_record **pau)
 		break;
 
 	case AUE_THR_NEW:
+	case AUE_THR_KILL:
+	case AUE_THR_EXIT:
 		break;
 
 	case AUE_NULL: