Fix some security bugs in the SVR4 emulator:

- Return NULL instead of returning memory outside of the stackgap
  in stackgap_alloc() (FreeBSD-SA-00:42.linux)
- Check for stackgap_alloc() returning NULL in svr4_emul_find(),
  and clean_pipe().
- Avoid integer overflow on large nfds argument in svr4_sys_poll()
- Reject negative nbytes argument in svr4_sys_getdents()
- Don't copy out past the end of the struct componentname
  pathname buffer in svr4_sys_resolvepath()
- Reject out-of-range signal numbers in svr4_sys_sigaction(),
  svr4_sys_signal(), and svr4_sys_kill().
- Don't malloc() user-specified lengths in show_ioc() and
  show_strbuf(), place arbitrary limits instead.
- Range-check lengths in si_listen(), ti_getinfo(), ti_bind(),
  svr4_do_putmsg(), svr4_do_getmsg(), svr4_stream_ti_ioctl().

Some fixes obtain from OpenBSD.

1 files changed, 4 insertions, 2 deletions

diff --git a/sys/compat/svr4/svr4_sysvec.c b/sys/compat/svr4/svr4_sysvec.c
index c488da2..61efd49 100644
--- a/sys/compat/svr4/svr4_sysvec.c
+++ b/sys/compat/svr4/svr4_sysvec.c
@@ -364,8 +364,10 @@ svr4_emul_find(td, sgp, prefix, path, pbuf, cflag)
 		*pbuf = buf;
 	else {
 		sz = &ptr[len] - buf;
-		*pbuf = stackgap_alloc(sgp, sz + 1);
-		error = copyout(buf, *pbuf, sz);
+		if ((*pbuf = stackgap_alloc(sgp, sz + 1)) != NULL)
+			error = copyout(buf, *pbuf, sz);
+		else
+			error = ENAMETOOLONG;
 		free(buf, M_TEMP);
 	}