git: 647d3bf17cd9 - stable/12 - dma: exit if invoked with invalid (zero) argc

The branch stable/12 has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=647d3bf17cd907ded624dccf4fe4567924c4f399

commit 647d3bf17cd907ded624dccf4fe4567924c4f399
Author:     Ed Maste <emaste@FreeBSD.org>
AuthorDate: 2022-01-28 22:15:02 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2022-02-05 16:26:14 +0000

    dma: exit if invoked with invalid (zero) argc
    
    This was prompted by the recent pkexec vulnerability (CVE-2021-4034).
    This change is being made on general principle for setuid/setgid
    binaries and is not in response to an actual issue.
    
    Reviewed by:    kevans, markj (both earlier)
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D34087
    
    (cherry picked from commit 1c91aedf25bce879a8aced6439200e46601eb8a4)
---
 contrib/dma/dma.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/contrib/dma/dma.c b/contrib/dma/dma.c
index 72115ae2b55e..7cad25a214ee 100644
--- a/contrib/dma/dma.c
+++ b/contrib/dma/dma.c
@@ -428,6 +428,9 @@ main(int argc, char **argv)
 	int nodot = 0, showq = 0, queue_only = 0, newaliases = 0;
 	int recp_from_header = 0;
 
+	if (argc == 0)
+		errx(EX_OSERR, "invalid argc");
+
 	set_username();
 
 	/*