git: 8ff4fc03e693 - main - traceroute6: fix capabilities for the rcv socket

[Michael Tuexen]

The branch main has been updated by tuexen:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=8ff4fc03e6933dd69f99a8f34f2aa0760300f248

commit 8ff4fc03e6933dd69f99a8f34f2aa0760300f248
Author:     Michael Tuexen <tue...@freebsd.org>
AuthorDate: 2022-10-04 21:34:58 +0000
Commit:     Michael Tuexen <tue...@freebsd.org>
CommitDate: 2022-10-04 21:40:29 +0000

    traceroute6: fix capabilities for the rcv socket
    
    On the receive socket, recvmsg() and poll()/select() is called.
    Therefore, CAP_EVENT is needed in addition to CAP_RECV..
    
    While there, check the socket for readbility before calling recvmsg().
    
    Reviewed by:            markj@
    MFC after:              3 days
    Sponsored by:           Netflix, Inc.
    Differential Revision:  https://reviews.freebsd.org/D36878
---
 usr.sbin/traceroute6/traceroute6.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/usr.sbin/traceroute6/traceroute6.c 
b/usr.sbin/traceroute6/traceroute6.c
index a071c084ad07..d887acf5ae53 100644
--- a/usr.sbin/traceroute6/traceroute6.c
+++ b/usr.sbin/traceroute6/traceroute6.c
@@ -937,7 +937,7 @@ main(int argc, char *argv[])
                    strerror(errno));
                exit(1);
        }
-       cap_rights_init(&rights, CAP_RECV);
+       cap_rights_init(&rights, CAP_RECV, CAP_EVENT);
        if (caph_rights_limit(rcvsock, &rights) < 0) {
                fprintf(stderr, "caph_rights_limit rcvsock: %s\n",
                    strerror(errno));
@@ -1039,7 +1039,8 @@ wait_for_reply(int sock, struct msghdr *mhdr)
        pfd[0].events = POLLIN;
        pfd[0].revents = 0;
 
-       if (poll(pfd, 1, waittime * 1000) > 0)
+       if (poll(pfd, 1, waittime * 1000) > 0 &&
+           pfd[0].revents & POLLIN)
                cc = recvmsg(rcvsock, mhdr, 0);
 
        return (cc);