git: fc7993cf2d6d - main - rpcsec_tls: Avoid a socket reference underflow in rpctls_server()

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=fc7993cf2d6ddba9f94683565838bf8fabc0145c

commit fc7993cf2d6ddba9f94683565838bf8fabc0145c
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2026-06-15 15:52:24 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2026-06-15 15:54:30 +0000

    rpcsec_tls: Avoid a socket reference underflow in rpctls_server()
    
    The upcall_sockets tree owns a ref on any resident socket.  When a
    socket is removed after a TLS handshake failure, rpctls_rpc_failed()
    thus calls soclose().
    
    rpctls_server() does not acquire an extra ref to compensate for this.
    So, if the upcall fails, e.g., because rpc.tlsservd is not running,
    we'll call soclose() to drop the reference, but this effectively
    releases the xprt layer's reference.
    
    Fix the problem by explicitly acquiring a socket reference when adding
    a socket to the upcall tree.
    
    PR:             289734
    Reviewed by:    rmacklem, glebius
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:  https://reviews.freebsd.org/D57555
---
 sys/rpc/rpcsec_tls/rpctls_impl.c | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/sys/rpc/rpcsec_tls/rpctls_impl.c b/sys/rpc/rpcsec_tls/rpctls_impl.c
index e1b80217263f..621f6bcac3e4 100644
--- a/sys/rpc/rpcsec_tls/rpctls_impl.c
+++ b/sys/rpc/rpcsec_tls/rpctls_impl.c
@@ -190,7 +190,6 @@ sys_rpctls_syscall(struct thread *td, struct rpctls_syscall_args *uap)
 		CURVNET_RESTORE();
 		return (error);
 	}
-	soref(ups.so);
 	if (ups.server) {
 		/*
 		 * Once this file descriptor is associated
@@ -277,6 +276,7 @@ rpctls_connect(CLIENT *newclient, char *certname, struct socket *so,
 	if (stat != RPC_SUCCESS)
 		return (RPC_SYSTEMERROR);
 
+	soref(so);
 	mtx_lock(&rpctls_lock);
 	RB_INSERT(upsock_t, &upcall_sockets, &ups);
 	mtx_unlock(&rpctls_lock);
@@ -294,9 +294,16 @@ rpctls_connect(CLIENT *newclient, char *certname, struct socket *so,
 	stat = rpctlscd_connect_2(&arg, &res, rpctls_connect_handle);
 	if (stat == RPC_SUCCESS)
 		*reterr = res.reterr;
-	else
+	else {
 		rpctls_rpc_failed(&ups, so);
 
+		/*
+		 * The socket was closed, make sure the krpc code doesn't close
+		 * it a second time.
+		 */
+		CLNT_CONTROL(newclient, CLSET_TLS, &(int){RPCTLS_INHANDSHAKE});
+	}
+
 	/* Unblock reception. */
 	CLNT_CONTROL(newclient, CLSET_BLOCKRCV, &(int){0});
 
@@ -388,6 +395,7 @@ rpctls_server(SVCXPRT *xprt, uint32_t *flags, uid_t *uid, int *ngrps,
 	uint32_t *gidv;
 	int i;
 
+	soref(xprt->xp_socket);
 	mtx_lock(&rpctls_lock);
 	RB_INSERT(upsock_t, &upcall_sockets, &ups);
 	mtx_unlock(&rpctls_lock);
@@ -407,9 +415,18 @@ rpctls_server(SVCXPRT *xprt, uint32_t *flags, uid_t *uid, int *ngrps,
 			for (i = 0; i < *ngrps; i++)
 				*gidp++ = *gidv++;
 		}
-	} else
+	} else {
 		rpctls_rpc_failed(&ups, xprt->xp_socket);
 
+		/*
+		 * The socket was closed, make sure the krpc code doesn't close
+		 * it a second time.
+		 */
+		sx_xlock(&ups.xp->xp_lock);
+		ups.xp->xp_tls = RPCTLS_FLAGS_HANDSHFAIL;
+		sx_xunlock(&ups.xp->xp_lock);
+	}
+
 	mem_free(res.gid.gid_val, 0);
 
 #ifdef INVARIANTS