git: d33fba34ab19 - stable/13 - linux(4): Prevent an attempt to copy an uninitialized source address.

The branch stable/13 has been updated by dchagin:

URL: https://cgit.FreeBSD.org/src/commit/?id=d33fba34ab195d7d8bb5a8daabdad39ec7d9f4c4

commit d33fba34ab195d7d8bb5a8daabdad39ec7d9f4c4
Author:     Dmitry Chagin <dchagin@FreeBSD.org>
AuthorDate: 2022-04-11 20:29:45 +0000
Commit:     Dmitry Chagin <dchagin@FreeBSD.org>
CommitDate: 2022-06-17 19:33:50 +0000

    linux(4): Prevent an attempt to copy an uninitialized source address.
    
    PR:                     259380
    MFC after:              3 days
    
    (cherry picked from commit bb46e9b5107fd8763742f7e55b66ea2e574f5815)
---
 sys/compat/linux/linux_socket.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/sys/compat/linux/linux_socket.c b/sys/compat/linux/linux_socket.c
index 453a6621d9a7..935d07ecb7e0 100644
--- a/sys/compat/linux/linux_socket.c
+++ b/sys/compat/linux/linux_socket.c
@@ -1289,8 +1289,16 @@ linux_recvfrom(struct thread *td, struct linux_recvfrom_args *args)
 	if (error != 0)
 		goto out;
 
-	if (PTRIN(args->from) != NULL)
-		error = linux_copyout_sockaddr(sa, PTRIN(args->from), msg.msg_namelen);
+	/*
+	 * XXX. Seems that FreeBSD is different from Linux here. Linux
+	 * fill source address if underlying protocol provides it, while
+	 * FreeBSD fill it if underlying protocol is not connection-oriented.
+	 * So, kern_recvit() set msg.msg_namelen to 0 if protocol pr_flags
+	 * does not contains PR_ADDR flag.
+	 */
+	if (PTRIN(args->from) != NULL && msg.msg_namelen != 0)
+		error = linux_copyout_sockaddr(sa, PTRIN(args->from),
+		    msg.msg_namelen);
 
 	if (error == 0 && PTRIN(args->fromlen) != NULL)
 		error = copyout(&msg.msg_namelen, PTRIN(args->fromlen),