git: 38c299fe8562 - stable/12 - ipdivert: check that PCB is still valid after taking INPCB_RLOCK.

[Andrey V. Elsukov]

The branch stable/12 has been updated by ae:

URL: https://cgit.FreeBSD.org/src/commit/?id=38c299fe856216d6ab38eb5e04d9ee4f8c22995d

commit 38c299fe856216d6ab38eb5e04d9ee4f8c22995d
Author:     Andrey V. Elsukov <ae at FreeBSD.org>
AuthorDate: 2021-03-30 09:31:09 +0000
Commit:     Andrey V. Elsukov <ae at FreeBSD.org>
CommitDate: 2021-04-06 06:50:55 +0000

    ipdivert: check that PCB is still valid after taking INPCB_RLOCK.
    
    We are inspecting PCBs of divert sockets under NET_EPOCH section,
    but PCB could be already detached and we should check INP_FREED flag
    when we took INP_RLOCK.
    
    PR:             254478
    Differential Revision:  https://reviews.freebsd.org/D29420
    
    (cherry picked from commit c80a4b76ceacc5aab322e7ac1407eea8c90cb3b1)
---
 sys/netinet/ip_divert.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/netinet/ip_divert.c b/sys/netinet/ip_divert.c
index bcde5416456b..81e70177e641 100644
--- a/sys/netinet/ip_divert.c
+++ b/sys/netinet/ip_divert.c
@@ -278,6 +278,10 @@ divert_packet(struct mbuf *m, int incoming)
 		/* XXX why does only one socket match? */
 		if (inp->inp_lport == nport) {
 			INP_RLOCK(inp);
+			if (__predict_false(inp->inp_flags2 & INP_FREED)) {
+				INP_RUNLOCK(inp);
+				continue;
+			}
 			sa = inp->inp_socket;
 			SOCKBUF_LOCK(&sa->so_rcv);
 			if (sbappendaddr_locked(&sa->so_rcv,