git: 11417329c930 - stable/12 - tcp: Use local CC data only in the correct context

[Richard Scheffenegger]

The branch stable/12 has been updated by rscheff:

URL: https://cgit.FreeBSD.org/src/commit/?id=11417329c930adbed6297cd76f18c2b4ae7f5120

commit 11417329c930adbed6297cd76f18c2b4ae7f5120
Author:     Richard Scheffenegger <rscheff at FreeBSD.org>
AuthorDate: 2021-05-26 17:45:06 +0000
Commit:     Richard Scheffenegger <rscheff at FreeBSD.org>
CommitDate: 2021-05-31 06:58:34 +0000

    tcp: Use local CC data only in the correct context
    
    Most CC algos do use local data, and when calling
    newreno_cong_signal from there, the latter misinterprets
    the data as its own struct, leading to incorrect behavior.
    
    Reported by:  chengc_netapp.com
    Reviewed By:  chengc_netapp.com, tuexen, #transport
    MFC after:    3 days
    Sponsored By: NetApp, Inc.
    Differential Revision: https://reviews.freebsd.org/D30470
    
    (cherry picked from commit c358f1857f0c749ad166fb9e9bef04f4033f3a72)
---
 sys/netinet/cc/cc_newreno.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/sys/netinet/cc/cc_newreno.c b/sys/netinet/cc/cc_newreno.c
index 2379ae64e684..acc4fcfcda22 100644
--- a/sys/netinet/cc/cc_newreno.c
+++ b/sys/netinet/cc/cc_newreno.c
@@ -242,7 +242,12 @@ newreno_cong_signal(struct cc_var *ccv, uint32_t type)
 
 	cwin = CCV(ccv, snd_cwnd);
 	mss = tcp_maxseg(ccv->ccvc.tcp);
-	nreno = ccv->cc_data;
+	/*
+	 * Other TCP congestion controls use newreno_cong_signal(), but
+	 * with their own private cc_data. Make sure the cc_data is used
+	 * correctly.
+	 */
+	nreno = (CC_ALGO(ccv->ccvc.tcp) == &newreno_cc_algo) ? ccv->cc_data : NULL;
 	beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;
 	beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn;
 	if (V_cc_do_abe && type == CC_ECN)
@@ -332,6 +337,9 @@ newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf)
 	if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts))
 		return (EMSGSIZE);
 
+	if (CC_ALGO(ccv->ccvc.tcp) != &newreno_cc_algo)
+		return (ENOPROTOOPT);
+
 	nreno = ccv->cc_data;
 	opt = buf;