Commit 277740023def for kernel

commit 277740023def559a4a2ddc3e8e784ee37a0f16a9
Author: Xiang Mei <xmei5@asu.edu>
Date:   Sun May 10 23:21:38 2026 -0700

    net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot

    On the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is
    reserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt()
    populates V2 entries starting at index 1, so when no V1 device is
    selected slot 0 is left in its kzalloc()'ed state with ism_dev[0] ==
    NULL and ism_chid[0] == 0.

    smc_v2_determine_accepted_chid() then matches the peer's CHID against
    the array starting from index 0 using the CHID alone. A malicious
    peer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches
    the empty slot, ini->ism_selected becomes 0, and the subsequent
    ism_dev[0]->lgr_lock dereference in smc_conn_create() faults at
    offsetof(struct smcd_dev, lgr_lock) == 0x68:

      BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0
      Write of size 4 at addr 0000000000000068 by task exploit/144
      Call Trace:
       _raw_spin_lock_bh
       smc_conn_create (net/smc/smc_core.c:1997)
       __smc_connect (net/smc/af_smc.c:1447)
       smc_connect (net/smc/af_smc.c:1720)
       __sys_connect
       __x64_sys_connect
       do_syscall_64

    Require ism_dev[i] to be non-NULL before accepting a CHID match.

    Fixes: a7c9c5f4af7f ("net/smc: CLC accept / confirm V2")
    Reported-by: Weiming Shi <bestswngs@gmail.com>
    Assisted-by: Claude:claude-opus-4-7
    Signed-off-by: Xiang Mei <xmei5@asu.edu>
    Link: https://patch.msgid.link/20260511062138.2839584-1-xmei5@asu.edu
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index da28652f6810..dffbd529762d 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1400,7 +1400,8 @@ smc_v2_determine_accepted_chid(struct smc_clc_msg_accept_confirm *aclc,
 	int i;

 	for (i = 0; i < ini->ism_offered_cnt + 1; i++) {
-		if (ini->ism_chid[i] == ntohs(aclc->d1.chid)) {
+		if (ini->ism_dev[i] &&
+		    ini->ism_chid[i] == ntohs(aclc->d1.chid)) {
 			ini->ism_selected = i;
 			return 0;
 		}