git: 16f8f89c5c1f - main - cxgb: Avoid a read-after-free in get_packet() when cxgb_debug is on

[Mark Johnston]

The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=16f8f89c5c1f324a15a7e0607f03f041a230a572

commit 16f8f89c5c1f324a15a7e0607f03f041a230a572
Author:     Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-05-26 14:02:19 +0000
Commit:     Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-05-26 14:45:40 +0000

    cxgb: Avoid a read-after-free in get_packet() when cxgb_debug is on
    
    PR:             224927
    MFC after:      1 week
---
 sys/dev/cxgb/cxgb_sge.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/dev/cxgb/cxgb_sge.c b/sys/dev/cxgb/cxgb_sge.c
index f13d2f03180c..00b67880fcc8 100644
--- a/sys/dev/cxgb/cxgb_sge.c
+++ b/sys/dev/cxgb/cxgb_sge.c
@@ -2773,6 +2773,7 @@ get_packet(adapter_t *adap, unsigned int drop_thres, struct sge_qset *qs,
 		if (mh->mh_tail == NULL) {
 			log(LOG_ERR, "discarding intermediate descriptor entry\n");
 			m_freem(m);
+			m = NULL;
 			break;
 		}
 		mh->mh_tail->m_next = m;
@@ -2780,7 +2781,7 @@ get_packet(adapter_t *adap, unsigned int drop_thres, struct sge_qset *qs,
 		mh->mh_head->m_pkthdr.len += len;
 		break;
 	}
-	if (cxgb_debug)
+	if (cxgb_debug && m != NULL)
 		printf("len=%d pktlen=%d\n", m->m_len, m->m_pkthdr.len);
 done:
 	if (++fl->cidx == fl->size)