From: Kamil Dudka <kdudka@redhat.com>
Date: Wed, 19 Jul 2017 16:02:26 +0000 (+0200)
Subject: nss: fix a possible use-after-free in SelectClientCert()
X-Git-Tag: curl-7_55_0~53
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=42a4cd4c78b3feb5ca07286479129116e125a730;p=thirdparty%2Fcurl.git

nss: fix a possible use-after-free in SelectClientCert()

... causing a SIGSEGV in showit() in case the handle used to initiate
the connection has already been freed.

This commit fixes a bug introduced in curl-7_19_5-204-g5f0cae803.

Reported-by: Rob Sanders
Bug: https://bugzilla.redhat.com/1436158
---

diff --git a/lib/vtls/nss.c b/lib/vtls/nss.c
index ac3730fdbf..d1711d6a1b 100644
--- a/lib/vtls/nss.c
+++ b/lib/vtls/nss.c
@@ -2184,6 +2184,10 @@ static ssize_t nss_send(struct connectdata *conn,  /* connection data */
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
   ssize_t rc;
 
+  /* The SelectClientCert() hook uses this for infof() and failf() but the
+     handle stored in nss_setup_connect() could have already been freed. */
+  connssl->data = conn->data;
+
   rc = PR_Send(connssl->handle, mem, (int)len, 0, PR_INTERVAL_NO_WAIT);
   if(rc < 0) {
     PRInt32 err = PR_GetError();
@@ -2217,6 +2221,10 @@ static ssize_t nss_recv(struct connectdata *conn,  /* connection data */
   struct ssl_connect_data *connssl = &conn->ssl[sockindex];
   ssize_t nread;
 
+  /* The SelectClientCert() hook uses this for infof() and failf() but the
+     handle stored in nss_setup_connect() could have already been freed. */
+  connssl->data = conn->data;
+
   nread = PR_Recv(connssl->handle, buf, (int)buffersize, 0,
                   PR_INTERVAL_NO_WAIT);
   if(nread < 0) {