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 ac3730fdbf0b3e621ac5a98e9a0a2c12df0bfbc5..d1711d6a1b6ee73908b0eb46bbaa480a8e2a9dd7 100644 (file)
--- 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) {