Unverified Commit 9194a995 authored by Johannes Schindelin's avatar Johannes Schindelin Committed by Daniel Stenberg
Browse files

SSL: Avoid magic allocation of SSL backend specific data 



Originally, my idea was to allocate the two structures (or more
precisely, the connectdata structure and the four SSL backend-specific
strucutres required for ssl[0..1] and proxy_ssl[0..1]) in one go, so
that they all could be free()d together.

However, getting the alignment right is tricky. Too tricky.

So let's just bite the bullet and allocate the SSL backend-specific
data separately.

As a consequence, we now have to be very careful to release the memory
allocated for the SSL backend-specific data whenever we release any
connectdata.

Signed-off-by: default avatarJohannes Schindelin <johannes.schindelin@gmx.de>

Closes #2119
parent 744ee583

lib/url.c

+24 −25
Original line number Diff line number Diff line
@@ -716,6 +716,10 @@ static void conn_free(struct connectdata *conn) 
  Curl_safefree(conn->unix_domain_socket);

#endif



#ifdef USE_SSL

  Curl_safefree(conn->ssl_extra);

#endif



  free(conn); /* free all the connection oriented data */

}
@@ -1793,38 +1797,27 @@ static void llist_dtor(void *user, void *element) 
 */

static struct connectdata *allocate_conn(struct Curl_easy *data)

{

  struct connectdata *conn;

  size_t connsize = sizeof(struct connectdata);



#ifdef USE_SSL

/* SSLBK_MAX_ALIGN: The max byte alignment a CPU would use */

#define SSLBK_MAX_ALIGN 32

  /* The SSL backend-specific data (ssl_backend_data) objects are allocated as

     part of connectdata at the end. To ensure suitable alignment we will

     assume a maximum of SSLBK_MAX_ALIGN for alignment. Since calloc returns a

     pointer suitably aligned for any variable this will ensure the

     ssl_backend_data array has proper alignment, even if that alignment turns

     out to be less than SSLBK_MAX_ALIGN. */

  size_t paddingsize = sizeof(struct connectdata) % SSLBK_MAX_ALIGN;

  size_t alignsize = paddingsize ? (SSLBK_MAX_ALIGN - paddingsize) : 0;

  size_t sslbksize = Curl_ssl->sizeof_ssl_backend_data;

  connsize += alignsize + (4 * sslbksize);

#endif



  conn = calloc(1, connsize);

  struct connectdata *conn = calloc(1, sizeof(struct connectdata));

  if(!conn)

    return NULL;



#ifdef USE_SSL

  /* Point to the ssl_backend_data objects at the end of connectdata.

  /* The SSL backend-specific data (ssl_backend_data) objects are allocated as

     a separate array to ensure suitable alignment.

     Note that these backend pointers can be swapped by vtls (eg ssl backend

     data becomes proxy backend data). */

  {

    char *end = (char *)conn + connsize;

    conn->ssl[0].backend = ((void *)(end - (4 * sslbksize)));

    conn->ssl[1].backend = ((void *)(end - (3 * sslbksize)));

    conn->proxy_ssl[0].backend = ((void *)(end - (2 * sslbksize)));

    conn->proxy_ssl[1].backend = ((void *)(end - (1 * sslbksize)));

    size_t sslsize = Curl_ssl->sizeof_ssl_backend_data;

    char *ssl = calloc(4, sslsize);

    if(!ssl) {

      free(conn);

      return NULL;

    }

    conn->ssl_extra = ssl;

    conn->ssl[0].backend = (void *)ssl;

    conn->ssl[1].backend = (void *)(ssl + sslsize);

    conn->proxy_ssl[0].backend = (void *)(ssl + 2 * sslsize);

    conn->proxy_ssl[1].backend = (void *)(ssl + 3 * sslsize);

  }

#endif
@@ -1953,6 +1946,9 @@ static struct connectdata *allocate_conn(struct Curl_easy *data) 


  free(conn->master_buffer);

  free(conn->localdev);

#ifdef USE_SSL

  free(conn->ssl_extra);

#endif

  free(conn);

  return NULL;

}
@@ -4438,6 +4434,9 @@ static CURLcode create_conn(struct Curl_easy *data, 
    conn_temp->inuse = TRUE; /* mark this as being in use so that no other

                                handle in a multi stack may nick it */

    reuse_conn(conn, conn_temp);

#ifdef USE_SSL

    free(conn->ssl_extra);

#endif

    free(conn);          /* we don't need this anymore */

    conn = conn_temp;

    *in_connect = conn;

lib/urldata.h

+3 −0
Original line number Diff line number Diff line
@@ -860,6 +860,9 @@ struct connectdata { 
#endif /* USE_RECV_BEFORE_SEND_WORKAROUND */

  struct ssl_connect_data ssl[2]; /* this is for ssl-stuff */

  struct ssl_connect_data proxy_ssl[2]; /* this is for proxy ssl-stuff */

#ifdef USE_SSL

  void *ssl_extra; /* separately allocated backend-specific data */

#endif

  struct ssl_primary_config ssl_config;

  struct ssl_primary_config proxy_ssl_config;

  bool tls_upgraded;