Merge commit '8b09d917'

* commit '8b09d917':
  tls: Add options for verifying the peer certificate

Conflicts:
	doc/protocols.texi
	libavformat/tls.c
	libavformat/version.h

See: b2460858
See: 973a758fMerged-by: Michael Niedermayer <michaelni@gmx.at>

doc/protocols.texi

@@ -853,30 +853,45 @@ ffplay tcp://@var{hostname}:@var{port}
 
 @section tls
 
-Transport Layer Security/Secure Sockets Layer
+Transport Layer Security (TLS) / Secure Sockets Layer (SSL)
 
 The required syntax for a TLS/SSL url is:
 @example
 tls://@var{hostname}:@var{port}[?@var{options}]
 @end example
 
+The following parameters can be set via command line options
+(or in code via @code{AVOption}s):
+
 @table @option
 
+@item ca_file, cafile=@var{filename}
+A file containing certificate authority (CA) root certificates to treat
+as trusted. If the linked TLS library contains a default this might not
+need to be specified for verification to work, but not all libraries and
+setups have defaults built in.
+The file must be in OpenSSL PEM format.
+
+@item tls_verify=@var{1|0}
+If enabled, try to verify the peer that we are communicating with.
+Note, if using OpenSSL, this currently only makes sure that the
+peer certificate is signed by one of the root certificates in the CA
+database, but it does not validate that the certificate actually
+matches the host name we are trying to connect to. (With GnuTLS,
+the host name is validated as well.)
+
+This is disabled by default since it requires a CA database to be
+provided by the caller in many cases.
+
 @item listen
 Act as a server, listening for an incoming connection.
 
-@item cafile=@var{filename}
-Certificate authority file. The file must be in OpenSSL PEM format.
-
 @item cert=@var{filename}
 Certificate file. The file must be in OpenSSL PEM format.
 
 @item key=@var{filename}
 Private key file.
 
-@item verify=@var{0|1}
-Verify the peer's certificate.
-
 @end table
 
 Example command lines:

libavformat/tls.c

@@ -22,9 +22,11 @@
 #include "avformat.h"
 #include "url.h"
 #include "libavutil/avstring.h"
+#include "libavutil/opt.h"
 #include "libavutil/parseutils.h"
 #if CONFIG_GNUTLS
 #include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
 #define TLS_read(c, buf, size)  gnutls_record_recv(c->session, buf, size)
 #define TLS_write(c, buf, size) gnutls_record_send(c->session, buf, size)
 #define TLS_shutdown(c)         gnutls_bye(c->session, GNUTLS_SHUT_RDWR)
@@ -66,8 +68,27 @@ typedef struct {
     SSL *ssl;
 #endif
     int fd;
+    char *ca_file;
+    int verify;
 } TLSContext;
 
+#define OFFSET(x) offsetof(TLSContext, x)
+#define D AV_OPT_FLAG_DECODING_PARAM
+#define E AV_OPT_FLAG_ENCODING_PARAM
+static const AVOption options[] = {
+    {"ca_file",    "Certificate Authority database file", OFFSET(ca_file),   AV_OPT_TYPE_STRING, .flags = D|E },
+    {"cafile",     "Certificate Authority database file", OFFSET(ca_file),   AV_OPT_TYPE_STRING, .flags = D|E },
+    {"tls_verify", "Verify the peer certificate",         OFFSET(verify),    AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, .flags = D|E },
+    { NULL }
+};
+
+static const AVClass tls_class = {
+    .class_name = "tls",
+    .item_name  = av_default_item_name,
+    .option     = options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
 static int do_tls_poll(URLContext *h, int ret)
 {
     TLSContext *c = h->priv_data;
@@ -115,7 +136,7 @@ static void set_options(URLContext *h, const char *uri)
 {
     TLSContext *c = h->priv_data;
     char buf[1024], key[1024];
-    int has_cert, has_key, verify = 0;
+    int has_cert, has_key;
 #if CONFIG_GNUTLS
     int ret;
 #endif
@@ -123,22 +144,14 @@ static void set_options(URLContext *h, const char *uri)
     if (!p)
         return;
 
-    if (av_find_info_tag(buf, sizeof(buf), "cafile", p)) {
-#if CONFIG_GNUTLS
-        ret = gnutls_certificate_set_x509_trust_file(c->cred, buf, GNUTLS_X509_FMT_PEM);
-        if (ret < 0)
-            av_log(h, AV_LOG_ERROR, "%s\n", gnutls_strerror(ret));
-#elif CONFIG_OPENSSL
-        if (!SSL_CTX_load_verify_locations(c->ctx, buf, NULL))
-            av_log(h, AV_LOG_ERROR, "SSL_CTX_load_verify_locations %s\n", ERR_error_string(ERR_get_error(), NULL));
-#endif
-    }
+    if (!c->ca_file && av_find_info_tag(buf, sizeof(buf), "cafile", p))
+        c->ca_file = av_strdup(buf);
 
-    if (av_find_info_tag(buf, sizeof(buf), "verify", p)) {
+    if (!c->verify && av_find_info_tag(buf, sizeof(buf), "verify", p)) {
         char *endptr = NULL;
-        verify = strtol(buf, &endptr, 10);
+        c->verify = strtol(buf, &endptr, 10);
         if (buf == endptr)
-            verify = 1;
+            c->verify = 1;
     }
 
     has_cert = av_find_info_tag(buf, sizeof(buf), "cert", p);
@@ -151,14 +164,11 @@ static void set_options(URLContext *h, const char *uri)
     } else if (has_cert ^ has_key) {
         av_log(h, AV_LOG_ERROR, "cert and key required\n");
     }
-    gnutls_certificate_set_verify_flags(c->cred, verify);
 #elif CONFIG_OPENSSL
     if (has_cert && !SSL_CTX_use_certificate_chain_file(c->ctx, buf))
         av_log(h, AV_LOG_ERROR, "SSL_CTX_use_certificate_chain_file %s\n", ERR_error_string(ERR_get_error(), NULL));
     if (has_key && !SSL_CTX_use_PrivateKey_file(c->ctx, key, SSL_FILETYPE_PEM))
         av_log(h, AV_LOG_ERROR, "SSL_CTX_use_PrivateKey_file %s\n", ERR_error_string(ERR_get_error(), NULL));
-    if (verify)
-        SSL_CTX_set_verify(c->ctx, SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT, 0);
 #endif
 }
 
@@ -215,6 +225,17 @@ static int tls_open(URLContext *h, const char *uri, int flags)
         gnutls_server_name_set(c->session, GNUTLS_NAME_DNS, host, strlen(host));
     gnutls_certificate_allocate_credentials(&c->cred);
     set_options(h, uri);
+    if (c->ca_file) {
+        ret = gnutls_certificate_set_x509_trust_file(c->cred, c->ca_file, GNUTLS_X509_FMT_PEM);
+        if (ret < 0)
+            av_log(h, AV_LOG_ERROR, "%s\n", gnutls_strerror(ret));
+    }
+#if GNUTLS_VERSION_MAJOR >= 3
+    else
+        gnutls_certificate_set_x509_system_trust(c->cred);
+#endif
+    gnutls_certificate_set_verify_flags(c->cred, c->verify ?
+                                        GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT : 0);
     gnutls_credentials_set(c->session, GNUTLS_CRD_CERTIFICATE, c->cred);
     gnutls_transport_set_ptr(c->session, (gnutls_transport_ptr_t)
                                          (intptr_t) c->fd);
@@ -226,6 +247,38 @@ static int tls_open(URLContext *h, const char *uri, int flags)
         if ((ret = do_tls_poll(h, ret)) < 0)
             goto fail;
     }
+    if (c->verify) {
+        unsigned int status, cert_list_size;
+        gnutls_x509_crt_t cert;
+        const gnutls_datum_t *cert_list;
+        if ((ret = gnutls_certificate_verify_peers2(c->session, &status)) < 0) {
+            av_log(h, AV_LOG_ERROR, "Unable to verify peer certificate: %s\n",
+                                    gnutls_strerror(ret));
+            ret = AVERROR(EIO);
+            goto fail;
+        }
+        if (status & GNUTLS_CERT_INVALID) {
+            av_log(h, AV_LOG_ERROR, "Peer certificate failed verification\n");
+            ret = AVERROR(EIO);
+            goto fail;
+        }
+        if (gnutls_certificate_type_get(c->session) != GNUTLS_CRT_X509) {
+            av_log(h, AV_LOG_ERROR, "Unsupported certificate type\n");
+            ret = AVERROR(EIO);
+            goto fail;
+        }
+        gnutls_x509_crt_init(&cert);
+        cert_list = gnutls_certificate_get_peers(c->session, &cert_list_size);
+        gnutls_x509_crt_import(cert, cert_list, GNUTLS_X509_FMT_DER);
+        ret = gnutls_x509_crt_check_hostname(cert, host);
+        gnutls_x509_crt_deinit(cert);
+        if (!ret) {
+            av_log(h, AV_LOG_ERROR,
+                   "The certificate's owner does not match hostname %s\n", host);
+            ret = AVERROR(EIO);
+            goto fail;
+        }
+    }
 #elif CONFIG_OPENSSL
     c->ctx = SSL_CTX_new(server ? TLSv1_server_method() : TLSv1_client_method());
     if (!c->ctx) {
@@ -234,6 +287,14 @@ static int tls_open(URLContext *h, const char *uri, int flags)
         goto fail;
     }
     set_options(h, uri);
+    if (c->ca_file) {
+        if (!SSL_CTX_load_verify_locations(c->ctx, c->ca_file, NULL))
+            av_log(h, AV_LOG_ERROR, "SSL_CTX_load_verify_locations %s\n", ERR_error_string(ERR_get_error(), NULL));
+    }
+    // Note, this doesn't check that the peer certificate actually matches
+    // the requested hostname.
+    if (c->verify)
+        SSL_CTX_set_verify(c->ctx, SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL);
     c->ssl = SSL_new(c->ctx);
     if (!c->ssl) {
         av_log(h, AV_LOG_ERROR, "%s\n", ERR_error_string(ERR_get_error(), NULL));
@@ -313,4 +374,5 @@ URLProtocol ff_tls_protocol = {
     .url_close      = tls_close,
     .priv_data_size = sizeof(TLSContext),
     .flags          = URL_PROTOCOL_FLAG_NETWORK,
+    .priv_data_class = &tls_class,
 };

libavformat/version.h

@@ -31,7 +31,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR 55
 #define LIBAVFORMAT_VERSION_MINOR 18
-#define LIBAVFORMAT_VERSION_MICRO 102
+#define LIBAVFORMAT_VERSION_MICRO 103
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \