File compression_methods_switch.patch of Package openssl.4936

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File compression_methods_switch.patch of Package openssl.4936

Index: openssl-1.0.2b/doc/ssl/SSL_COMP_add_compression_method.pod
===================================================================
--- openssl-1.0.2b.orig/doc/ssl/SSL_COMP_add_compression_method.pod	2015-06-11 20:11:49.353667505 +0200
+++ openssl-1.0.2b/doc/ssl/SSL_COMP_add_compression_method.pod	2015-06-11 20:11:51.183689314 +0200
@@ -47,6 +47,24 @@ of compression methods supported on a pe
 If enabled during compilation, the OpenSSL library will have the
 COMP_zlib() compression method available.
 
+And, there is an environment variable to switch the compression
+methods off and on. In default the compression is off to mitigate 
+the so called CRIME attack ( CVE-2012-4929). If you want to enable 
+compression again set OPENSSL_NO_DEFAULT_ZLIB to "no".
+
+The variable can be switched on and off at runtime; when this variable
+is set "no" compression is enabled, otherwise no, for example:
+
+in shell 'export OPENSSL_NO_DEFAULT_ZLIB=no'
+or in C to call
+int setenv(const char *name, const char *value, int overwrite); and
+int unsetenv(const char *name);
+
+Note: This reverts the behavior of the variable as it was before!
+
+And pay attention that this freaure is temporary, it maybe changed by
+the following updates.
+
 =head1 WARNINGS
 
 Once the identities of the compression methods for the TLS protocol have
Index: openssl-1.0.2b/ssl/ssl_ciph.c
===================================================================
--- openssl-1.0.2b.orig/ssl/ssl_ciph.c	2015-06-11 20:11:49.353667505 +0200
+++ openssl-1.0.2b/ssl/ssl_ciph.c	2015-06-11 20:11:51.183689314 +0200
@@ -478,10 +478,16 @@ static void load_builtin_compressions(vo
 
         if (ssl_comp_methods == NULL) {
             SSL_COMP *comp = NULL;
+            const char *nodefaultzlib;
 
             MemCheck_off();
             ssl_comp_methods = sk_SSL_COMP_new(sk_comp_cmp);
-            if (ssl_comp_methods != NULL) {
+		/* The default is "no" compression to avoid CRIME/BEAST */
+	nodefaultzlib = getenv("OPENSSL_NO_DEFAULT_ZLIB");
+	if (	ssl_comp_methods != NULL &&
+			nodefaultzlib &&
+			strncmp( nodefaultzlib, "no", 2) == 0)
+		{
                 comp = (SSL_COMP *)OPENSSL_malloc(sizeof(SSL_COMP));
                 if (comp != NULL) {
                     comp->method = COMP_zlib();

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File compression_methods_switch.patch of Package openssl.4936

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