Use `tor_compress_supports_method()` before printing library versions.

This patch ensures that Tor checks if a given compression method is
supported before printing the version string when calling `tor
--library-versions`.

Additionally, we use the `tor_compress_supports_method()` to check if a
given version is supported for Tor's start-up version string, but here
we print "N/A" if a given compression method is unavailable.

See: https://bugs.torproject.org/21662

diff --git a/src/or/config.c b/src/or/config.c
index 3549a1d6086a73c037f23eb3ffdb86a1da94ecf7..a73f3970736acf9175cf3582fce11e6962d9184f 100644 (file)
--- a/src/or/config.c
+++ b/src/or/config.c
@@ -70,9 +70,6 @@
 #include "circuitmux_ewma.h"
 #include "circuitstats.h"
 #include "compress.h"
-#include "compress_lzma.h"
-#include "compress_zlib.h"
-#include "compress_zstd.h"
 #include "config.h"
 #include "connection.h"
 #include "connection_edge.h"
@@ -4952,15 +4949,21 @@ options_init_from_torrc(int argc, char **argv)
     printf("OpenSSL \t\t%-15s\t\t%s\n",
                       crypto_openssl_get_header_version_str(),
                       crypto_openssl_get_version_str());
-    printf("Zlib    \t\t%-15s\t\t%s\n",
-                      tor_zlib_get_header_version_str(),
-                      tor_zlib_get_version_str());
-    printf("Liblzma \t\t%-15s\t\t%s\n",
-                      tor_lzma_get_header_version_str(),
-                      tor_lzma_get_version_str());
-    printf("Libzstd \t\t%-15s\t\t%s\n",
-                      tor_zstd_get_header_version_str(),
-                      tor_zstd_get_version_str());
+    if (tor_compress_supports_method(ZLIB_METHOD)) {
+      printf("Zlib    \t\t%-15s\t\t%s\n",
+                        tor_compress_version_str(ZLIB_METHOD),
+                        tor_compress_header_version_str(ZLIB_METHOD));
+    }
+    if (tor_compress_supports_method(LZMA_METHOD)) {
+      printf("Liblzma \t\t%-15s\t\t%s\n",
+                        tor_compress_version_str(LZMA_METHOD),
+                        tor_compress_header_version_str(LZMA_METHOD));
+    }
+    if (tor_compress_supports_method(ZSTD_METHOD)) {
+      printf("Libzstd \t\t%-15s\t\t%s\n",
+                        tor_compress_version_str(ZSTD_METHOD),
+                        tor_compress_header_version_str(ZSTD_METHOD));
+    }
     //TODO: Hex versions?
     exit(0);
   }

diff --git a/src/or/main.c b/src/or/main.c
index f3a0d84aeaff72f8c31c711c324f36661a87db84..1ba6554d3e207126240f197f8b8d751c549fa5a9 100644 (file)
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -58,9 +58,7 @@
 #include "circuitlist.h"
 #include "circuituse.h"
 #include "command.h"
-#include "compress_lzma.h"
-#include "compress_zlib.h"
-#include "compress_zstd.h"
+#include "compress.h"
 #include "config.h"
 #include "confparse.h"
 #include "connection.h"
@@ -3005,9 +3003,12 @@ tor_init(int argc, char *argv[])
                get_uname(),
                tor_libevent_get_version_str(),
                crypto_openssl_get_version_str(),
-               tor_zlib_get_version_str(),
-               tor_lzma_get_version_str(),
-               tor_zstd_get_version_str());
+               tor_compress_supports_method(ZLIB_METHOD) ?
+                 tor_compress_version_str(ZLIB_METHOD) : "N/A",
+               tor_compress_supports_method(LZMA_METHOD) ?
+                 tor_compress_version_str(LZMA_METHOD) : "N/A",
+               tor_compress_supports_method(ZSTD_METHOD) ?
+                 tor_compress_version_str(ZSTD_METHOD) : "N/A");
 
     log_notice(LD_GENERAL, "Tor can't help you if you use it wrong! "
                "Learn how to be safe at "