commit 1c77d8690caa1ad80b9d9581cac8eddae95e82d1 Author: Alexander Færøy ahf@torproject.org Date: Thu Apr 20 15:56:38 2017 +0200

Add function to check if a given compression method is supported.

This patch adds support for checking if a given `compress_method_t` is supported by the currently running Tor instance using `tor_compress_supports_method()`.

See: https://bugs.torproject.org/21662 --- src/common/compress.c | 19 +++++++++++++++++++ src/common/compress.h | 6 +++++- src/common/compress_lzma.c | 11 +++++++++++ src/common/compress_lzma.h | 3 +++ src/common/compress_zlib.c | 10 ++++++++++ src/common/compress_zlib.h | 3 +++ src/common/compress_zstd.c | 11 +++++++++++ src/common/compress_zstd.h | 3 +++ src/test/test_util.c | 15 +++++++++++++++ 9 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/src/common/compress.c b/src/common/compress.c index 52ff132..725dde5 100644 --- a/src/common/compress.c +++ b/src/common/compress.c @@ -154,6 +154,25 @@ detect_compression_method(const char *in, size_t in_len) } }

+/** Return 1 if a given <b>method</b> is supported; otherwise 0. */ +int +tor_compress_supports_method(compress_method_t method) +{ + switch (method) { + case GZIP_METHOD: + case ZLIB_METHOD: + return tor_zlib_method_supported(); + case LZMA_METHOD: + return tor_lzma_method_supported(); + case ZSTD_METHOD: + return tor_zstd_method_supported(); + case NO_METHOD: + case UNKNOWN_METHOD: + default: + return 0; + } +} + /** Return the approximate number of bytes allocated for all * supported compression schemas. */ size_t diff --git a/src/common/compress.h b/src/common/compress.h index 1fd4325..87306f5 100644 --- a/src/common/compress.h +++ b/src/common/compress.h @@ -13,7 +13,8 @@

/** Enumeration of what kind of compression to use. Only ZLIB_METHOD and * GZIP_METHOD is guaranteed to be supported by the compress/uncompress - * functions here. */ + * functions here. Call tor_compress_supports_method() to check if a given + * compression schema is supported by Tor. */ typedef enum { NO_METHOD=0, GZIP_METHOD=1, @@ -51,6 +52,9 @@ tor_compress_memory_level(compression_level_t level); int tor_compress_is_compression_bomb(size_t size_in, size_t size_out);

+int +tor_compress_supports_method(compress_method_t method); + size_t tor_compress_get_total_allocation(void);

diff --git a/src/common/compress_lzma.c b/src/common/compress_lzma.c index e1a7a66..c45cb5e 100644 --- a/src/common/compress_lzma.c +++ b/src/common/compress_lzma.c @@ -61,6 +61,17 @@ lzma_error_str(lzma_ret error) } #endif // HAVE_LZMA.

+/** Return 1 if LZMA compression is supported; otherwise 0. */ +int +tor_lzma_method_supported(void) +{ +#ifdef HAVE_LZMA + return 1; +#else + return 0; +#endif +} + /** Return a string representation of the version of the currently running * version of liblzma. */ const char * diff --git a/src/common/compress_lzma.h b/src/common/compress_lzma.h index 2cc3a00..801e22d 100644 --- a/src/common/compress_lzma.h +++ b/src/common/compress_lzma.h @@ -11,6 +11,9 @@ #ifndef TOR_COMPRESS_LZMA_H #define TOR_COMPRESS_LZMA_H

+int +tor_lzma_method_supported(void); + const char * tor_lzma_get_version_str(void);

diff --git a/src/common/compress_zlib.c b/src/common/compress_zlib.c index 2c9aba3..e1a68c2 100644 --- a/src/common/compress_zlib.c +++ b/src/common/compress_zlib.c @@ -64,6 +64,16 @@ method_bits(compress_method_t method, compression_level_t level) } }

+/** Return 1 if zlib/gzip compression is supported; otherwise 0. */ +int +tor_zlib_method_supported(void) +{ + /* We currently always support zlib/gzip, but we keep this function around in + * case we some day decide to deprecate zlib/gzip support. + */ + return 1; +} + /** Return a string representation of the version of the currently running * version of zlib. */ const char * diff --git a/src/common/compress_zlib.h b/src/common/compress_zlib.h index 0862678..0b1aad8 100644 --- a/src/common/compress_zlib.h +++ b/src/common/compress_zlib.h @@ -11,6 +11,9 @@ #ifndef TOR_COMPRESS_ZLIB_H #define TOR_COMPRESS_ZLIB_H

+int +tor_zlib_method_supported(void); + const char * tor_zlib_get_version_str(void);

diff --git a/src/common/compress_zstd.c b/src/common/compress_zstd.c index e2eb292..dca4dbd 100644 --- a/src/common/compress_zstd.c +++ b/src/common/compress_zstd.c @@ -26,6 +26,17 @@ /** Total number of bytes allocated for Zstandard state. */ static size_t total_zstd_allocation = 0;

+/** Return 1 if Zstandard compression is supported; otherwise 0. */ +int +tor_zstd_method_supported(void) +{ +#ifdef HAVE_ZSTD + return 1; +#else + return 0; +#endif +} + /** Return a string representation of the version of the currently running * version of libzstd. */ const char * diff --git a/src/common/compress_zstd.h b/src/common/compress_zstd.h index ec83ba9..b2297bd 100644 --- a/src/common/compress_zstd.h +++ b/src/common/compress_zstd.h @@ -11,6 +11,9 @@ #ifndef TOR_COMPRESS_ZSTD_H #define TOR_COMPRESS_ZSTD_H

+int +tor_zstd_method_supported(void); + const char * tor_zstd_get_version_str(void);

diff --git a/src/test/test_util.c b/src/test/test_util.c index 6a7db31..1e33de8 100644 --- a/src/test/test_util.c +++ b/src/test/test_util.c @@ -2252,6 +2252,9 @@ test_util_gzip(void *arg) tor_compress_state_t *state = NULL;

(void)arg; + tt_assert(tor_compress_supports_method(GZIP_METHOD)); + tt_assert(tor_compress_supports_method(ZLIB_METHOD)); + buf1 = tor_strdup("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ"); tt_assert(detect_compression_method(buf1, strlen(buf1)) == UNKNOWN_METHOD);

@@ -2414,6 +2417,8 @@ test_util_lzma(void *arg) tor_compress_state_t *state = NULL;

(void)arg; + tt_assert(tor_compress_supports_method(LZMA_METHOD)); + buf1 = tor_strdup("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ"); tt_assert(detect_compression_method(buf1, strlen(buf1)) == UNKNOWN_METHOD);

@@ -2507,6 +2512,10 @@ test_util_lzma(void *arg) tor_free(buf1); #else (void)arg; + tt_assert(! tor_compress_supports_method(LZMA_METHOD)); + + done: + ; #endif // HAVE_LZMA. }

@@ -2520,6 +2529,8 @@ test_util_zstd(void *arg) tor_compress_state_t *state = NULL;

(void)arg; + tt_assert(tor_compress_supports_method(ZSTD_METHOD)); + buf1 = tor_strdup("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAZAAAAAAAAAAAAAAAAAAAZ"); tt_assert(detect_compression_method(buf1, strlen(buf1)) == UNKNOWN_METHOD);

@@ -2613,6 +2624,10 @@ test_util_zstd(void *arg) tor_free(buf1); #else (void)arg; + tt_assert(! tor_compress_supports_method(ZSTD_METHOD)); + + done: + ; #endif // HAVE_ZSTD. }