diff options
| -rw-r--r-- | ChangeLog | 15 | ||||
| -rw-r--r-- | ext/openssl/ossl_cipher.c | 10 | ||||
| -rw-r--r-- | test/openssl/test_cipher.rb | 9 |
3 files changed, 33 insertions, 1 deletions
@@ -1,3 +1,18 @@ +Thu Jul 28 22:36:06 2011 Hiroshi Nakamura <nahi@ruby-lang.org> + + * ext/openssl/ossl_cipher.c (ossl_cipher_initialize): Avoid possible + SEGV from AES encryption/decryption. Processing data by + Cipher#update without initializing key (meaningless usage of Cipher + object since we don't offer a way to export a key) could cause SEGV. + + In OpenSSL, the EVP which has EVP_CIPH_RAND_KEY flag (such as DES3) + allows uninitialized key, but other EVPs (such as AES) does not + allow it. Calling EVP_CipherUpdate() without initializing key causes + SEGV so we set the data filled with "\0" as the key by default. See + #2768. + + * test/openssl/test_cipher.rb: test it. + Thu Jul 28 14:25:08 2011 NAKAMURA Usaku <usa@ruby-lang.org> * lib/rubygems/user_interaction.rb (Gem::StreamUI#tty?): typo. diff --git a/ext/openssl/ossl_cipher.c b/ext/openssl/ossl_cipher.c index ad6eab1e98..7a30641153 100644 --- a/ext/openssl/ossl_cipher.c +++ b/ext/openssl/ossl_cipher.c @@ -102,6 +102,7 @@ ossl_cipher_initialize(VALUE self, VALUE str) EVP_CIPHER_CTX *ctx; const EVP_CIPHER *cipher; char *name; + unsigned char key[EVP_MAX_KEY_LENGTH]; name = StringValuePtr(str); GetCipherInit(self, ctx); @@ -113,7 +114,14 @@ ossl_cipher_initialize(VALUE self, VALUE str) if (!(cipher = EVP_get_cipherbyname(name))) { ossl_raise(rb_eRuntimeError, "unsupported cipher algorithm (%s)", name); } - if (EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, -1) != 1) + /* + * The EVP which has EVP_CIPH_RAND_KEY flag (such as DES3) allows + * uninitialized key, but other EVPs (such as AES) does not allow it. + * Calling EVP_CipherUpdate() without initializing key causes SEGV so we + * set the data filled with "\0" as the key by default. + */ + memset(key, 0, EVP_MAX_KEY_LENGTH); + if (EVP_CipherInit_ex(ctx, cipher, NULL, key, NULL, -1) != 1) ossl_raise(eCipherError, NULL); return self; diff --git a/test/openssl/test_cipher.rb b/test/openssl/test_cipher.rb index 70c963bbb0..eb2f4fec57 100644 --- a/test/openssl/test_cipher.rb +++ b/test/openssl/test_cipher.rb @@ -90,6 +90,15 @@ class OpenSSL::TestCipher < Test::Unit::TestCase assert_equal(pt, c2.update(ct) + c2.final) } end + + def test_AES_crush + 500.times do + assert_nothing_raised("[Bug #2768]") do + # it caused OpenSSL SEGV by uninitialized key + OpenSSL::Cipher::AES128.new("ECB").update "." * 17 + end + end + end end end |