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Diffstat (limited to 'ext/openssl/ossl_cipher.c')
-rw-r--r--ext/openssl/ossl_cipher.c22
1 files changed, 17 insertions, 5 deletions
diff --git a/ext/openssl/ossl_cipher.c b/ext/openssl/ossl_cipher.c
index 110610e1f9..6f74c925c0 100644
--- a/ext/openssl/ossl_cipher.c
+++ b/ext/openssl/ossl_cipher.c
@@ -386,11 +386,23 @@ ossl_cipher_update(int argc, VALUE *argv, VALUE self)
in = (unsigned char *)RSTRING_PTR(data);
in_len = RSTRING_LEN(data);
GetCipher(self, ctx);
- out_len = in_len+EVP_CIPHER_CTX_block_size(ctx);
- if (out_len <= 0) {
+
+ /*
+ * As of OpenSSL 3.2, there is no reliable way to determine the required
+ * output buffer size for arbitrary cipher modes.
+ * https://github.com/openssl/openssl/issues/22628
+ *
+ * in_len+block_size is usually sufficient, but AES key wrap with padding
+ * ciphers require in_len+15 even though they have a block size of 8 bytes.
+ *
+ * Using EVP_MAX_BLOCK_LENGTH (32) as a safe upper bound for ciphers
+ * currently implemented in OpenSSL, but this can change in the future.
+ */
+ if (in_len > LONG_MAX - EVP_MAX_BLOCK_LENGTH) {
ossl_raise(rb_eRangeError,
"data too big to make output buffer: %ld bytes", in_len);
}
+ out_len = in_len + EVP_MAX_BLOCK_LENGTH;
if (NIL_P(str)) {
str = rb_str_new(0, out_len);
@@ -401,7 +413,7 @@ ossl_cipher_update(int argc, VALUE *argv, VALUE self)
if (!ossl_cipher_update_long(ctx, (unsigned char *)RSTRING_PTR(str), &out_len, in, in_len))
ossl_raise(eCipherError, NULL);
- assert(out_len < RSTRING_LEN(str));
+ assert(out_len <= RSTRING_LEN(str));
rb_str_set_len(str, out_len);
return str;
@@ -442,8 +454,8 @@ ossl_cipher_final(VALUE self)
* call-seq:
* cipher.name -> string
*
- * Returns the name of the cipher which may differ slightly from the original
- * name provided.
+ * Returns the short name of the cipher which may differ slightly from the
+ * original name provided.
*/
static VALUE
ossl_cipher_name(VALUE self)