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| author | Paul Kehrer <paul.l.kehrer@gmail.com> | 2017-07-20 10:45:54 +0200 |
|---|---|---|
| committer | Hynek Schlawack <hs@ox.cx> | 2017-07-20 10:45:54 +0200 |
| commit | 59d26251efd8a2a08abd9029018194430f7f25ca (patch) | |
| tree | 79a33413aaf11648d18f988e23d81456e52f4b26 /src/OpenSSL/crypto.py | |
| parent | 8102128e6ad83dcbb3567dd372cdd39c9a8fab44 (diff) | |
| download | pyopenssl-59d26251efd8a2a08abd9029018194430f7f25ca.tar.gz | |
(EC)DSA signature fix (#670)
* Write a test - signatures with EC keys (#609)
* Ask for signature length before allocating a buffer.
This fixes a potential heap buffer overflow that may happen when a signature
is longer than the private key, as with X9.62 ECDSA (#609).
* change approach to EVP_PKEY_size and add changelog
* add a small assert
Diffstat (limited to 'src/OpenSSL/crypto.py')
| -rw-r--r-- | src/OpenSSL/crypto.py | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/OpenSSL/crypto.py b/src/OpenSSL/crypto.py index 20cf183..4f7e4d8 100644 --- a/src/OpenSSL/crypto.py +++ b/src/OpenSSL/crypto.py @@ -2801,9 +2801,10 @@ def sign(pkey, data, digest): _lib.EVP_SignInit(md_ctx, digest_obj) _lib.EVP_SignUpdate(md_ctx, data, len(data)) - pkey_length = (PKey.bits(pkey) + 7) // 8 - signature_buffer = _ffi.new("unsigned char[]", pkey_length) - signature_length = _ffi.new("unsigned int*") + length = _lib.EVP_PKEY_size(pkey._pkey) + _openssl_assert(length > 0) + signature_buffer = _ffi.new("unsigned char[]", length) + signature_length = _ffi.new("unsigned int *") final_result = _lib.EVP_SignFinal( md_ctx, signature_buffer, signature_length, pkey._pkey) _openssl_assert(final_result == 1) |