[ruby/openssl] cipher: fix buffer overflow in Cipher#update

OpenSSL::Cipher#update currently allocates the output buffer with size
(input data length)+(the block size of the cipher). This is insufficient
for the id-aes{128,192,256}-wrap-pad (AES keywrap with padding) ciphers.
They have a block size of 8 bytes, but the output may be up to 15 bytes
larger than the input.

Use (input data length)+EVP_MAX_BLOCK_LENGTH (== 32) as the output
buffer size, instead. OpenSSL doesn't provide a generic way to tell the
maximum required buffer size for ciphers, but this is large enough for
all algorithms implemented in current versions of OpenSSL.

Fixes: https://bugs.ruby-lang.org/issues/20236

https://github.com/ruby/openssl/commit/3035559f54

0 files changed, 0 insertions, 0 deletions