Hello Jinze.
The issue doesn't come from OpenSSL. It comes from at least two buffer overruns.
In aesEncrypt:
>
> ret = EVP_EncryptInit_ex(ctx, EVP_aes_128_ecb(), NULL, (const unsigned
> char*)key.c_str(), NULL);
You use key.c_str() to set the key. However, key here is "input":
>
> if (!aesEncrypt(content, "input", encrypted_content)) return -1;
key.c_str() returns a buffer of size 6: "input" plus the null-terminated byte.
However, EVP_aes_128_ecb expects a buffer of at least 16 bytes.
Therefore, this is UB: you don't control the 10 bytes after the buffer returned
by key.c_str().
Same with aesDecrypt:
> ret = EVP_DecryptInit_ex(ctx, EVP_aes_128_ecb(), NULL, (const unsigned
> char*)key.c_str(), NULL);
> if (!aesDecrypt(encrypted_content, "input", decrypted_content)) {
If you set "input" to "AAAAAAAAAAAAAAAA" ("A" x 16), it works.
The main issue here is that you use the wrong container for storing your key
materials and your buffers. You should use "std::vector<std::byte>" (or
"std::vector<uint8_t>") with std::vector::data().
Regards,
> On 12 Nov 2022, at 11:25, WuJinze via openssl-users
> <[email protected]> wrote:
>
> sorry for my mistake. I found that the gist url can not display well in mail
> and here is the url:
> https://gist.github.com/GoGim1/77c9bebec1cc71cea066515b4623a051
>
> WuJinze
> [email protected]
>
>
> ------------------ Original ------------------
> From: "WuJinze" <[email protected]>;
> Date: Sat, Nov 12, 2022 06:17 PM
> To: "openssl-users"<[email protected]>;Subject: OpenSSL AES
> Decryption fails randomly C++
>
> Dear OpenSSL Group,
> Greetings. I was working on writing simple aes encrypt/decrypt wrapper
> function in c++ and running into a strange problem. The minimal reproducible
> examples in gist seems working fine but when i uncomment lines 90-92, it will
> fail to decrypt randomly. Can someone help me to figure out what's wrong with
> the code?
> Here is my code: OpenSSL AES Decryption fails randomly C++ (github.com).
> OpenSSL version is OpenSSL 1.1.1f. G++ version is 9.4.0.
> Regards,
> Jinze
