From 10e42591ac72285736d5cc4ee5e7c2f68dbf1e4b Mon Sep 17 00:00:00 2001 From: Xavier Del Campo Romero Date: Wed, 8 Oct 2025 13:50:52 +0200 Subject: Replace OpenSSL with libsodium and argon2id The SHA256-based password hashing algorithm used by slcl(1) and usergen(1) is considered insecure against several kinds of attacks, including brute force attacks. [1] Therefore, a stronger password hashing algorithm based on the Argon2id key derivation function is now used by default. While OpenSSL does support Argon2id, it is only supported by very recent versions [2], which are still not packaged by most distributions as of the time of this writing. [3] As an alternative to OpenSSL, libsodium [4] had several benefits: - It provides easy-to-use functions for password hashing, base64 encoding/decoding and other cryptographic primitives used by slcl(1) and usergen(1). - It is packaged by most distributions [5], and most often only the patch version differs, which ensures good compatibility across distributions. Unfortunately, and as opposed to OpenSSL, libsodium does not come with command-line tools. Therefore, usergen(1) had to be rewritten in C. In order to maintain backwards compatiblity with existing databases, slcl(1) and usergen(1) shall support the insecure, SHA256-based password hashing algorithm. However, Argon2id shall now be the default choice for usergen(1). [1]: https://security.stackexchange.com/questions/195563/why-is-sha-256-not-good-for-passwords [2]: https://docs.openssl.org/3.3/man7/EVP_KDF-ARGON2/ [3]: https://repology.org/project/openssl/versions [4]: https://www.libsodium.org/ [5]: https://repology.org/project/libsodium/versions --- main.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'main.c') diff --git a/main.c b/main.c index 436c50d..1b70542 100644 --- a/main.c +++ b/main.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -522,13 +523,9 @@ static char *create_symlink(const char *const dir, const char *user) dynstr_init(&abs); dynstr_init(&rel); - if (RAND_bytes(buf, sizeof buf) != 1) - { - fprintf(stderr, "%s: RAND_bytes failed with %lu\n", - __func__, ERR_get_error()); - goto end; - } - else if (hex_encode(buf, dbuf, sizeof buf, sizeof dbuf)) + randombytes_buf(buf, sizeof buf); + + if (hex_encode(buf, dbuf, sizeof buf, sizeof dbuf)) { fprintf(stderr, "%s: hex_encode failed\n", __func__); goto end; @@ -2650,7 +2647,12 @@ int main(int argc, char *argv[]) dynstr_init(&ua.d); - if (parse_args(argc, argv, &dir, &port, &tmpdir, &ua.fifo) + if (sodium_init()) + { + fprintf(stderr, "%s: sodium_init failed\n", __func__); + goto end; + } + else if (parse_args(argc, argv, &dir, &port, &tmpdir, &ua.fifo) || init_dirs(dir) || ensure_style(dir) || !(ua.a = auth_alloc(dir)) -- cgit v1.2.3