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

1 files changed, 0 insertions, 97 deletions

diff --git a/usergen b/usergen
deleted file mode 100755
index eac072b..0000000
--- a/usergen
+++ /dev/null
@@ -1,97 +0,0 @@
-#! /bin/sh
-
-set -e
-
-usage()
-{
-    echo "$0 <dir>"
-}
-
-to_hex()
-{
-    od -An -t x1 | tr -d ' ' | tr -d '\n'
-}
-
-to_bin()
-{
-    sed -e 's,\([0-9a-f]\{2\}\),\\\\\\x\1,g' | xargs printf
-}
-
-mktemp_posix()
-{
-    m4 <<EOF
-mkstemp(${TMPDIR:-/tmp}/tmp.XXXXXX)
-EOF
-}
-
-if [ $# != 1 ]; then
-    usage >&2
-    exit 1
-fi
-
-DIR=$1
-
-echo Username: >&2
-IFS= read -r USER
-
-if printf '%s' "$USER" | grep -qe '[[:space:]]'
-then
-    echo Username cannot contain whitespaces >&2
-    exit 1
-fi
-
-DB="$DIR/db.json"
-
-if jq '.users[].name' "$DB" | grep -q $USER
-then
-    echo User $USER already in $DB >&2
-    exit 1
-fi
-
-TTYCFG=$(stty -g)
-trap "stty $TTYCFG" INT QUIT TERM EXIT
-stty -echo
-echo Password: >&2
-IFS= read -r PWD
-stty echo
-# Force newline
-echo
-
-echo "Quota, in MiB (leave empty for unlimited quota):" >&2
-read -r QUOTA
-QUOTA="${QUOTA:+"$(printf '%d' "$QUOTA")"}"
-
-PWD=$(printf '%s' "$PWD" | to_hex)
-SALT=$(openssl rand -hex 32)
-KEY=$(openssl rand -hex 32)
-PWD=$(printf '%s%s' "$SALT" "$PWD")
-
-ROUNDS=1000
-
-for i in $(seq $ROUNDS)
-do
-    printf "\r%d/$ROUNDS" $i >&2
-    PWD=$(printf '%s' "$PWD" | to_bin | openssl sha256 -r | cut -d' ' -f1)
-done
-
-echo >&2
-TMP=$(mktemp_posix)
-
-cleanup()
-{
-    rm -f $TMP
-}
-
-trap cleanup EXIT
-
-jq ".users += [
-{
-    \"name\": \"$USER\",
-    \"password\": \""$PWD"\",
-    \"salt\": \"$SALT\",
-    \"key\": \"$KEY\",
-    \"quota\": \"$QUOTA\"
-}]" "$DB" > $TMP
-
-mkdir -p "$DIR/user/$USER"
-mv $TMP "$DB"