NetworkManager/libnm-core/nm-crypto-nss.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Dan Williams <dcbw@redhat.com>
 * Copyright (C) 2007 - 2009 Red Hat, Inc.
 */

#include "nm-default.h"

#include "nm-crypto-impl.h"

NM_PRAGMA_WARNING_DISABLE("-Wstrict-prototypes")
#include <prinit.h>
#include <nss.h>
#include <pk11pub.h>
#include <pkcs11t.h>
#include <cert.h>
#include <prerror.h>
#include <p12.h>
#include <ciferfam.h>
#include <p12plcy.h>
NM_PRAGMA_WARNING_REENABLE

#include "nm-glib-aux/nm-secret-utils.h"
#include "nm-errors.h"

/*****************************************************************************/

static gboolean
_get_cipher_info(NMCryptoCipherType cipher,
                 CK_MECHANISM_TYPE *out_cipher_mech,
                 guint8 *           out_real_iv_len)
{
    static const CK_MECHANISM_TYPE cipher_mechs[] = {
        [NM_CRYPTO_CIPHER_DES_EDE3_CBC] = CKM_DES3_CBC_PAD,
        [NM_CRYPTO_CIPHER_DES_CBC]      = CKM_DES_CBC_PAD,
        [NM_CRYPTO_CIPHER_AES_128_CBC]  = CKM_AES_CBC_PAD,
        [NM_CRYPTO_CIPHER_AES_192_CBC]  = CKM_AES_CBC_PAD,
        [NM_CRYPTO_CIPHER_AES_256_CBC]  = CKM_AES_CBC_PAD,
    };

    g_return_val_if_fail(_NM_INT_NOT_NEGATIVE(cipher)
                             && (gsize) cipher < G_N_ELEMENTS(cipher_mechs),
                         FALSE);

    if (!cipher_mechs[cipher])
        return FALSE;

    NM_SET_OUT(out_cipher_mech, cipher_mechs[cipher]);
    NM_SET_OUT(out_real_iv_len, nm_crypto_cipher_get_info(cipher)->real_iv_len);
    return TRUE;
}

/*****************************************************************************/

gboolean
_nm_crypto_init(GError **error)
{
    static gboolean initialized = FALSE;
    SECStatus       ret;

    if (initialized)
        return TRUE;

    PR_Init(PR_USER_THREAD, PR_PRIORITY_NORMAL, 1);
    ret = NSS_NoDB_Init(NULL);
    if (ret != SECSuccess) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_FAILED,
                    _("Failed to initialize the crypto engine: %d."),
                    PR_GetError());
        PR_Cleanup();
        return FALSE;
    }

    SEC_PKCS12EnableCipher(PKCS12_RC4_40, 1);
    SEC_PKCS12EnableCipher(PKCS12_RC4_128, 1);
    SEC_PKCS12EnableCipher(PKCS12_RC2_CBC_40, 1);
    SEC_PKCS12EnableCipher(PKCS12_RC2_CBC_128, 1);
    SEC_PKCS12EnableCipher(PKCS12_DES_56, 1);
    SEC_PKCS12EnableCipher(PKCS12_DES_EDE3_168, 1);
    SEC_PKCS12SetPreferredCipher(PKCS12_DES_EDE3_168, 1);

    initialized = TRUE;
    return TRUE;
}

guint8 *
_nmtst_crypto_decrypt(NMCryptoCipherType cipher,
                      const guint8 *     data,
                      gsize              data_len,
                      const guint8 *     iv,
                      gsize              iv_len,
                      const guint8 *     key,
                      gsize              key_len,
                      gsize *            out_len,
                      GError **          error)
{
    CK_MECHANISM_TYPE                    cipher_mech;
    PK11SlotInfo *                       slot = NULL;
    SECItem                              key_item;
    PK11SymKey *                         sym_key   = NULL;
    SECItem *                            sec_param = NULL;
    PK11Context *                        ctx       = NULL;
    nm_auto_clear_secret_ptr NMSecretPtr output    = {0};
    SECStatus                            s;
    gboolean                             success       = FALSE;
    int                                  decrypted_len = 0;
    unsigned                             extra         = 0;
    unsigned                             pad_len       = 0;
    guint32                              i;
    guint8                               real_iv_len;

    if (!_get_cipher_info(cipher, &cipher_mech, &real_iv_len)) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_UNKNOWN_CIPHER,
                    _("Unsupported key cipher for decryption"));
        return NULL;
    }

    if (iv_len < real_iv_len) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_INVALID_DATA,
                    _("Invalid IV length (must be at least %u)."),
                    (guint) real_iv_len);
        return NULL;
    }

    if (!_nm_crypto_init(error))
        return NULL;

    slot = PK11_GetBestSlot(cipher_mech, NULL);
    if (!slot) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_FAILED,
                    _("Failed to initialize the decryption cipher slot."));
        goto out;
    }

    key_item.data = (unsigned char *) key;
    key_item.len  = key_len;
    sym_key = PK11_ImportSymKey(slot, cipher_mech, PK11_OriginUnwrap, CKA_DECRYPT, &key_item, NULL);
    if (!sym_key) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to set symmetric key for decryption."));
        goto out;
    }

    key_item.data = (unsigned char *) iv;
    key_item.len  = real_iv_len;
    sec_param     = PK11_ParamFromIV(cipher_mech, &key_item);
    if (!sec_param) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to set IV for decryption."));
        goto out;
    }

    ctx = PK11_CreateContextBySymKey(cipher_mech, CKA_DECRYPT, sym_key, sec_param);
    if (!ctx) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to initialize the decryption context."));
        goto out;
    }

    output.len = data_len;
    output.bin = g_malloc(data_len);

    s = PK11_CipherOp(ctx,
                      (unsigned char *) output.bin,
                      &decrypted_len,
                      output.len,
                      data,
                      data_len);
    if (s != SECSuccess) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to decrypt the private key: %d."),
                    PORT_GetError());
        goto out;
    }

    if (decrypted_len > data_len) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to decrypt the private key: decrypted data too large."));
        goto out;
    }

    s = PK11_DigestFinal(ctx,
                         (unsigned char *) &output.bin[decrypted_len],
                         &extra,
                         data_len - decrypted_len);
    if (s != SECSuccess) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to finalize decryption of the private key: %d."),
                    PORT_GetError());
        goto out;
    }

    decrypted_len += extra;
    pad_len = data_len - decrypted_len;

    /* Check if the padding at the end of the decrypted data is valid */
    if (pad_len == 0 || pad_len > real_iv_len) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Failed to decrypt the private key: unexpected padding length."));
        goto out;
    }

    /* Validate tail padding; last byte is the padding size, and all pad bytes
     * should contain the padding size.
     */
    for (i = pad_len; i > 0; i--) {
        if (output.bin[data_len - i] != pad_len) {
            g_set_error(error,
                        NM_CRYPTO_ERROR,
                        NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                        _("Failed to decrypt the private key."));
            goto out;
        }
    }

    success = TRUE;

out:
    if (ctx)
        PK11_DestroyContext(ctx, PR_TRUE);
    if (sym_key)
        PK11_FreeSymKey(sym_key);
    if (sec_param)
        SECITEM_FreeItem(sec_param, PR_TRUE);
    if (slot)
        PK11_FreeSlot(slot);

    if (!success)
        return NULL;

    if (decrypted_len < output.len)
        nm_explicit_bzero(&output.bin[decrypted_len], output.len - decrypted_len);
    *out_len = decrypted_len;
    return g_steal_pointer(&output.bin);
}

guint8 *
_nmtst_crypto_encrypt(NMCryptoCipherType cipher,
                      const guint8 *     data,
                      gsize              data_len,
                      const guint8 *     iv,
                      gsize              iv_len,
                      const guint8 *     key,
                      gsize              key_len,
                      gsize *            out_len,
                      GError **          error)
{
    SECStatus                            ret;
    CK_MECHANISM_TYPE                    cipher_mech = CKM_DES3_CBC_PAD;
    PK11SlotInfo *                       slot        = NULL;
    SECItem                              key_item = {.data = (unsigned char *) key, .len = key_len};
    SECItem                              iv_item  = {.data = (unsigned char *) iv, .len = iv_len};
    PK11SymKey *                         sym_key  = NULL;
    SECItem *                            sec_param     = NULL;
    PK11Context *                        ctx           = NULL;
    nm_auto_clear_secret_ptr NMSecretPtr padded_buf    = {0};
    nm_auto_clear_secret_ptr NMSecretPtr output        = {0};
    int                                  encrypted_len = 0, i;
    gboolean                             success       = FALSE;
    gsize                                pad_len;

    if (cipher == NM_CRYPTO_CIPHER_DES_CBC || !_get_cipher_info(cipher, &cipher_mech, NULL)) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_UNKNOWN_CIPHER,
                    _("Unsupported key cipher for encryption"));
        return NULL;
    }

    if (!_nm_crypto_init(error))
        return NULL;

    slot = PK11_GetBestSlot(cipher_mech, NULL);
    if (!slot) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_FAILED,
                    _("Failed to initialize the encryption cipher slot."));
        return NULL;
    }

    sym_key = PK11_ImportSymKey(slot, cipher_mech, PK11_OriginUnwrap, CKA_ENCRYPT, &key_item, NULL);
    if (!sym_key) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_ENCRYPTION_FAILED,
                    _("Failed to set symmetric key for encryption."));
        goto out;
    }

    sec_param = PK11_ParamFromIV(cipher_mech, &iv_item);
    if (!sec_param) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_ENCRYPTION_FAILED,
                    _("Failed to set IV for encryption."));
        goto out;
    }

    ctx = PK11_CreateContextBySymKey(cipher_mech, CKA_ENCRYPT, sym_key, sec_param);
    if (!ctx) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_ENCRYPTION_FAILED,
                    _("Failed to initialize the encryption context."));
        goto out;
    }

    /* If data->len % ivlen == 0, then we add another complete block
     * onto the end so that the decrypter knows there's padding.
     */
    pad_len = iv_len - (data_len % iv_len);

    padded_buf.len = data_len + pad_len;
    padded_buf.bin = g_malloc(padded_buf.len);

    memcpy(padded_buf.bin, data, data_len);
    for (i = 0; i < pad_len; i++)
        padded_buf.bin[data_len + i] = (guint8)(pad_len & 0xFF);

    output.len = padded_buf.len;
    output.bin = g_malloc(output.len);

    ret =
        PK11_CipherOp(ctx, output.bin, &encrypted_len, output.len, padded_buf.bin, padded_buf.len);
    if (ret != SECSuccess) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_ENCRYPTION_FAILED,
                    _("Failed to encrypt: %d."),
                    PORT_GetError());
        goto out;
    }

    if (encrypted_len != output.len) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_ENCRYPTION_FAILED,
                    _("Unexpected amount of data after encrypting."));
        goto out;
    }

    success = TRUE;

out:
    if (ctx)
        PK11_DestroyContext(ctx, PR_TRUE);
    if (sec_param)
        SECITEM_FreeItem(sec_param, PR_TRUE);
    if (sym_key)
        PK11_FreeSymKey(sym_key);
    if (slot)
        PK11_FreeSlot(slot);

    if (!success)
        return NULL;

    *out_len = output.len;
    return g_steal_pointer(&output.bin);
}

gboolean
_nm_crypto_verify_x509(const guint8 *data, gsize len, GError **error)
{
    CERTCertificate *cert;

    if (!_nm_crypto_init(error))
        return FALSE;

    /* Try DER/PEM first */
    cert = CERT_DecodeCertFromPackage((char *) data, len);
    if (!cert) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_INVALID_DATA,
                    _("Couldn't decode certificate: %d"),
                    PORT_GetError());
        return FALSE;
    }

    CERT_DestroyCertificate(cert);
    return TRUE;
}

gboolean
_nm_crypto_verify_pkcs12(const guint8 *data, gsize data_len, const char *password, GError **error)
{
    SEC_PKCS12DecoderContext *p12ctx = NULL;
    SECItem                   pw     = {0};
    PK11SlotInfo *            slot   = NULL;
    SECStatus                 s;
    gboolean                  success = FALSE;

    g_return_val_if_fail(!error || !*error, FALSE);

    if (!_nm_crypto_init(error))
        return FALSE;

    /* PKCS#12 passwords are apparently UCS2 BIG ENDIAN, and NSS doesn't do
     * any conversions for us.
     */
    if (password && *password) {
        nm_auto_clear_secret_ptr NMSecretPtr ucs2_password = {0};

        if (g_utf8_validate(password, -1, NULL)) {
            long ucs2_chars;

            ucs2_password.bin =
                (guint8 *) g_utf8_to_utf16(password, strlen(password), NULL, &ucs2_chars, NULL);

            /* cannot fail, because password is valid UTF-8*/
            nm_assert(ucs2_password.bin && ucs2_chars > 0);

            ucs2_password.len = ucs2_chars * 2;
        }

        if (!ucs2_password.bin || ucs2_password.len == 0) {
            g_set_error(error,
                        NM_CRYPTO_ERROR,
                        NM_CRYPTO_ERROR_INVALID_PASSWORD,
                        _("Password must be UTF-8"));
            return FALSE;
        }

        pw.data = PORT_ZAlloc(ucs2_password.len + 2);
        memcpy(pw.data, ucs2_password.bin, ucs2_password.len);
        pw.len = ucs2_password.len + 2;

#if __BYTE_ORDER == __LITTLE_ENDIAN
        {
            guint16 *p, *p_end;

            p_end = (guint16 *) &(((guint8 *) pw.data)[ucs2_password.len]);
            for (p = (guint16 *) pw.data; p < p_end; p++)
                *p = GUINT16_SWAP_LE_BE(*p);
        }
#endif
    }

    slot = PK11_GetInternalKeySlot();
    if (!slot) {
        g_set_error(error, NM_CRYPTO_ERROR, NM_CRYPTO_ERROR_FAILED, _("Couldn't initialize slot"));
        goto out;
    }

    p12ctx = SEC_PKCS12DecoderStart(&pw, slot, NULL, NULL, NULL, NULL, NULL, NULL);
    if (!p12ctx) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_FAILED,
                    _("Couldn't initialize PKCS#12 decoder: %d"),
                    PORT_GetError());
        goto out;
    }

    s = SEC_PKCS12DecoderUpdate(p12ctx, (guint8 *) data, data_len);
    if (s != SECSuccess) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_INVALID_DATA,
                    _("Couldn't decode PKCS#12 file: %d"),
                    PORT_GetError());
        goto out;
    }

    s = SEC_PKCS12DecoderVerify(p12ctx);
    if (s != SECSuccess) {
        g_set_error(error,
                    NM_CRYPTO_ERROR,
                    NM_CRYPTO_ERROR_DECRYPTION_FAILED,
                    _("Couldn't verify PKCS#12 file: %d"),
                    PORT_GetError());
        goto out;
    }

    success = TRUE;

out:
    if (p12ctx)
        SEC_PKCS12DecoderFinish(p12ctx);
    if (slot)
        PK11_FreeSlot(slot);

    if (pw.data)
        SECITEM_ZfreeItem(&pw, PR_FALSE);

    return success;
}

gboolean
_nm_crypto_verify_pkcs8(const guint8 *data,
                        gsize         data_len,
                        gboolean      is_encrypted,
                        const char *  password,
                        GError **     error)
{
    g_return_val_if_fail(data != NULL, FALSE);

    if (!_nm_crypto_init(error))
        return FALSE;

    /* NSS apparently doesn't do PKCS#8 natively, but you have to put the
     * PKCS#8 key into a PKCS#12 file and import that??  So until we figure
     * all that out, we can only assume the password is valid.
     */
    return TRUE;
}

gboolean
_nm_crypto_randomize(void *buffer, gsize buffer_len, GError **error)
{
    SECStatus s;

    if (!_nm_crypto_init(error))
        return FALSE;

    s = PK11_GenerateRandom(buffer, buffer_len);
    if (s != SECSuccess) {
        g_set_error_literal(error,
                            NM_CRYPTO_ERROR,
                            NM_CRYPTO_ERROR_FAILED,
                            _("Could not generate random data."));
        return FALSE;
    }
    return TRUE;
}