/src/openssl/providers/implementations/ciphers/ciphercommon_gcm.c

Source
/*
 * Copyright 2019-2026 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

/* Dispatch functions for gcm mode */

#include <openssl/rand.h>
#include <openssl/proverr.h>
#include "prov/ciphercommon.h"
#include "prov/ciphercommon_gcm.h"
#include "prov/providercommon.h"
#include "prov/provider_ctx.h"
#include "fips/fipsindicator.h"

#include "providers/implementations/ciphers/ciphercommon_gcm.inc"

static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len);
static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
    size_t len);
static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
    const unsigned char *in, size_t len);
static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
    size_t *padlen, const unsigned char *in,
    size_t len);
static int on_preupdate_generate_iv(PROV_GCM_CTX *ctx);

#ifdef FIPS_MODULE
static int gcm_fips_taglen_approved(size_t taglen)
{
    return taglen == UNINITIALISED_SIZET || taglen == 4 || taglen == 8
        || (taglen >= 12 && taglen <= GCM_TAG_MAX_SIZE);
}
#endif

/*
 * Called from EVP_CipherInit when there is currently no context via
 * the new_ctx() function
 */
void ossl_gcm_initctx(void *provctx, PROV_GCM_CTX *ctx, size_t keybits,
    const PROV_GCM_HW *hw)
{
    ctx->pad = 1;
    ctx->mode = EVP_CIPH_GCM_MODE;
    ctx->taglen = UNINITIALISED_SIZET;
    ctx->tls_aad_len = UNINITIALISED_SIZET;
    ctx->ivlen = (EVP_GCM_TLS_FIXED_IV_LEN + EVP_GCM_TLS_EXPLICIT_IV_LEN);
    ctx->keylen = keybits / 8;
    ctx->hw = hw;
    ctx->libctx = PROV_LIBCTX_OF(provctx);
}

/*
 * Called by EVP_CipherInit via the _einit and _dinit functions
 */
static int gcm_init(void *vctx, const unsigned char *key, size_t keylen,
    const unsigned char *iv, size_t ivlen,
    const OSSL_PARAM params[], int enc)
{
    PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;

    if (!ossl_prov_is_running())
        return 0;

    ctx->enc = enc;

    if (iv != NULL) {
        if (ivlen == 0 || ivlen > sizeof(ctx->iv)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
            return 0;
        }
        ctx->iv_gen_rand = 0;
        ctx->ivlen = ivlen;
        memcpy(ctx->iv, iv, ivlen);
        ctx->iv_state = IV_STATE_BUFFERED;
    }

    if (key != NULL) {
        if (keylen != ctx->keylen) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
            return 0;
        }
        if (!ctx->hw->setkey(ctx, key, ctx->keylen))
            return 0;
        ctx->tls_enc_records = 0;
    }
    return ossl_gcm_set_ctx_params(ctx, params);
}

int ossl_gcm_einit(void *vctx, const unsigned char *key, size_t keylen,
    const unsigned char *iv, size_t ivlen,
    const OSSL_PARAM params[])
{
    return gcm_init(vctx, key, keylen, iv, ivlen, params, 1);
}

int ossl_gcm_dinit(void *vctx, const unsigned char *key, size_t keylen,
    const unsigned char *iv, size_t ivlen,
    const OSSL_PARAM params[])
{
    return gcm_init(vctx, key, keylen, iv, ivlen, params, 0);
}

/* increment counter (64-bit int) by 1 */
static void ctr64_inc(unsigned char *counter)
{
    int n = 8;
    unsigned char c;

    do {
        --n;
        c = counter[n];
        ++c;
        counter[n] = c;
        if (c > 0)
            return;
    } while (n > 0);
}

static int getivgen(PROV_GCM_CTX *ctx, unsigned char *out, size_t olen)
{
    if (!ctx->iv_gen
        || !ctx->key_set
        || !ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
        return 0;
    if (olen == 0 || olen > ctx->ivlen)
        olen = ctx->ivlen;
    memcpy(out, ctx->iv + ctx->ivlen - olen, olen);
    /*
     * Invocation field will be at least 8 bytes in size and so no need
     * to check wrap around or increment more than last 8 bytes.
     */
    ctr64_inc(ctx->iv + ctx->ivlen - 8);
    ctx->iv_state = IV_STATE_COPIED;
    return 1;
}

static int setivinv(PROV_GCM_CTX *ctx, unsigned char *in, size_t inl)
{
    if (!ctx->iv_gen
        || !ctx->key_set
        || ctx->enc)
        return 0;

    memcpy(ctx->iv + ctx->ivlen - inl, in, inl);
    if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
        return 0;
    ctx->iv_state = IV_STATE_COPIED;
    return 1;
}

const OSSL_PARAM *ossl_gcm_gettable_ctx_params(
    ossl_unused void *cctx, ossl_unused void *provctx)
{
    return ossl_cipher_gcm_get_ctx_params_list;
}

int ossl_gcm_get_ctx_params(void *vctx, OSSL_PARAM params[])
{
    PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
    size_t sz;
    struct ossl_cipher_gcm_get_ctx_params_st p;

    if (ctx == NULL || !ossl_cipher_gcm_get_ctx_params_decoder(params, &p))
        return 0;

    if (p.ivlen != NULL && !OSSL_PARAM_set_size_t(p.ivlen, ctx->ivlen)) {
        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
        return 0;
    }

    if (p.keylen != NULL && !OSSL_PARAM_set_size_t(p.keylen, ctx->keylen)) {
        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
        return 0;
    }

    if (p.taglen != NULL) {
        size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen : GCM_TAG_MAX_SIZE;

        if (!OSSL_PARAM_set_size_t(p.taglen, taglen)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
            return 0;
        }
    }

    /*
     * Note p.updiv and p.iv are aliases that get the same information,
     * so any code changes should be duplicated below.
     */
    if (p.iv != NULL) {
        if (!on_preupdate_generate_iv(ctx))
            return 0;
        if (p.iv->data != NULL && ctx->ivlen > p.iv->data_size) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
            return 0;
        }
        if (!OSSL_PARAM_set_octet_string_or_ptr(p.iv, ctx->iv, ctx->ivlen)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
            return 0;
        }
    }
    if (p.updiv != NULL) {
        if (!on_preupdate_generate_iv(ctx))
            return 0;
        if (p.updiv->data != NULL && ctx->ivlen > p.updiv->data_size) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
            return 0;
        }
        if (!OSSL_PARAM_set_octet_string_or_ptr(p.updiv, ctx->iv, ctx->ivlen)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
            return 0;
        }
    }

    if (p.pad != NULL && !OSSL_PARAM_set_size_t(p.pad, ctx->tls_aad_pad_sz)) {
        ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
        return 0;
    }

    if (p.tag != NULL) {
        if (!ctx->enc || ctx->taglen == UNINITIALISED_SIZET) {
            ERR_raise(ERR_LIB_PROV, PROV_R_TAG_NOT_SET);
            return 0;
        }
        if (p.tag->data == NULL) {
            /* size query: report the tag length, as for the iv above */
            sz = ctx->taglen;
        } else {
            sz = p.tag->data_size;
            if (sz > EVP_GCM_TLS_TAG_LEN || sz == 0) {
                ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
                return 0;
            }
        }

        if (!OSSL_PARAM_set_octet_string(p.tag, ctx->buf, sz)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
            return 0;
        }
    }

    if (p.ivgen != NULL)
        if (p.ivgen->data == NULL
            || p.ivgen->data_type != OSSL_PARAM_OCTET_STRING
            || !getivgen(ctx, p.ivgen->data, p.ivgen->data_size))
            return 0;

    if (p.gen != NULL && !OSSL_PARAM_set_uint(p.gen, ctx->iv_gen_rand))
        return 0;

    /*
     * Externally supplied IVs are permitted but not approved for encryption.
     * Approved tag lengths are 4, 8, and 12 through 16 bytes.
     * For encryption, requesting only a prefix of the generated tag does not
     * change the tag length used by the operation.
     */
    if (!OSSL_FIPS_IND_GET_PARAM_CONDITIONAL(p.ind,
            (!ctx->enc || ctx->iv_gen_rand)
                && gcm_fips_taglen_approved(ctx->taglen)))
        return 0;

    return 1;
}

const OSSL_PARAM *ossl_gcm_settable_ctx_params(
    ossl_unused void *cctx, ossl_unused void *provctx)
{
    return ossl_cipher_gcm_set_ctx_params_list;
}

int ossl_gcm_set_ctx_params(void *vctx, const OSSL_PARAM params[])
{
    PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
    size_t sz;
    void *vp;
    struct ossl_cipher_gcm_set_ctx_params_st p;

    if (ctx == NULL || !ossl_cipher_gcm_set_ctx_params_decoder(params, &p))
        return 0;

    if (p.tag != NULL) {
        vp = ctx->buf;
        if (!OSSL_PARAM_get_octet_string(p.tag, &vp, EVP_GCM_TLS_TAG_LEN, &sz)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
            return 0;
        }
        if (ctx->enc) {
            ERR_raise(ERR_LIB_PROV, PROV_R_TAG_NOT_NEEDED);
            return 0;
        }
        if (sz == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
            return 0;
        }
        ctx->taglen = sz;
    }

    if (p.ivlen != NULL) {
        if (!OSSL_PARAM_get_size_t(p.ivlen, &sz)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
            return 0;
        }
        if (sz == 0 || sz > sizeof(ctx->iv)) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
            return 0;
        }
        if (ctx->ivlen != sz) {
            /* If the iv was already set or autogenerated, it is invalid. */
            if (ctx->iv_state != IV_STATE_UNINITIALISED)
                ctx->iv_state = IV_STATE_FINISHED;
            ctx->ivlen = sz;
        }
    }

    if (p.aad != NULL) {
        if (p.aad->data_type != OSSL_PARAM_OCTET_STRING) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
            return 0;
        }
        sz = gcm_tls_init(ctx, p.aad->data, p.aad->data_size);
        if (sz == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_AAD);
            return 0;
        }
        ctx->tls_aad_pad_sz = sz;
    }

    if (p.fixed != NULL) {
        if (p.fixed->data_type != OSSL_PARAM_OCTET_STRING) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
            return 0;
        }
        if (gcm_tls_iv_set_fixed(ctx, p.fixed->data, p.fixed->data_size) == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
            return 0;
        }
    }

    if (p.inviv != NULL)
        if (p.inviv->data == NULL
            || p.inviv->data_type != OSSL_PARAM_OCTET_STRING
            || !setivinv(ctx, p.inviv->data, p.inviv->data_size))
            return 0;

    return 1;
}

int ossl_gcm_stream_update(void *vctx, unsigned char *out, size_t *outl,
    size_t outsize, const unsigned char *in, size_t inl)
{
    PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;

    if (inl == 0) {
        *outl = 0;
        return 1;
    }

    if (in == NULL) {
        ERR_raise(ERR_LIB_PROV, ERR_R_PASSED_NULL_PARAMETER);
        return 0;
    }

    if (outsize < inl) {
        ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
        return 0;
    }

    if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
        return 0;
    return 1;
}

int ossl_gcm_stream_final(void *vctx, unsigned char *out, size_t *outl,
    size_t outsize)
{
    PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;
    int i;

    if (!ossl_prov_is_running())
        return 0;

    i = gcm_cipher_internal(ctx, out, outl, NULL, 0);
    if (i <= 0)
        return 0;

    *outl = 0;
    return 1;
}

int ossl_gcm_cipher(void *vctx,
    unsigned char *out, size_t *outl, size_t outsize,
    const unsigned char *in, size_t inl)
{
    PROV_GCM_CTX *ctx = (PROV_GCM_CTX *)vctx;

    if (!ossl_prov_is_running())
        return 0;

    if (outsize < inl) {
        ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
        return 0;
    }

    if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
        return 0;

    *outl = inl;
    return 1;
}

/*
 * See SP800-38D (GCM) Section 8 "Uniqueness requirement on IVS and keys"
 *
 * See also 8.2.2 RBG-based construction.
 * Random construction consists of a free field (which can be NULL) and a
 * random field which will use a DRBG that can return at least 96 bits of
 * entropy strength. (The DRBG must be seeded by the FIPS module).
 */
static int gcm_iv_generate(PROV_GCM_CTX *ctx, int offset)
{
    int sz = (int)(ctx->ivlen - offset);

    /* Must be at least 96 bits */
    if (sz <= 0 || ctx->ivlen < GCM_IV_DEFAULT_SIZE)
        return 0;

    /* Use DRBG to generate random iv */
    if (RAND_bytes_ex(ctx->libctx, ctx->iv + offset, sz, 0) <= 0)
        return 0;
    ctx->iv_state = IV_STATE_BUFFERED;
    ctx->iv_gen_rand = 1;
    return 1;
}

/*
 * If we try to grab the iv before the update - it wont be generated yet,
 * so we generate it here for this case.
 */
static int on_preupdate_generate_iv(PROV_GCM_CTX *ctx)
{
    if (ctx->iv_state == IV_STATE_UNINITIALISED) {
        if (ctx->tls_aad_len != UNINITIALISED_SIZET)
            return 0;
        if (!ctx->enc || !gcm_iv_generate(ctx, 0))
            return 0;
    }
    return 1;
}

/* returns 1 on success, 0 on failure with a reason on the error queue */
static int gcm_cipher_internal(PROV_GCM_CTX *ctx, unsigned char *out,
    size_t *padlen, const unsigned char *in,
    size_t len)
{
    size_t olen = 0;
    int rv = 0;
    const PROV_GCM_HW *hw = ctx->hw;

    if (ctx->tls_aad_len != UNINITIALISED_SIZET)
        return gcm_tls_cipher(ctx, out, padlen, in, len);

    if (ctx->key_set == 0 || ctx->iv_state == IV_STATE_FINISHED) {
        ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
        goto err;
    }

    /*
     * FIPS requires generation of AES-GCM IV's inside the FIPS module.
     * The IV can still be set externally (the security policy will state that
     * this is not FIPS compliant). There are some applications
     * where setting the IV externally is the only option available.
     */
    if (ctx->iv_state == IV_STATE_UNINITIALISED) {
        if (ctx->enc == 0 || gcm_iv_generate(ctx, 0) == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            goto err;
        }
    }

    if (ctx->iv_state == IV_STATE_BUFFERED) {
        if (hw->setiv(ctx, ctx->iv, ctx->ivlen) == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            goto err;
        }
        ctx->iv_state = IV_STATE_COPIED;
    }

    if (in != NULL) {
        /*  The input is AAD if out is NULL */
        if (out == NULL) {
            int rv_aad = hw->aadupdate(ctx, in, len);

            if (rv_aad == -2) { /* AAD after payload */
                ERR_raise(ERR_LIB_PROV, PROV_R_UPDATE_CALL_OUT_OF_ORDER);
                goto err;
            }
            if (rv_aad <= 0) { /* AAD length overflow or other failure */
                ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
                goto err;
            }
        } else {
            /* The input is ciphertext OR plaintext */
            if (hw->cipherupdate(ctx, in, len, out) == 0) {
                ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
                goto err;
            }
        }
    } else {
        /* The tag must be set before actually decrypting data */
        if (!ctx->enc && ctx->taglen == UNINITIALISED_SIZET) {
            ERR_raise(ERR_LIB_PROV, PROV_R_TAG_NOT_SET);
            goto err;
        }
        if (hw->cipherfinal(ctx, ctx->buf) == 0) {
            if (ctx->enc == 0)
                ERR_raise(ERR_LIB_PROV, PROV_R_BAD_DECRYPT);
            else
                ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            goto err;
        }
        ctx->iv_state = IV_STATE_FINISHED; /* Don't reuse the IV */
        goto finish;
    }
    olen = len;
finish:
    rv = 1;
err:
    *padlen = olen;
    return rv;
}

static int gcm_tls_init(PROV_GCM_CTX *dat, unsigned char *aad, size_t aad_len)
{
    unsigned char *buf;
    size_t len;

    if (!ossl_prov_is_running() || aad_len != EVP_AEAD_TLS1_AAD_LEN)
        return 0;

    /* Save the aad for later use. */
    buf = dat->buf;
    memcpy(buf, aad, aad_len);
    dat->tls_aad_len = aad_len;

    len = buf[aad_len - 2] << 8 | buf[aad_len - 1];
    /* Correct length for explicit iv. */
    if (len < EVP_GCM_TLS_EXPLICIT_IV_LEN)
        return 0;
    len -= EVP_GCM_TLS_EXPLICIT_IV_LEN;

    /* If decrypting correct for tag too. */
    if (!dat->enc) {
        if (len < EVP_GCM_TLS_TAG_LEN)
            return 0;
        len -= EVP_GCM_TLS_TAG_LEN;
    }
    buf[aad_len - 2] = (unsigned char)(len >> 8);
    buf[aad_len - 1] = (unsigned char)(len & 0xff);
    /* Extra padding: tag appended to record. */
    return EVP_GCM_TLS_TAG_LEN;
}

static int gcm_tls_iv_set_fixed(PROV_GCM_CTX *ctx, unsigned char *iv,
    size_t len)
{
    /* Special case: -1 length restores whole IV */
    if (len == (size_t)-1) {
        memcpy(ctx->iv, iv, ctx->ivlen);
        ctx->iv_gen_rand = 0;
        ctx->iv_gen = 1;
        ctx->iv_state = IV_STATE_BUFFERED;
        return 1;
    }
    /* Fixed field must be at least 4 bytes and invocation field at least 8 */
    if (len < EVP_GCM_TLS_FIXED_IV_LEN
        || len > ctx->ivlen
        || (ctx->ivlen - len) < EVP_GCM_TLS_EXPLICIT_IV_LEN)
        return 0;
    if (len > 0)
        memcpy(ctx->iv, iv, len);
    if (ctx->enc) {
        if (RAND_bytes_ex(ctx->libctx, ctx->iv + len, ctx->ivlen - len, 0) <= 0)
            return 0;
        ctx->iv_gen_rand = 1;
    }
    ctx->iv_gen = 1;
    ctx->iv_state = IV_STATE_BUFFERED;
    return 1;
}

/*
 * Handle TLS GCM packet format. This consists of the last portion of the IV
 * followed by the payload and finally the tag. On encrypt generate IV,
 * encrypt payload and write the tag. On verify retrieve IV, decrypt payload
 * and verify tag.
 */
static int gcm_tls_cipher(PROV_GCM_CTX *ctx, unsigned char *out, size_t *padlen,
    const unsigned char *in, size_t len)
{
    int rv = 0;
    size_t arg = EVP_GCM_TLS_EXPLICIT_IV_LEN;
    size_t plen = 0;
    unsigned char *tag = NULL;

    if (ossl_prov_is_running() == 0 || ctx->key_set == 0) {
        ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
        goto err;
    }

    /* Encrypt/decrypt must be performed in place */
    if (out != in || len < (EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN)) {
        ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
        goto err;
    }

    /*
     * Check for too many keys as per FIPS 140-2 IG A.5 "Key/IV Pair Uniqueness
     * Requirements from SP 800-38D".  The requirements is for one party to the
     * communication to fail after 2^64 - 1 keys.  We do this on the encrypting
     * side only.
     */
    if (ctx->enc && ++ctx->tls_enc_records == 0) {
        ERR_raise(ERR_LIB_PROV, PROV_R_TOO_MANY_RECORDS);
        goto err;
    }

    /*
     * Set IV from start of buffer or generate IV and write to start of
     * buffer.
     */
    if (ctx->enc) {
        if (getivgen(ctx, out, arg) == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            goto err;
        }
    } else {
        if (setivinv(ctx, out, arg) == 0) {
            ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
            goto err;
        }
    }

    /* Fix buffer and length to point to payload */
    in += EVP_GCM_TLS_EXPLICIT_IV_LEN;
    out += EVP_GCM_TLS_EXPLICIT_IV_LEN;
    len -= EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;

    tag = ctx->enc ? out + len : (unsigned char *)in + len;
    if (!ctx->hw->oneshot(ctx, ctx->buf, ctx->tls_aad_len, in, len, out, tag,
            EVP_GCM_TLS_TAG_LEN)) {
        if (!ctx->enc)
            OPENSSL_cleanse(out, len);
        ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
        goto err;
    }
    if (ctx->enc)
        plen = len + EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
    else
        plen = len;

    rv = 1;
err:
    ctx->iv_state = IV_STATE_FINISHED;
    ctx->tls_aad_len = UNINITIALISED_SIZET;
    *padlen = plen;
    return rv;
}

Coverage Report

Created: 2026-10-28 07:07

Line	Count	Source
1		/*
2		* Copyright 2019-2026 The OpenSSL Project Authors. All Rights Reserved.
3		*
4		* Licensed under the Apache License 2.0 (the "License"). You may not use
5		* this file except in compliance with the License. You can obtain a copy
6		* in the file LICENSE in the source distribution or at
7		* https://www.openssl.org/source/license.html
8		*/
9
10		/* Dispatch functions for gcm mode */
11
12		#include <openssl/rand.h>
13		#include <openssl/proverr.h>
14		#include "prov/ciphercommon.h"
15		#include "prov/ciphercommon_gcm.h"
16		#include "prov/providercommon.h"
17		#include "prov/provider_ctx.h"
18		#include "fips/fipsindicator.h"
19
20		#include "providers/implementations/ciphers/ciphercommon_gcm.inc"
21
22		static int gcm_tls_init(PROV_GCM_CTX dat, unsigned char aad, size_t aad_len);
23		static int gcm_tls_iv_set_fixed(PROV_GCM_CTX ctx, unsigned char iv,
24		size_t len);
25		static int gcm_tls_cipher(PROV_GCM_CTX ctx, unsigned char out, size_t *padlen,
26		const unsigned char *in, size_t len);
27		static int gcm_cipher_internal(PROV_GCM_CTX ctx, unsigned char out,
28		size_t padlen, const unsigned char in,
29		size_t len);
30		static int on_preupdate_generate_iv(PROV_GCM_CTX *ctx);
31
32		#ifdef FIPS_MODULE
33		static int gcm_fips_taglen_approved(size_t taglen)
34		{
35		return taglen == UNINITIALISED_SIZET \|\| taglen == 4 \|\| taglen == 8
36		\|\| (taglen >= 12 && taglen <= GCM_TAG_MAX_SIZE);
37		}
38		#endif
39
40		/*
41		* Called from EVP_CipherInit when there is currently no context via
42		* the new_ctx() function
43		*/
44		void ossl_gcm_initctx(void provctx, PROV_GCM_CTX ctx, size_t keybits,
45		const PROV_GCM_HW *hw)
46	0	{
47	0	ctx->pad = 1;
48	0	ctx->mode = EVP_CIPH_GCM_MODE;
49	0	ctx->taglen = UNINITIALISED_SIZET;
50	0	ctx->tls_aad_len = UNINITIALISED_SIZET;
51	0	ctx->ivlen = (EVP_GCM_TLS_FIXED_IV_LEN + EVP_GCM_TLS_EXPLICIT_IV_LEN);
52	0	ctx->keylen = keybits / 8;
53	0	ctx->hw = hw;
54	0	ctx->libctx = PROV_LIBCTX_OF(provctx);
55	0	}
56
57		/*
58		* Called by EVP_CipherInit via the _einit and _dinit functions
59		*/
60		static int gcm_init(void vctx, const unsigned char key, size_t keylen,
61		const unsigned char *iv, size_t ivlen,
62		const OSSL_PARAM params[], int enc)
63	0	{
64	0	PROV_GCM_CTX ctx = (PROV_GCM_CTX )vctx;
65
66	0	if (!ossl_prov_is_running())
67	0	return 0;
68
69	0	ctx->enc = enc;
70
71	0	if (iv != NULL) {
72	0	if (ivlen == 0 \|\| ivlen > sizeof(ctx->iv)) {
73	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
74	0	return 0;
75	0	}
76	0	ctx->iv_gen_rand = 0;
77	0	ctx->ivlen = ivlen;
78	0	memcpy(ctx->iv, iv, ivlen);
79	0	ctx->iv_state = IV_STATE_BUFFERED;
80	0	}
81
82	0	if (key != NULL) {
83	0	if (keylen != ctx->keylen) {
84	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
85	0	return 0;
86	0	}
87	0	if (!ctx->hw->setkey(ctx, key, ctx->keylen))
88	0	return 0;
89	0	ctx->tls_enc_records = 0;
90	0	}
91	0	return ossl_gcm_set_ctx_params(ctx, params);
92	0	}
93
94		int ossl_gcm_einit(void vctx, const unsigned char key, size_t keylen,
95		const unsigned char *iv, size_t ivlen,
96		const OSSL_PARAM params[])
97	0	{
98	0	return gcm_init(vctx, key, keylen, iv, ivlen, params, 1);
99	0	}
100
101		int ossl_gcm_dinit(void vctx, const unsigned char key, size_t keylen,
102		const unsigned char *iv, size_t ivlen,
103		const OSSL_PARAM params[])
104	0	{
105	0	return gcm_init(vctx, key, keylen, iv, ivlen, params, 0);
106	0	}
107
108		/* increment counter (64-bit int) by 1 */
109		static void ctr64_inc(unsigned char *counter)
110	0	{
111	0	int n = 8;
112	0	unsigned char c;
113
114	0	do {
115	0	--n;
116	0	c = counter[n];
117	0	++c;
118	0	counter[n] = c;
119	0	if (c > 0)
120	0	return;
121	0	} while (n > 0);
122	0	}
123
124		static int getivgen(PROV_GCM_CTX ctx, unsigned char out, size_t olen)
125	0	{
126	0	if (!ctx->iv_gen
127	0	\|\| !ctx->key_set
128	0	\|\| !ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
129	0	return 0;
130	0	if (olen == 0 \|\| olen > ctx->ivlen)
131	0	olen = ctx->ivlen;
132	0	memcpy(out, ctx->iv + ctx->ivlen - olen, olen);
133		/*
134		* Invocation field will be at least 8 bytes in size and so no need
135		* to check wrap around or increment more than last 8 bytes.
136		*/
137	0	ctr64_inc(ctx->iv + ctx->ivlen - 8);
138	0	ctx->iv_state = IV_STATE_COPIED;
139	0	return 1;
140	0	}
141
142		static int setivinv(PROV_GCM_CTX ctx, unsigned char in, size_t inl)
143	0	{
144	0	if (!ctx->iv_gen
145	0	\|\| !ctx->key_set
146	0	\|\| ctx->enc)
147	0	return 0;
148
149	0	memcpy(ctx->iv + ctx->ivlen - inl, in, inl);
150	0	if (!ctx->hw->setiv(ctx, ctx->iv, ctx->ivlen))
151	0	return 0;
152	0	ctx->iv_state = IV_STATE_COPIED;
153	0	return 1;
154	0	}
155
156		const OSSL_PARAM *ossl_gcm_gettable_ctx_params(
157		ossl_unused void cctx, ossl_unused void provctx)
158	7	{
159	7	return ossl_cipher_gcm_get_ctx_params_list;
160	7	}
161
162		int ossl_gcm_get_ctx_params(void *vctx, OSSL_PARAM params[])
163	0	{
164	0	PROV_GCM_CTX ctx = (PROV_GCM_CTX )vctx;
165	0	size_t sz;
166	0	struct ossl_cipher_gcm_get_ctx_params_st p;
167
168	0	if (ctx == NULL \|\| !ossl_cipher_gcm_get_ctx_params_decoder(params, &p))
169	0	return 0;
170
171	0	if (p.ivlen != NULL && !OSSL_PARAM_set_size_t(p.ivlen, ctx->ivlen)) {
172	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
173	0	return 0;
174	0	}
175
176	0	if (p.keylen != NULL && !OSSL_PARAM_set_size_t(p.keylen, ctx->keylen)) {
177	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
178	0	return 0;
179	0	}
180
181	0	if (p.taglen != NULL) {
182	0	size_t taglen = (ctx->taglen != UNINITIALISED_SIZET) ? ctx->taglen : GCM_TAG_MAX_SIZE;
183
184	0	if (!OSSL_PARAM_set_size_t(p.taglen, taglen)) {
185	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
186	0	return 0;
187	0	}
188	0	}
189
190		/*
191		* Note p.updiv and p.iv are aliases that get the same information,
192		* so any code changes should be duplicated below.
193		*/
194	0	if (p.iv != NULL) {
195	0	if (!on_preupdate_generate_iv(ctx))
196	0	return 0;
197	0	if (p.iv->data != NULL && ctx->ivlen > p.iv->data_size) {
198	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
199	0	return 0;
200	0	}
201	0	if (!OSSL_PARAM_set_octet_string_or_ptr(p.iv, ctx->iv, ctx->ivlen)) {
202	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
203	0	return 0;
204	0	}
205	0	}
206	0	if (p.updiv != NULL) {
207	0	if (!on_preupdate_generate_iv(ctx))
208	0	return 0;
209	0	if (p.updiv->data != NULL && ctx->ivlen > p.updiv->data_size) {
210	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
211	0	return 0;
212	0	}
213	0	if (!OSSL_PARAM_set_octet_string_or_ptr(p.updiv, ctx->iv, ctx->ivlen)) {
214	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
215	0	return 0;
216	0	}
217	0	}
218
219	0	if (p.pad != NULL && !OSSL_PARAM_set_size_t(p.pad, ctx->tls_aad_pad_sz)) {
220	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
221	0	return 0;
222	0	}
223
224	0	if (p.tag != NULL) {
225	0	if (!ctx->enc \|\| ctx->taglen == UNINITIALISED_SIZET) {
226	0	ERR_raise(ERR_LIB_PROV, PROV_R_TAG_NOT_SET);
227	0	return 0;
228	0	}
229	0	if (p.tag->data == NULL) {
230		/* size query: report the tag length, as for the iv above */
231	0	sz = ctx->taglen;
232	0	} else {
233	0	sz = p.tag->data_size;
234	0	if (sz > EVP_GCM_TLS_TAG_LEN \|\| sz == 0) {
235	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
236	0	return 0;
237	0	}
238	0	}
239
240	0	if (!OSSL_PARAM_set_octet_string(p.tag, ctx->buf, sz)) {
241	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_SET_PARAMETER);
242	0	return 0;
243	0	}
244	0	}
245
246	0	if (p.ivgen != NULL)
247	0	if (p.ivgen->data == NULL
248	0	\|\| p.ivgen->data_type != OSSL_PARAM_OCTET_STRING
249	0	\|\| !getivgen(ctx, p.ivgen->data, p.ivgen->data_size))
250	0	return 0;
251
252	0	if (p.gen != NULL && !OSSL_PARAM_set_uint(p.gen, ctx->iv_gen_rand))
253	0	return 0;
254
255		/*
256		* Externally supplied IVs are permitted but not approved for encryption.
257		* Approved tag lengths are 4, 8, and 12 through 16 bytes.
258		* For encryption, requesting only a prefix of the generated tag does not
259		* change the tag length used by the operation.
260		*/
261	0	if (!OSSL_FIPS_IND_GET_PARAM_CONDITIONAL(p.ind,
262	0	(!ctx->enc \|\| ctx->iv_gen_rand)
263	0	&& gcm_fips_taglen_approved(ctx->taglen)))
264	0	return 0;
265
266	0	return 1;
267	0	}
268
269		const OSSL_PARAM *ossl_gcm_settable_ctx_params(
270		ossl_unused void cctx, ossl_unused void provctx)
271	0	{
272	0	return ossl_cipher_gcm_set_ctx_params_list;
273	0	}
274
275		int ossl_gcm_set_ctx_params(void *vctx, const OSSL_PARAM params[])
276	0	{
277	0	PROV_GCM_CTX ctx = (PROV_GCM_CTX )vctx;
278	0	size_t sz;
279	0	void *vp;
280	0	struct ossl_cipher_gcm_set_ctx_params_st p;
281
282	0	if (ctx == NULL \|\| !ossl_cipher_gcm_set_ctx_params_decoder(params, &p))
283	0	return 0;
284
285	0	if (p.tag != NULL) {
286	0	vp = ctx->buf;
287	0	if (!OSSL_PARAM_get_octet_string(p.tag, &vp, EVP_GCM_TLS_TAG_LEN, &sz)) {
288	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
289	0	return 0;
290	0	}
291	0	if (ctx->enc) {
292	0	ERR_raise(ERR_LIB_PROV, PROV_R_TAG_NOT_NEEDED);
293	0	return 0;
294	0	}
295	0	if (sz == 0) {
296	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_TAG);
297	0	return 0;
298	0	}
299	0	ctx->taglen = sz;
300	0	}
301
302	0	if (p.ivlen != NULL) {
303	0	if (!OSSL_PARAM_get_size_t(p.ivlen, &sz)) {
304	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
305	0	return 0;
306	0	}
307	0	if (sz == 0 \|\| sz > sizeof(ctx->iv)) {
308	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_IV_LENGTH);
309	0	return 0;
310	0	}
311	0	if (ctx->ivlen != sz) {
312		/* If the iv was already set or autogenerated, it is invalid. */
313	0	if (ctx->iv_state != IV_STATE_UNINITIALISED)
314	0	ctx->iv_state = IV_STATE_FINISHED;
315	0	ctx->ivlen = sz;
316	0	}
317	0	}
318
319	0	if (p.aad != NULL) {
320	0	if (p.aad->data_type != OSSL_PARAM_OCTET_STRING) {
321	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
322	0	return 0;
323	0	}
324	0	sz = gcm_tls_init(ctx, p.aad->data, p.aad->data_size);
325	0	if (sz == 0) {
326	0	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_AAD);
327	0	return 0;
328	0	}
329	0	ctx->tls_aad_pad_sz = sz;
330	0	}
331
332	0	if (p.fixed != NULL) {
333	0	if (p.fixed->data_type != OSSL_PARAM_OCTET_STRING) {
334	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
335	0	return 0;
336	0	}
337	0	if (gcm_tls_iv_set_fixed(ctx, p.fixed->data, p.fixed->data_size) == 0) {
338	0	ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GET_PARAMETER);
339	0	return 0;
340	0	}
341	0	}
342
343	0	if (p.inviv != NULL)
344	0	if (p.inviv->data == NULL
345	0	\|\| p.inviv->data_type != OSSL_PARAM_OCTET_STRING
346	0	\|\| !setivinv(ctx, p.inviv->data, p.inviv->data_size))
347	0	return 0;
348
349	0	return 1;
350	0	}
351
352		int ossl_gcm_stream_update(void vctx, unsigned char out, size_t *outl,
353		size_t outsize, const unsigned char *in, size_t inl)
354	0	{
355	0	PROV_GCM_CTX ctx = (PROV_GCM_CTX )vctx;
356
357	0	if (inl == 0) {
358	0	*outl = 0;
359	0	return 1;
360	0	}
361
362	0	if (in == NULL) {
363	0	ERR_raise(ERR_LIB_PROV, ERR_R_PASSED_NULL_PARAMETER);
364	0	return 0;
365	0	}
366
367	0	if (outsize < inl) {
368	0	ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
369	0	return 0;
370	0	}
371
372	0	if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
373	0	return 0;
374	0	return 1;
375	0	}
376
377		int ossl_gcm_stream_final(void vctx, unsigned char out, size_t *outl,
378		size_t outsize)
379	0	{
380	0	PROV_GCM_CTX ctx = (PROV_GCM_CTX )vctx;
381	0	int i;
382
383	0	if (!ossl_prov_is_running())
384	0	return 0;
385
386	0	i = gcm_cipher_internal(ctx, out, outl, NULL, 0);
387	0	if (i <= 0)
388	0	return 0;
389
390	0	*outl = 0;
391	0	return 1;
392	0	}
393
394		int ossl_gcm_cipher(void *vctx,
395		unsigned char out, size_t outl, size_t outsize,
396		const unsigned char *in, size_t inl)
397	0	{
398	0	PROV_GCM_CTX ctx = (PROV_GCM_CTX )vctx;
399
400	0	if (!ossl_prov_is_running())
401	0	return 0;
402
403	0	if (outsize < inl) {
404	0	ERR_raise(ERR_LIB_PROV, PROV_R_OUTPUT_BUFFER_TOO_SMALL);
405	0	return 0;
406	0	}
407
408	0	if (gcm_cipher_internal(ctx, out, outl, in, inl) <= 0)
409	0	return 0;
410
411	0	*outl = inl;
412	0	return 1;
413	0	}
414
415		/*
416		* See SP800-38D (GCM) Section 8 "Uniqueness requirement on IVS and keys"
417		*
418		* See also 8.2.2 RBG-based construction.
419		* Random construction consists of a free field (which can be NULL) and a
420		* random field which will use a DRBG that can return at least 96 bits of
421		* entropy strength. (The DRBG must be seeded by the FIPS module).
422		*/
423		static int gcm_iv_generate(PROV_GCM_CTX *ctx, int offset)
424	0	{
425	0	int sz = (int)(ctx->ivlen - offset);
426
427		/* Must be at least 96 bits */
428	0	if (sz <= 0 \|\| ctx->ivlen < GCM_IV_DEFAULT_SIZE)
429	0	return 0;
430
431		/* Use DRBG to generate random iv */
432	0	if (RAND_bytes_ex(ctx->libctx, ctx->iv + offset, sz, 0) <= 0)
433	0	return 0;
434	0	ctx->iv_state = IV_STATE_BUFFERED;
435	0	ctx->iv_gen_rand = 1;
436	0	return 1;
437	0	}
438
439		/*
440		* If we try to grab the iv before the update - it wont be generated yet,
441		* so we generate it here for this case.
442		*/
443		static int on_preupdate_generate_iv(PROV_GCM_CTX *ctx)
444	0	{
445	0	if (ctx->iv_state == IV_STATE_UNINITIALISED) {
446	0	if (ctx->tls_aad_len != UNINITIALISED_SIZET)
447	0	return 0;
448	0	if (!ctx->enc \|\| !gcm_iv_generate(ctx, 0))
449	0	return 0;
450	0	}
451	0	return 1;
452	0	}
453
454		/* returns 1 on success, 0 on failure with a reason on the error queue */
455		static int gcm_cipher_internal(PROV_GCM_CTX ctx, unsigned char out,
456		size_t padlen, const unsigned char in,
457		size_t len)
458	0	{
459	0	size_t olen = 0;
460	0	int rv = 0;
461	0	const PROV_GCM_HW *hw = ctx->hw;
462
463	0	if (ctx->tls_aad_len != UNINITIALISED_SIZET)
464	0	return gcm_tls_cipher(ctx, out, padlen, in, len);
465
466	0	if (ctx->key_set == 0 \|\| ctx->iv_state == IV_STATE_FINISHED) {
467	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
468	0	goto err;
469	0	}
470
471		/*
472		* FIPS requires generation of AES-GCM IV's inside the FIPS module.
473		* The IV can still be set externally (the security policy will state that
474		* this is not FIPS compliant). There are some applications
475		* where setting the IV externally is the only option available.
476		*/
477	0	if (ctx->iv_state == IV_STATE_UNINITIALISED) {
478	0	if (ctx->enc == 0 \|\| gcm_iv_generate(ctx, 0) == 0) {
479	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
480	0	goto err;
481	0	}
482	0	}
483
484	0	if (ctx->iv_state == IV_STATE_BUFFERED) {
485	0	if (hw->setiv(ctx, ctx->iv, ctx->ivlen) == 0) {
486	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
487	0	goto err;
488	0	}
489	0	ctx->iv_state = IV_STATE_COPIED;
490	0	}
491
492	0	if (in != NULL) {
493		/* The input is AAD if out is NULL */
494	0	if (out == NULL) {
495	0	int rv_aad = hw->aadupdate(ctx, in, len);
496
497	0	if (rv_aad == -2) { /* AAD after payload */
498	0	ERR_raise(ERR_LIB_PROV, PROV_R_UPDATE_CALL_OUT_OF_ORDER);
499	0	goto err;
500	0	}
501	0	if (rv_aad <= 0) { /* AAD length overflow or other failure */
502	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
503	0	goto err;
504	0	}
505	0	} else {
506		/* The input is ciphertext OR plaintext */
507	0	if (hw->cipherupdate(ctx, in, len, out) == 0) {
508	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
509	0	goto err;
510	0	}
511	0	}
512	0	} else {
513		/* The tag must be set before actually decrypting data */
514	0	if (!ctx->enc && ctx->taglen == UNINITIALISED_SIZET) {
515	0	ERR_raise(ERR_LIB_PROV, PROV_R_TAG_NOT_SET);
516	0	goto err;
517	0	}
518	0	if (hw->cipherfinal(ctx, ctx->buf) == 0) {
519	0	if (ctx->enc == 0)
520	0	ERR_raise(ERR_LIB_PROV, PROV_R_BAD_DECRYPT);
521	0	else
522	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
523	0	goto err;
524	0	}
525	0	ctx->iv_state = IV_STATE_FINISHED; /* Don't reuse the IV */
526	0	goto finish;
527	0	}
528	0	olen = len;
529	0	finish:
530	0	rv = 1;
531	0	err:
532	0	*padlen = olen;
533	0	return rv;
534	0	}
535
536		static int gcm_tls_init(PROV_GCM_CTX dat, unsigned char aad, size_t aad_len)
537	0	{
538	0	unsigned char *buf;
539	0	size_t len;
540
541	0	if (!ossl_prov_is_running() \|\| aad_len != EVP_AEAD_TLS1_AAD_LEN)
542	0	return 0;
543
544		/* Save the aad for later use. */
545	0	buf = dat->buf;
546	0	memcpy(buf, aad, aad_len);
547	0	dat->tls_aad_len = aad_len;
548
549	0	len = buf[aad_len - 2] << 8 \| buf[aad_len - 1];
550		/* Correct length for explicit iv. */
551	0	if (len < EVP_GCM_TLS_EXPLICIT_IV_LEN)
552	0	return 0;
553	0	len -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
554
555		/* If decrypting correct for tag too. */
556	0	if (!dat->enc) {
557	0	if (len < EVP_GCM_TLS_TAG_LEN)
558	0	return 0;
559	0	len -= EVP_GCM_TLS_TAG_LEN;
560	0	}
561	0	buf[aad_len - 2] = (unsigned char)(len >> 8);
562	0	buf[aad_len - 1] = (unsigned char)(len & 0xff);
563		/* Extra padding: tag appended to record. */
564	0	return EVP_GCM_TLS_TAG_LEN;
565	0	}
566
567		static int gcm_tls_iv_set_fixed(PROV_GCM_CTX ctx, unsigned char iv,
568		size_t len)
569	0	{
570		/* Special case: -1 length restores whole IV */
571	0	if (len == (size_t)-1) {
572	0	memcpy(ctx->iv, iv, ctx->ivlen);
573	0	ctx->iv_gen_rand = 0;
574	0	ctx->iv_gen = 1;
575	0	ctx->iv_state = IV_STATE_BUFFERED;
576	0	return 1;
577	0	}
578		/* Fixed field must be at least 4 bytes and invocation field at least 8 */
579	0	if (len < EVP_GCM_TLS_FIXED_IV_LEN
580	0	\|\| len > ctx->ivlen
581	0	\|\| (ctx->ivlen - len) < EVP_GCM_TLS_EXPLICIT_IV_LEN)
582	0	return 0;
583	0	if (len > 0)
584	0	memcpy(ctx->iv, iv, len);
585	0	if (ctx->enc) {
586	0	if (RAND_bytes_ex(ctx->libctx, ctx->iv + len, ctx->ivlen - len, 0) <= 0)
587	0	return 0;
588	0	ctx->iv_gen_rand = 1;
589	0	}
590	0	ctx->iv_gen = 1;
591	0	ctx->iv_state = IV_STATE_BUFFERED;
592	0	return 1;
593	0	}
594
595		/*
596		* Handle TLS GCM packet format. This consists of the last portion of the IV
597		* followed by the payload and finally the tag. On encrypt generate IV,
598		* encrypt payload and write the tag. On verify retrieve IV, decrypt payload
599		* and verify tag.
600		*/
601		static int gcm_tls_cipher(PROV_GCM_CTX ctx, unsigned char out, size_t *padlen,
602		const unsigned char *in, size_t len)
603	0	{
604	0	int rv = 0;
605	0	size_t arg = EVP_GCM_TLS_EXPLICIT_IV_LEN;
606	0	size_t plen = 0;
607	0	unsigned char *tag = NULL;
608
609	0	if (ossl_prov_is_running() == 0 \|\| ctx->key_set == 0) {
610	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
611	0	goto err;
612	0	}
613
614		/* Encrypt/decrypt must be performed in place */
615	0	if (out != in \|\| len < (EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN)) {
616	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
617	0	goto err;
618	0	}
619
620		/*
621		* Check for too many keys as per FIPS 140-2 IG A.5 "Key/IV Pair Uniqueness
622		* Requirements from SP 800-38D". The requirements is for one party to the
623		* communication to fail after 2^64 - 1 keys. We do this on the encrypting
624		* side only.
625		*/
626	0	if (ctx->enc && ++ctx->tls_enc_records == 0) {
627	0	ERR_raise(ERR_LIB_PROV, PROV_R_TOO_MANY_RECORDS);
628	0	goto err;
629	0	}
630
631		/*
632		* Set IV from start of buffer or generate IV and write to start of
633		* buffer.
634		*/
635	0	if (ctx->enc) {
636	0	if (getivgen(ctx, out, arg) == 0) {
637	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
638	0	goto err;
639	0	}
640	0	} else {
641	0	if (setivinv(ctx, out, arg) == 0) {
642	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
643	0	goto err;
644	0	}
645	0	}
646
647		/* Fix buffer and length to point to payload */
648	0	in += EVP_GCM_TLS_EXPLICIT_IV_LEN;
649	0	out += EVP_GCM_TLS_EXPLICIT_IV_LEN;
650	0	len -= EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
651
652	0	tag = ctx->enc ? out + len : (unsigned char *)in + len;
653	0	if (!ctx->hw->oneshot(ctx, ctx->buf, ctx->tls_aad_len, in, len, out, tag,
654	0	EVP_GCM_TLS_TAG_LEN)) {
655	0	if (!ctx->enc)
656	0	OPENSSL_cleanse(out, len);
657	0	ERR_raise(ERR_LIB_PROV, PROV_R_CIPHER_OPERATION_FAILED);
658	0	goto err;
659	0	}
660	0	if (ctx->enc)
661	0	plen = len + EVP_GCM_TLS_EXPLICIT_IV_LEN + EVP_GCM_TLS_TAG_LEN;
662	0	else
663	0	plen = len;
664
665	0	rv = 1;
666	0	err:
667	0	ctx->iv_state = IV_STATE_FINISHED;
668	0	ctx->tls_aad_len = UNINITIALISED_SIZET;
669	0	*padlen = plen;
670	0	return rv;
671	0	}