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crypto: drbg - Convert to new rng interface
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This patch converts the DRBG implementation to the new low-level
rng interface.

This allows us to get rid of struct drbg_gen by using the new RNG
API instead.

Signed-off-by: Herbert Xu <[email protected]>
Acked-by: Stephan Mueller <[email protected]>
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@herbertx
herbertx committed Apr 22, 2015
1 parent 881cd6c commit 8fded59
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Showing 2 changed files with 66 additions and 107 deletions.
123 changes: 54 additions & 69 deletions crypto/drbg.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -235,7 +235,7 @@ static bool drbg_fips_continuous_test(struct drbg_state *drbg,
#ifdef CONFIG_CRYPTO_FIPS
int ret = 0;
/* skip test if we test the overall system */
if (drbg->test_data)
if (list_empty(&drbg->test_data.list))
return true;
/* only perform test in FIPS mode */
if (0 == fips_enabled)
Expand Down Expand Up @@ -1068,9 +1068,9 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
return -EINVAL;
}

if (drbg->test_data && drbg->test_data->testentropy) {
drbg_string_fill(&data1, drbg->test_data->testentropy->buf,
drbg->test_data->testentropy->len);
if (list_empty(&drbg->test_data.list)) {
drbg_string_fill(&data1, drbg->test_data.buf,
drbg->test_data.len);
pr_devel("DRBG: using test entropy\n");
} else {
/*
Expand Down Expand Up @@ -1471,15 +1471,16 @@ static int drbg_uninstantiate(struct drbg_state *drbg)
* Helper function for setting the test data in the DRBG
*
* @drbg DRBG state handle
* @test_data test data to sets
* @data test data
* @len test data length
*/
static inline void drbg_set_testdata(struct drbg_state *drbg,
struct drbg_test_data *test_data)
static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
const u8 *data, unsigned int len)
{
if (!test_data || !test_data->testentropy)
return;
mutex_lock(&drbg->drbg_mutex);;
drbg->test_data = test_data;
struct drbg_state *drbg = crypto_rng_ctx(tfm);

mutex_lock(&drbg->drbg_mutex);
drbg_string_fill(&drbg->test_data, data, len);
mutex_unlock(&drbg->drbg_mutex);
}

Expand Down Expand Up @@ -1645,63 +1646,49 @@ static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
* Generate random numbers invoked by the kernel crypto API:
* The API of the kernel crypto API is extended as follows:
*
* If dlen is larger than zero, rdata is interpreted as the output buffer
* where random data is to be stored.
*
* If dlen is zero, rdata is interpreted as a pointer to a struct drbg_gen
* which holds the additional information string that is used for the
* DRBG generation process. The output buffer that is to be used to store
* data is also pointed to by struct drbg_gen.
* src is additional input supplied to the RNG.
* slen is the length of src.
* dst is the output buffer where random data is to be stored.
* dlen is the length of dst.
*/
static int drbg_kcapi_random(struct crypto_rng *tfm, u8 *rdata,
unsigned int dlen)
static int drbg_kcapi_random(struct crypto_rng *tfm,
const u8 *src, unsigned int slen,
u8 *dst, unsigned int dlen)
{
struct drbg_state *drbg = crypto_rng_ctx(tfm);
if (0 < dlen) {
return drbg_generate_long(drbg, rdata, dlen, NULL);
} else {
struct drbg_gen *data = (struct drbg_gen *)rdata;
struct drbg_string addtl;
/* catch NULL pointer */
if (!data)
return 0;
drbg_set_testdata(drbg, data->test_data);
struct drbg_string *addtl = NULL;
struct drbg_string string;

if (slen) {
/* linked list variable is now local to allow modification */
drbg_string_fill(&addtl, data->addtl->buf, data->addtl->len);
return drbg_generate_long(drbg, data->outbuf, data->outlen,
&addtl);
drbg_string_fill(&string, src, slen);
addtl = &string;
}

return drbg_generate_long(drbg, dst, dlen, addtl);
}

/*
* Seed the DRBG invoked by the kernel crypto API
* Similar to the generate function of drbg_kcapi_random, this
* function extends the kernel crypto API interface with struct drbg_gen
*/
static int drbg_kcapi_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
static int drbg_kcapi_seed(struct crypto_rng *tfm,
const u8 *seed, unsigned int slen)
{
struct drbg_state *drbg = crypto_rng_ctx(tfm);
struct crypto_tfm *tfm_base = crypto_rng_tfm(tfm);
bool pr = false;
struct drbg_string seed_string;
struct drbg_string string;
struct drbg_string *seed_string = NULL;
int coreref = 0;

drbg_convert_tfm_core(crypto_tfm_alg_driver_name(tfm_base), &coreref,
&pr);
if (0 < slen) {
drbg_string_fill(&seed_string, seed, slen);
return drbg_instantiate(drbg, &seed_string, coreref, pr);
} else {
struct drbg_gen *data = (struct drbg_gen *)seed;
/* allow invocation of API call with NULL, 0 */
if (!data)
return drbg_instantiate(drbg, NULL, coreref, pr);
drbg_set_testdata(drbg, data->test_data);
/* linked list variable is now local to allow modification */
drbg_string_fill(&seed_string, data->addtl->buf,
data->addtl->len);
return drbg_instantiate(drbg, &seed_string, coreref, pr);
drbg_string_fill(&string, seed, slen);
seed_string = &string;
}

return drbg_instantiate(drbg, seed_string, coreref, pr);
}

/***************************************************************
Expand Down Expand Up @@ -1793,50 +1780,48 @@ static inline int __init drbg_healthcheck_sanity(void)
#endif /* CONFIG_CRYPTO_FIPS */
}

static struct crypto_alg drbg_algs[22];
static struct rng_alg drbg_algs[22];

/*
* Fill the array drbg_algs used to register the different DRBGs
* with the kernel crypto API. To fill the array, the information
* from drbg_cores[] is used.
*/
static inline void __init drbg_fill_array(struct crypto_alg *alg,
static inline void __init drbg_fill_array(struct rng_alg *alg,
const struct drbg_core *core, int pr)
{
int pos = 0;
static int priority = 100;

memset(alg, 0, sizeof(struct crypto_alg));
memcpy(alg->cra_name, "stdrng", 6);
memcpy(alg->base.cra_name, "stdrng", 6);
if (pr) {
memcpy(alg->cra_driver_name, "drbg_pr_", 8);
memcpy(alg->base.cra_driver_name, "drbg_pr_", 8);
pos = 8;
} else {
memcpy(alg->cra_driver_name, "drbg_nopr_", 10);
memcpy(alg->base.cra_driver_name, "drbg_nopr_", 10);
pos = 10;
}
memcpy(alg->cra_driver_name + pos, core->cra_name,
memcpy(alg->base.cra_driver_name + pos, core->cra_name,
strlen(core->cra_name));

alg->cra_priority = priority;
alg->base.cra_priority = priority;
priority++;
/*
* If FIPS mode enabled, the selected DRBG shall have the
* highest cra_priority over other stdrng instances to ensure
* it is selected.
*/
if (fips_enabled)
alg->cra_priority += 200;

alg->cra_flags = CRYPTO_ALG_TYPE_RNG;
alg->cra_ctxsize = sizeof(struct drbg_state);
alg->cra_type = &crypto_rng_type;
alg->cra_module = THIS_MODULE;
alg->cra_init = drbg_kcapi_init;
alg->cra_exit = drbg_kcapi_cleanup;
alg->cra_u.rng.rng_make_random = drbg_kcapi_random;
alg->cra_u.rng.rng_reset = drbg_kcapi_reset;
alg->cra_u.rng.seedsize = 0;
alg->base.cra_priority += 200;

alg->base.cra_ctxsize = sizeof(struct drbg_state);
alg->base.cra_module = THIS_MODULE;
alg->base.cra_init = drbg_kcapi_init;
alg->base.cra_exit = drbg_kcapi_cleanup;
alg->generate = drbg_kcapi_random;
alg->seed = drbg_kcapi_seed;
alg->set_ent = drbg_kcapi_set_entropy;
alg->seedsize = 0;
}

static int __init drbg_init(void)
Expand Down Expand Up @@ -1869,12 +1854,12 @@ static int __init drbg_init(void)
drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 1);
for (j = 0; ARRAY_SIZE(drbg_cores) > j; j++, i++)
drbg_fill_array(&drbg_algs[i], &drbg_cores[j], 0);
return crypto_register_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
return crypto_register_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
}

static void __exit drbg_exit(void)
{
crypto_unregister_algs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
crypto_unregister_rngs(drbg_algs, (ARRAY_SIZE(drbg_cores) * 2));
}

module_init(drbg_init);
Expand Down
50 changes: 12 additions & 38 deletions include/crypto/drbg.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,7 @@ struct drbg_state {
#endif
const struct drbg_state_ops *d_ops;
const struct drbg_core *core;
struct drbg_test_data *test_data;
struct drbg_string test_data;
};

static inline __u8 drbg_statelen(struct drbg_state *drbg)
Expand Down Expand Up @@ -176,20 +176,9 @@ static inline size_t drbg_max_requests(struct drbg_state *drbg)
#endif
}

/*
* kernel crypto API input data structure for DRBG generate in case dlen
* is set to 0
*/
struct drbg_gen {
unsigned char *outbuf; /* output buffer for random numbers */
unsigned int outlen; /* size of output buffer */
struct drbg_string *addtl; /* additional information string */
struct drbg_test_data *test_data; /* test data */
};

/*
* This is a wrapper to the kernel crypto API function of
* crypto_rng_get_bytes() to allow the caller to provide additional data.
* crypto_rng_generate() to allow the caller to provide additional data.
*
* @drng DRBG handle -- see crypto_rng_get_bytes
* @outbuf output buffer -- see crypto_rng_get_bytes
Expand All @@ -204,21 +193,15 @@ static inline int crypto_drbg_get_bytes_addtl(struct crypto_rng *drng,
unsigned char *outbuf, unsigned int outlen,
struct drbg_string *addtl)
{
int ret;
struct drbg_gen genbuf;
genbuf.outbuf = outbuf;
genbuf.outlen = outlen;
genbuf.addtl = addtl;
genbuf.test_data = NULL;
ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);
return ret;
return crypto_rng_generate(drng, addtl->buf, addtl->len,
outbuf, outlen);
}

/*
* TEST code
*
* This is a wrapper to the kernel crypto API function of
* crypto_rng_get_bytes() to allow the caller to provide additional data and
* crypto_rng_generate() to allow the caller to provide additional data and
* allow furnishing of test_data
*
* @drng DRBG handle -- see crypto_rng_get_bytes
Expand All @@ -236,14 +219,10 @@ static inline int crypto_drbg_get_bytes_addtl_test(struct crypto_rng *drng,
struct drbg_string *addtl,
struct drbg_test_data *test_data)
{
int ret;
struct drbg_gen genbuf;
genbuf.outbuf = outbuf;
genbuf.outlen = outlen;
genbuf.addtl = addtl;
genbuf.test_data = test_data;
ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);
return ret;
crypto_rng_set_entropy(drng, test_data->testentropy->buf,
test_data->testentropy->len);
return crypto_rng_generate(drng, addtl->buf, addtl->len,
outbuf, outlen);
}

/*
Expand All @@ -264,14 +243,9 @@ static inline int crypto_drbg_reset_test(struct crypto_rng *drng,
struct drbg_string *pers,
struct drbg_test_data *test_data)
{
int ret;
struct drbg_gen genbuf;
genbuf.outbuf = NULL;
genbuf.outlen = 0;
genbuf.addtl = pers;
genbuf.test_data = test_data;
ret = crypto_rng_reset(drng, (u8 *)&genbuf, 0);
return ret;
crypto_rng_set_entropy(drng, test_data->testentropy->buf,
test_data->testentropy->len);
return crypto_rng_reset(drng, pers->buf, pers->len);
}

/* DRBG type flags */
Expand Down

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