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-rw-r--r--crypto/err/openssl.txt1
-rw-r--r--crypto/include/internal/rand_int.h2
-rw-r--r--crypto/rand/drbg_ctr.c4
-rw-r--r--crypto/rand/drbg_hash.c4
-rw-r--r--crypto/rand/drbg_hmac.c4
-rw-r--r--crypto/rand/drbg_lib.c17
-rw-r--r--crypto/rand/rand_err.c1
-rw-r--r--crypto/rand/rand_lcl.h46
-rw-r--r--crypto/rand/rand_lib.c79
-rw-r--r--crypto/rand/rand_unix.c2
10 files changed, 116 insertions, 44 deletions
diff --git a/crypto/err/openssl.txt b/crypto/err/openssl.txt
index 84e639305b..489ccc0986 100644
--- a/crypto/err/openssl.txt
+++ b/crypto/err/openssl.txt
@@ -1016,6 +1016,7 @@ RAND_F_RAND_POOL_ACQUIRE_ENTROPY:122:rand_pool_acquire_entropy
RAND_F_RAND_POOL_ADD:103:rand_pool_add
RAND_F_RAND_POOL_ADD_BEGIN:113:rand_pool_add_begin
RAND_F_RAND_POOL_ADD_END:114:rand_pool_add_end
+RAND_F_RAND_POOL_ATTACH:124:rand_pool_attach
RAND_F_RAND_POOL_BYTES_NEEDED:115:rand_pool_bytes_needed
RAND_F_RAND_POOL_NEW:116:rand_pool_new
RAND_F_RAND_WRITE_FILE:112:RAND_write_file
diff --git a/crypto/include/internal/rand_int.h b/crypto/include/internal/rand_int.h
index d91ee4c934..3c966ab96e 100644
--- a/crypto/include/internal/rand_int.h
+++ b/crypto/include/internal/rand_int.h
@@ -53,6 +53,8 @@ void rand_drbg_cleanup_additional_data(unsigned char *out, size_t outlen);
* RAND_POOL functions
*/
RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len);
+RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
+ size_t entropy);
void rand_pool_free(RAND_POOL *pool);
const unsigned char *rand_pool_buffer(RAND_POOL *pool);
diff --git a/crypto/rand/drbg_ctr.c b/crypto/rand/drbg_ctr.c
index 0548237e7d..894c77d6eb 100644
--- a/crypto/rand/drbg_ctr.c
+++ b/crypto/rand/drbg_ctr.c
@@ -416,9 +416,9 @@ int drbg_ctr_init(RAND_DRBG *drbg)
return 0;
drbg->min_entropylen = ctr->keylen;
- drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen;
+ drbg->max_entropylen = DRBG_MAX_LENGTH;
drbg->min_noncelen = drbg->min_entropylen / 2;
- drbg->max_noncelen = DRBG_MINMAX_FACTOR * drbg->min_noncelen;
+ drbg->max_noncelen = DRBG_MAX_LENGTH;
drbg->max_perslen = DRBG_MAX_LENGTH;
drbg->max_adinlen = DRBG_MAX_LENGTH;
} else {
diff --git a/crypto/rand/drbg_hash.c b/crypto/rand/drbg_hash.c
index 9caf5b27be..cae567beb4 100644
--- a/crypto/rand/drbg_hash.c
+++ b/crypto/rand/drbg_hash.c
@@ -332,10 +332,10 @@ int drbg_hash_init(RAND_DRBG *drbg)
drbg->seedlen = HASH_PRNG_SMALL_SEEDLEN;
drbg->min_entropylen = drbg->strength / 8;
- drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen;
+ drbg->max_entropylen = DRBG_MAX_LENGTH;
drbg->min_noncelen = drbg->min_entropylen / 2;
- drbg->max_noncelen = DRBG_MINMAX_FACTOR * drbg->min_noncelen;
+ drbg->max_noncelen = DRBG_MAX_LENGTH;
drbg->max_perslen = DRBG_MAX_LENGTH;
drbg->max_adinlen = DRBG_MAX_LENGTH;
diff --git a/crypto/rand/drbg_hmac.c b/crypto/rand/drbg_hmac.c
index 25c5b0301c..424c88cb26 100644
--- a/crypto/rand/drbg_hmac.c
+++ b/crypto/rand/drbg_hmac.c
@@ -223,10 +223,10 @@ int drbg_hmac_init(RAND_DRBG *drbg)
drbg->seedlen = hmac->blocklen;
drbg->min_entropylen = drbg->strength / 8;
- drbg->max_entropylen = DRBG_MINMAX_FACTOR * drbg->min_entropylen;
+ drbg->max_entropylen = DRBG_MAX_LENGTH;
drbg->min_noncelen = drbg->min_entropylen / 2;
- drbg->max_noncelen = DRBG_MINMAX_FACTOR * drbg->min_noncelen;
+ drbg->max_noncelen = DRBG_MAX_LENGTH;
drbg->max_perslen = DRBG_MAX_LENGTH;
drbg->max_adinlen = DRBG_MAX_LENGTH;
diff --git a/crypto/rand/drbg_lib.c b/crypto/rand/drbg_lib.c
index c59f3f0026..36b20c9398 100644
--- a/crypto/rand/drbg_lib.c
+++ b/crypto/rand/drbg_lib.c
@@ -556,8 +556,10 @@ int rand_drbg_restart(RAND_DRBG *drbg,
if (drbg->pool != NULL) {
RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
+ drbg->state = DRBG_ERROR;
rand_pool_free(drbg->pool);
drbg->pool = NULL;
+ return 0;
}
if (buffer != NULL) {
@@ -565,24 +567,25 @@ int rand_drbg_restart(RAND_DRBG *drbg,
if (drbg->max_entropylen < len) {
RANDerr(RAND_F_RAND_DRBG_RESTART,
RAND_R_ENTROPY_INPUT_TOO_LONG);
+ drbg->state = DRBG_ERROR;
return 0;
}
if (entropy > 8 * len) {
RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
+ drbg->state = DRBG_ERROR;
return 0;
}
/* will be picked up by the rand_drbg_get_entropy() callback */
- drbg->pool = rand_pool_new(entropy, len, len);
+ drbg->pool = rand_pool_attach(buffer, len, entropy);
if (drbg->pool == NULL)
return 0;
-
- rand_pool_add(drbg->pool, buffer, len, entropy);
} else {
if (drbg->max_adinlen < len) {
RANDerr(RAND_F_RAND_DRBG_RESTART,
RAND_R_ADDITIONAL_INPUT_TOO_LONG);
+ drbg->state = DRBG_ERROR;
return 0;
}
adin = buffer;
@@ -1040,14 +1043,16 @@ static int drbg_add(const void *buf, int num, double randomness)
if (num < 0 || randomness < 0.0)
return 0;
- if (randomness > (double)drbg->max_entropylen) {
+ if (randomness > (double)RAND_DRBG_STRENGTH) {
/*
* The purpose of this check is to bound |randomness| by a
* relatively small value in order to prevent an integer
* overflow when multiplying by 8 in the rand_drbg_restart()
- * call below.
+ * call below. Note that randomness is measured in bytes,
+ * not bits, so this value corresponds to eight times the
+ * security strength.
*/
- return 0;
+ randomness = (double)RAND_DRBG_STRENGTH;
}
rand_drbg_lock(drbg);
diff --git a/crypto/rand/rand_err.c b/crypto/rand/rand_err.c
index 31480a6828..6a870455d5 100644
--- a/crypto/rand/rand_err.c
+++ b/crypto/rand/rand_err.c
@@ -44,6 +44,7 @@ static const ERR_STRING_DATA RAND_str_functs[] = {
{ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_ADD_BEGIN, 0),
"rand_pool_add_begin"},
{ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_ADD_END, 0), "rand_pool_add_end"},
+ {ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_ATTACH, 0), "rand_pool_attach"},
{ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_BYTES_NEEDED, 0),
"rand_pool_bytes_needed"},
{ERR_PACK(ERR_LIB_RAND, RAND_F_RAND_POOL_NEW, 0), "rand_pool_new"},
diff --git a/crypto/rand/rand_lcl.h b/crypto/rand/rand_lcl.h
index 7b1c74d4b3..13f8cc8239 100644
--- a/crypto/rand/rand_lcl.h
+++ b/crypto/rand/rand_lcl.h
@@ -32,18 +32,42 @@
-/* Max size of additional input and personalization string. */
-# define DRBG_MAX_LENGTH 4096
+/*
+ * Maximum input size for the DRBG (entropy, nonce, personalization string)
+ *
+ * NIST SP800 90Ar1 allows a maximum of (1 << 35) bits i.e., (1 << 32) bytes.
+ *
+ * We lower it to 'only' INT32_MAX bytes, which is equivalent to 2 gigabytes.
+ */
+# define DRBG_MAX_LENGTH INT32_MAX
+
+
/*
- * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
+ * Maximum allocation size for RANDOM_POOL buffers
*
- * The current factor is large enough that the RAND_POOL can store a
- * random input which has a lousy entropy rate of 0.0625 bits per byte.
- * This input will be sent through the derivation function which 'compresses'
- * the low quality input into a high quality output.
+ * The max_len value for the buffer provided to the rand_drbg_get_entropy()
+ * callback is currently 2^31 bytes (2 gigabytes), if a derivation function
+ * is used. Since this is much too large to be allocated, the rand_pool_new()
+ * function chooses more modest values as default pool length, bounded
+ * by RAND_POOL_MIN_LENGTH and RAND_POOL_MAX_LENGTH
+ *
+ * The choice of the RAND_POOL_FACTOR is large enough such that the
+ * RAND_POOL can store a random input which has a lousy entropy rate of
+ * 8/256 (= 0.03125) bits per byte. This input will be sent through the
+ * derivation function which 'compresses' the low quality input into a
+ * high quality output.
+ *
+ * The factor 1.5 below is the pessimistic estimate for the extra amount
+ * of entropy required when no get_nonce() callback is defined.
+ */
+# define RAND_POOL_FACTOR 256
+# define RAND_POOL_MAX_LENGTH (RAND_POOL_FACTOR * \
+ 3 * (RAND_DRBG_STRENGTH / 16))
+/*
+ * = (RAND_POOL_FACTOR * \
+ * 1.5 * (RAND_DRBG_STRENGTH / 8))
*/
-# define DRBG_MINMAX_FACTOR 128
/* DRBG status values */
@@ -142,10 +166,12 @@ struct rand_pool_st {
unsigned char *buffer; /* points to the beginning of the random pool */
size_t len; /* current number of random bytes contained in the pool */
+ int attached; /* true pool was attached to existing buffer */
+
size_t min_len; /* minimum number of random bytes requested */
size_t max_len; /* maximum number of random bytes (allocated buffer size) */
size_t entropy; /* current entropy count in bits */
- size_t requested_entropy; /* requested entropy count in bits */
+ size_t entropy_requested; /* requested entropy count in bits */
};
/*
@@ -167,7 +193,7 @@ struct rand_drbg_st {
unsigned short flags; /* various external flags */
/*
- * The random pool is used by RAND_add()/drbg_add() to attach random
+ * The random_data is used by RAND_add()/drbg_add() to attach random
* data to the global drbg, such that the rand_drbg_get_entropy() callback
* can pull it during instantiation and reseeding. This is necessary to
* reconcile the different philosophies of the RAND and the RAND_DRBG
diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index e9bc952210..f40c513ce8 100644
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -146,17 +146,11 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
return 0;
}
- pool = rand_pool_new(entropy, min_len, max_len);
- if (pool == NULL)
- return 0;
-
- if (drbg->pool) {
- rand_pool_add(pool,
- rand_pool_buffer(drbg->pool),
- rand_pool_length(drbg->pool),
- rand_pool_entropy(drbg->pool));
- rand_pool_free(drbg->pool);
- drbg->pool = NULL;
+ if (drbg->pool != NULL) {
+ pool = drbg->pool;
+ pool->entropy_requested = entropy;
+ } else {
+ pool = rand_pool_new(entropy, min_len, max_len);
}
if (drbg->parent) {
@@ -217,7 +211,10 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen)
{
- OPENSSL_secure_clear_free(out, outlen);
+ if (drbg->pool == NULL)
+ OPENSSL_secure_clear_free(out, outlen);
+ else
+ drbg->pool = NULL;
}
@@ -405,7 +402,7 @@ int RAND_poll(void)
/* fill random pool and seed the current legacy RNG */
pool = rand_pool_new(RAND_DRBG_STRENGTH,
RAND_DRBG_STRENGTH / 8,
- DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8));
+ RAND_POOL_MAX_LENGTH);
if (pool == NULL)
return 0;
@@ -430,17 +427,18 @@ err:
* Allocate memory and initialize a new random pool
*/
-RAND_POOL *rand_pool_new(int entropy, size_t min_len, size_t max_len)
+RAND_POOL *rand_pool_new(int entropy_requested, size_t min_len, size_t max_len)
{
RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
if (pool == NULL) {
RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
- goto err;
+ return NULL;
}
pool->min_len = min_len;
- pool->max_len = max_len;
+ pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
+ RAND_POOL_MAX_LENGTH : max_len;
pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
if (pool->buffer == NULL) {
@@ -448,7 +446,7 @@ RAND_POOL *rand_pool_new(int entropy, size_t min_len, size_t max_len)
goto err;
}
- pool->requested_entropy = entropy;
+ pool->entropy_requested = entropy_requested;
return pool;
@@ -458,6 +456,38 @@ err:
}
/*
+ * Attach new random pool to the given buffer
+ *
+ * This function is intended to be used only for feeding random data
+ * provided by RAND_add() and RAND_seed() into the <master> DRBG.
+ */
+RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
+ size_t entropy)
+{
+ RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
+
+ if (pool == NULL) {
+ RANDerr(RAND_F_RAND_POOL_ATTACH, ERR_R_MALLOC_FAILURE);
+ return NULL;
+ }
+
+ /*
+ * The const needs to be cast away, but attached buffers will not be
+ * modified (in contrary to allocated buffers which are zeroed and
+ * freed in the end).
+ */
+ pool->buffer = (unsigned char *) buffer;
+ pool->len = len;
+
+ pool->attached = 1;
+
+ pool->min_len = pool->max_len = pool->len;
+ pool->entropy = entropy;
+
+ return pool;
+}
+
+/*
* Free |pool|, securely erasing its buffer.
*/
void rand_pool_free(RAND_POOL *pool)
@@ -465,7 +495,14 @@ void rand_pool_free(RAND_POOL *pool)
if (pool == NULL)
return;
- OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
+ /*
+ * Although it would be advisable from a cryptographical viewpoint,
+ * we are not allowed to clear attached buffers, since they are passed
+ * to rand_pool_attach() as `const unsigned char*`.
+ * (see corresponding comment in rand_pool_attach()).
+ */
+ if (!pool->attached)
+ OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
OPENSSL_free(pool);
}
@@ -524,7 +561,7 @@ unsigned char *rand_pool_detach(RAND_POOL *pool)
*/
size_t rand_pool_entropy_available(RAND_POOL *pool)
{
- if (pool->entropy < pool->requested_entropy)
+ if (pool->entropy < pool->entropy_requested)
return 0;
if (pool->len < pool->min_len)
@@ -540,8 +577,8 @@ size_t rand_pool_entropy_available(RAND_POOL *pool)
size_t rand_pool_entropy_needed(RAND_POOL *pool)
{
- if (pool->entropy < pool->requested_entropy)
- return pool->requested_entropy - pool->entropy;
+ if (pool->entropy < pool->entropy_requested)
+ return pool->entropy_requested - pool->entropy;
return 0;
}
diff --git a/crypto/rand/rand_unix.c b/crypto/rand/rand_unix.c
index e53b876dd3..cb3a6b24ab 100644
--- a/crypto/rand/rand_unix.c
+++ b/crypto/rand/rand_unix.c
@@ -264,7 +264,7 @@ static ssize_t syscall_random(void *buf, size_t buflen)
* Note: 'buflen' equals the size of the buffer which is used by the
* get_entropy() callback of the RAND_DRBG. It is roughly bounded by
*
- * 2 * DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^13
+ * 2 * RAND_POOL_FACTOR * (RAND_DRBG_STRENGTH / 8) = 2^14
*
* which is way below the OSSL_SSIZE_MAX limit. Therefore sign conversion
* between size_t and ssize_t is safe even without a range check.
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 20:41:22 +0100