Commit 720b3598 authored by Bodo Möller's avatar Bodo Möller
Browse files

Avoid integer overflow in entropy counter. 

Slightly clarify the RAND_... documentation.
parent 60b52453

crypto/rand/md_rand.c

+3 −2
Original line number Diff line number Diff line
@@ -138,7 +138,7 @@ static int state_num=0,state_index=0; 
static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];

static unsigned char md[MD_DIGEST_LENGTH];

static long md_count[2]={0,0};

static int entropy=0;

static unsigned entropy=0;



const char *RAND_version="RAND" OPENSSL_VERSION_PTEXT;
@@ -286,6 +286,7 @@ static void ssleay_rand_add(const void *buf, int num, int add) 
#ifndef THREADS	

	assert(md_c[1] == md_count[1]);

#endif

	if (entropy < ENTROPY_NEEDED)

	    entropy += add;

	}

doc/crypto/RAND_add.pod

+1 −1
Original line number Diff line number Diff line
@@ -30,7 +30,7 @@ RAND_add() may be called with sensitive data such as user entered 
passwords. The seed values cannot be recovered from the PRNG output.



OpenSSL makes sure that the PRNG state is unique for each thread. On

systems that provide C</dev/random>, the randomness device is used

systems that provide C</dev/urandom>, the randomness device is used

to seed the PRNG transparently. However, on all other systems, the

application is responsible for seeding the PRNG by calling RAND_add()

or RAND_load_file(3).

doc/crypto/RAND_bytes.pod

+10 −7
Original line number Diff line number Diff line
@@ -14,13 +14,16 @@ RAND_bytes, RAND_pseudo_bytes - Generate random data 


=head1 DESCRIPTION



RAND_bytes() puts B<num> random bytes into B<buf>. An error occurs if

the PRNG has not been seeded with enough randomness.



RAND_pseudo_bytes() puts B<num> pseudo-random bytes into B<buf>. These

bytes are guaranteed to be unique, but not unpredictable. They can be

used for non-cryptographic purposes and for certain purposes in

cryptographic protocols, but not for key generation etc.

RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes

into B<buf>. An error occurs if the PRNG has not been seeded with

enough randomness to ensure an unpredictable byte sequence.



RAND_pseudo_bytes() puts B<num> pseudo-random bytes into B<buf>.

Pseudo-random byte sequences generated by RAND_pseudo_bytes() will be

unique if they are of sufficient length, but are not necessarily

unpredictable. They can be used for non-cryptographic purposes and for

certain purposes in cryptographic protocols, but usually not for key

generation etc.



=head1 RETURN VALUES