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Add support for PBKDF2 for enc command

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Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2083)
This commit is contained in:
EasySec 2016-12-14 16:29:06 +01:00 committed by Matt Caswell
parent 59053968e7
commit 405988f2cc
2 changed files with 60 additions and 12 deletions
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58
apps/enc.c
View file

@ -44,7 +44,7 @@ typedef enum OPTION_choice {
OPT_E, OPT_IN, OPT_OUT, OPT_PASS, OPT_ENGINE, OPT_D, OPT_P, OPT_V,
OPT_NOPAD, OPT_SALT, OPT_NOSALT, OPT_DEBUG, OPT_UPPER_P, OPT_UPPER_A,
OPT_A, OPT_Z, OPT_BUFSIZE, OPT_K, OPT_KFILE, OPT_UPPER_K, OPT_NONE,
OPT_UPPER_S, OPT_IV, OPT_MD, OPT_CIPHER,
OPT_UPPER_S, OPT_IV, OPT_MD, OPT_ITER, OPT_PBKDF2, OPT_CIPHER,
OPT_R_ENUM
} OPTION_CHOICE;
@ -74,6 +74,8 @@ const OPTIONS enc_options[] = {
{"S", OPT_UPPER_S, 's', "Salt, in hex"},
{"iv", OPT_IV, 's', "IV in hex"},
{"md", OPT_MD, 's', "Use specified digest to create a key from the passphrase"},
{"iter", OPT_ITER, 'p', "Specify the iteration count and force use of PBKDF2"},
{"pbkdf2", OPT_PBKDF2, '-', "Use password-based key derivation function 2"},
{"none", OPT_NONE, '-', "Don't encrypt"},
{"", OPT_CIPHER, '-', "Any supported cipher"},
OPT_R_OPTIONS,
@ -107,6 +109,8 @@ int enc_main(int argc, char **argv)
int ret = 1, inl, nopad = 0;
unsigned char key[EVP_MAX_KEY_LENGTH], iv[EVP_MAX_IV_LENGTH];
unsigned char *buff = NULL, salt[PKCS5_SALT_LEN];
int pbkdf2 = 0;
int iter = 0;
long n;
struct doall_enc_ciphers dec;
#ifdef ZLIB
@ -255,6 +259,16 @@ int enc_main(int argc, char **argv)
goto opthelp;
cipher = c;
break;
case OPT_ITER:
if (!opt_int(opt_arg(), &iter))
goto opthelp;
pbkdf2 = 1;
break;
case OPT_PBKDF2:
pbkdf2 = 1;
if (iter == 0) /* do not overwrite a chosen value */
iter = 10000;
break;
case OPT_NONE:
cipher = NULL;
break;
@ -282,6 +296,9 @@ int enc_main(int argc, char **argv)
if (dgst == NULL)
dgst = EVP_sha256();
if (iter == 0)
iter = 1;
/* It must be large enough for a base64 encoded line */
if (base64 && bsize < 80)
bsize = 80;
@ -439,15 +456,37 @@ int enc_main(int argc, char **argv)
BIO_printf(bio_err, "bad magic number\n");
goto end;
}
sptr = salt;
}
if (!EVP_BytesToKey(cipher, dgst, sptr,
(unsigned char *)str,
str_len, 1, key, iv)) {
BIO_printf(bio_err, "EVP_BytesToKey failed\n");
goto end;
if (pbkdf2 == 1) {
/*
* derive key and default iv
* concatenated into a temporary buffer
*/
unsigned char tmpkeyiv[EVP_MAX_KEY_LENGTH + EVP_MAX_IV_LENGTH];
int iklen = EVP_CIPHER_key_length(cipher);
int ivlen = EVP_CIPHER_iv_length(cipher);
/* not needed if HASH_UPDATE() is fixed : */
int islen = (sptr != NULL ? sizeof(salt) : 0);
if (!PKCS5_PBKDF2_HMAC(str, str_len, sptr, islen,
iter, dgst, iklen+ivlen, tmpkeyiv)) {
BIO_printf(bio_err, "PKCS5_PBKDF2_HMAC failed\n");
goto end;
}
/* split and move data back to global buffer */
memcpy(key, tmpkeyiv, iklen);
memcpy(iv, tmpkeyiv+iklen, ivlen);
} else {
BIO_printf(bio_err, "*** WARNING : "
"deprecated key derivation used.\n"
"Using -iter or -pbkdf2 would be better.\n");
if (!EVP_BytesToKey(cipher, dgst, sptr,
(unsigned char *)str, str_len,
1, key, iv)) {
BIO_printf(bio_err, "EVP_BytesToKey failed\n");
goto end;
}
}
/*
* zero the complete buffer or the string passed from the command
@ -470,9 +509,8 @@ int enc_main(int argc, char **argv)
if ((hiv == NULL) && (str == NULL)
&& EVP_CIPHER_iv_length(cipher) != 0) {
/*
* No IV was explicitly set and no IV was generated during
* EVP_BytesToKey. Hence the IV is undefined, making correct
* decryption impossible.
* No IV was explicitly set and no IV was generated.
* Hence the IV is undefined, making correct decryption impossible.
*/
BIO_printf(bio_err, "iv undefined\n");
goto end;

14
doc/man1/enc.pod
View file

@ -27,6 +27,8 @@ B<openssl enc -I<cipher>>
[B<-nosalt>]
[B<-z>]
[B<-md digest>]
[B<-iter count>]
[B<-pbkdf2>]
[B<-p>]
[B<-P>]
[B<-bufsize number>]
@ -109,6 +111,16 @@ the B<-pass> argument.
Use the specified digest to create the key from the passphrase.
The default algorithm is sha-256.
=item B<-iter count>
Use a given number of iterations on the password in deriving the encryption key.
High values increase the time required to brute-force the resulting file.
This option enables the use of PBKDF2 algorithm to derive the key.
=item B<-pbkdf2>
Use PBKDF2 algorithm with default iteration count unless otherwise specified.
=item B<-nosalt>
Don't use a salt in the key derivation routines. This option B<SHOULD NOT> be
@ -375,8 +387,6 @@ Decrypt some data using a supplied 40 bit RC4 key:
The B<-A> option when used with large files doesn't work properly.
There should be an option to allow an iteration count to be included.
The B<enc> program only supports a fixed number of algorithms with
certain parameters. So if, for example, you want to use RC2 with a
76 bit key or RC4 with an 84 bit key you can't use this program.