version 1.51, 2014/02/02 03:44:31 |
version 1.52, 2014/06/24 01:13:21 |
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#include <string.h> |
#include <string.h> |
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#include "xmalloc.h" |
#include "sshbuf.h" |
#include "log.h" |
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#include "buffer.h" |
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#include "key.h" |
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#include "compat.h" |
#include "compat.h" |
#include "misc.h" |
#include "ssherr.h" |
#include "ssh.h" |
#define SSHKEY_INTERNAL |
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#include "sshkey.h" |
#include "digest.h" |
#include "digest.h" |
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static int openssh_RSA_verify(int, u_char *, u_int, u_char *, u_int, RSA *); |
static int openssh_RSA_verify(int, u_char *, size_t, u_char *, size_t, RSA *); |
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/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */ |
/* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */ |
int |
int |
ssh_rsa_sign(const Key *key, u_char **sigp, u_int *lenp, |
ssh_rsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp, |
const u_char *data, u_int datalen) |
const u_char *data, size_t datalen, u_int compat) |
{ |
{ |
int hash_alg; |
int hash_alg; |
u_char digest[SSH_DIGEST_MAX_LENGTH], *sig; |
u_char digest[SSH_DIGEST_MAX_LENGTH], *sig = NULL; |
u_int slen, dlen, len; |
size_t slen; |
int ok, nid; |
u_int dlen, len; |
Buffer b; |
int nid, ret = SSH_ERR_INTERNAL_ERROR; |
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struct sshbuf *b = NULL; |
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if (key == NULL || key_type_plain(key->type) != KEY_RSA || |
if (lenp != NULL) |
key->rsa == NULL) { |
*lenp = 0; |
error("%s: no RSA key", __func__); |
if (sigp != NULL) |
return -1; |
*sigp = NULL; |
} |
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if (key == NULL || key->rsa == NULL || |
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sshkey_type_plain(key->type) != KEY_RSA) |
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return SSH_ERR_INVALID_ARGUMENT; |
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slen = RSA_size(key->rsa); |
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if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM) |
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return SSH_ERR_INVALID_ARGUMENT; |
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/* hash the data */ |
/* hash the data */ |
hash_alg = SSH_DIGEST_SHA1; |
hash_alg = SSH_DIGEST_SHA1; |
nid = NID_sha1; |
nid = NID_sha1; |
if ((dlen = ssh_digest_bytes(hash_alg)) == 0) { |
if ((dlen = ssh_digest_bytes(hash_alg)) == 0) |
error("%s: bad hash algorithm %d", __func__, hash_alg); |
return SSH_ERR_INTERNAL_ERROR; |
return -1; |
if ((ret = ssh_digest_memory(hash_alg, data, datalen, |
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digest, sizeof(digest))) != 0) |
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goto out; |
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if ((sig = malloc(slen)) == NULL) { |
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ret = SSH_ERR_ALLOC_FAIL; |
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goto out; |
} |
} |
if (ssh_digest_memory(hash_alg, data, datalen, |
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digest, sizeof(digest)) != 0) { |
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error("%s: ssh_digest_memory failed", __func__); |
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return -1; |
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} |
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slen = RSA_size(key->rsa); |
if (RSA_sign(nid, digest, dlen, sig, &len, key->rsa) != 1) { |
sig = xmalloc(slen); |
ret = SSH_ERR_LIBCRYPTO_ERROR; |
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goto out; |
ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa); |
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explicit_bzero(digest, sizeof(digest)); |
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if (ok != 1) { |
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int ecode = ERR_get_error(); |
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error("%s: RSA_sign failed: %s", __func__, |
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ERR_error_string(ecode, NULL)); |
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free(sig); |
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return -1; |
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} |
} |
if (len < slen) { |
if (len < slen) { |
u_int diff = slen - len; |
size_t diff = slen - len; |
debug("slen %u > len %u", slen, len); |
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memmove(sig + diff, sig, len); |
memmove(sig + diff, sig, len); |
explicit_bzero(sig, diff); |
explicit_bzero(sig, diff); |
} else if (len > slen) { |
} else if (len > slen) { |
error("%s: slen %u slen2 %u", __func__, slen, len); |
ret = SSH_ERR_INTERNAL_ERROR; |
free(sig); |
goto out; |
return -1; |
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} |
} |
/* encode signature */ |
/* encode signature */ |
buffer_init(&b); |
if ((b = sshbuf_new()) == NULL) { |
buffer_put_cstring(&b, "ssh-rsa"); |
ret = SSH_ERR_ALLOC_FAIL; |
buffer_put_string(&b, sig, slen); |
goto out; |
len = buffer_len(&b); |
} |
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if ((ret = sshbuf_put_cstring(b, "ssh-rsa")) != 0 || |
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(ret = sshbuf_put_string(b, sig, slen)) != 0) |
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goto out; |
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len = sshbuf_len(b); |
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if (sigp != NULL) { |
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if ((*sigp = malloc(len)) == NULL) { |
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ret = SSH_ERR_ALLOC_FAIL; |
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goto out; |
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} |
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memcpy(*sigp, sshbuf_ptr(b), len); |
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} |
if (lenp != NULL) |
if (lenp != NULL) |
*lenp = len; |
*lenp = len; |
if (sigp != NULL) { |
ret = 0; |
*sigp = xmalloc(len); |
out: |
memcpy(*sigp, buffer_ptr(&b), len); |
explicit_bzero(digest, sizeof(digest)); |
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if (sig != NULL) { |
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explicit_bzero(sig, slen); |
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free(sig); |
} |
} |
buffer_free(&b); |
if (b != NULL) |
explicit_bzero(sig, slen); |
sshbuf_free(b); |
free(sig); |
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return 0; |
return 0; |
} |
} |
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int |
int |
ssh_rsa_verify(const Key *key, const u_char *signature, u_int signaturelen, |
ssh_rsa_verify(const struct sshkey *key, |
const u_char *data, u_int datalen) |
const u_char *signature, size_t signaturelen, |
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const u_char *data, size_t datalen, u_int compat) |
{ |
{ |
Buffer b; |
char *ktype = NULL; |
int hash_alg; |
int hash_alg, ret = SSH_ERR_INTERNAL_ERROR; |
char *ktype; |
size_t len, diff, modlen, dlen; |
u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob; |
struct sshbuf *b = NULL; |
u_int len, dlen, modlen; |
u_char digest[SSH_DIGEST_MAX_LENGTH], *osigblob, *sigblob = NULL; |
int rlen, ret; |
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if (key == NULL || key_type_plain(key->type) != KEY_RSA || |
if (key == NULL || key->rsa == NULL || |
key->rsa == NULL) { |
sshkey_type_plain(key->type) != KEY_RSA || |
error("%s: no RSA key", __func__); |
BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) |
return -1; |
return SSH_ERR_INVALID_ARGUMENT; |
} |
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if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) { |
if ((b = sshbuf_from(signature, signaturelen)) == NULL) |
error("%s: RSA modulus too small: %d < minimum %d bits", |
return SSH_ERR_ALLOC_FAIL; |
__func__, BN_num_bits(key->rsa->n), |
if (sshbuf_get_cstring(b, &ktype, NULL) != 0) { |
SSH_RSA_MINIMUM_MODULUS_SIZE); |
ret = SSH_ERR_INVALID_FORMAT; |
return -1; |
goto out; |
} |
} |
buffer_init(&b); |
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buffer_append(&b, signature, signaturelen); |
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ktype = buffer_get_cstring(&b, NULL); |
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if (strcmp("ssh-rsa", ktype) != 0) { |
if (strcmp("ssh-rsa", ktype) != 0) { |
error("%s: cannot handle type %s", __func__, ktype); |
ret = SSH_ERR_KEY_TYPE_MISMATCH; |
buffer_free(&b); |
goto out; |
free(ktype); |
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return -1; |
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} |
} |
free(ktype); |
if (sshbuf_get_string(b, &sigblob, &len) != 0) { |
sigblob = buffer_get_string(&b, &len); |
ret = SSH_ERR_INVALID_FORMAT; |
rlen = buffer_len(&b); |
goto out; |
buffer_free(&b); |
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if (rlen != 0) { |
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error("%s: remaining bytes in signature %d", __func__, rlen); |
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free(sigblob); |
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return -1; |
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} |
} |
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if (sshbuf_len(b) != 0) { |
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ret = SSH_ERR_UNEXPECTED_TRAILING_DATA; |
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goto out; |
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} |
/* RSA_verify expects a signature of RSA_size */ |
/* RSA_verify expects a signature of RSA_size */ |
modlen = RSA_size(key->rsa); |
modlen = RSA_size(key->rsa); |
if (len > modlen) { |
if (len > modlen) { |
error("%s: len %u > modlen %u", __func__, len, modlen); |
ret = SSH_ERR_KEY_BITS_MISMATCH; |
free(sigblob); |
goto out; |
return -1; |
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} else if (len < modlen) { |
} else if (len < modlen) { |
u_int diff = modlen - len; |
diff = modlen - len; |
debug("%s: add padding: modlen %u > len %u", __func__, |
osigblob = sigblob; |
modlen, len); |
if ((sigblob = realloc(sigblob, modlen)) == NULL) { |
sigblob = xrealloc(sigblob, 1, modlen); |
sigblob = osigblob; /* put it back for clear/free */ |
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ret = SSH_ERR_ALLOC_FAIL; |
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goto out; |
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} |
memmove(sigblob + diff, sigblob, len); |
memmove(sigblob + diff, sigblob, len); |
explicit_bzero(sigblob, diff); |
explicit_bzero(sigblob, diff); |
len = modlen; |
len = modlen; |
} |
} |
/* hash the data */ |
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hash_alg = SSH_DIGEST_SHA1; |
hash_alg = SSH_DIGEST_SHA1; |
if ((dlen = ssh_digest_bytes(hash_alg)) == 0) { |
if ((dlen = ssh_digest_bytes(hash_alg)) == 0) { |
error("%s: bad hash algorithm %d", __func__, hash_alg); |
ret = SSH_ERR_INTERNAL_ERROR; |
return -1; |
goto out; |
} |
} |
if (ssh_digest_memory(hash_alg, data, datalen, |
if ((ret = ssh_digest_memory(hash_alg, data, datalen, |
digest, sizeof(digest)) != 0) { |
digest, sizeof(digest))) != 0) |
error("%s: ssh_digest_memory failed", __func__); |
goto out; |
return -1; |
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} |
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ret = openssh_RSA_verify(hash_alg, digest, dlen, sigblob, len, |
ret = openssh_RSA_verify(hash_alg, digest, dlen, sigblob, len, |
key->rsa); |
key->rsa); |
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out: |
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if (sigblob != NULL) { |
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explicit_bzero(sigblob, len); |
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free(sigblob); |
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} |
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if (ktype != NULL) |
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free(ktype); |
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if (b != NULL) |
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sshbuf_free(b); |
explicit_bzero(digest, sizeof(digest)); |
explicit_bzero(digest, sizeof(digest)); |
explicit_bzero(sigblob, len); |
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free(sigblob); |
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debug("%s: signature %scorrect", __func__, (ret == 0) ? "in" : ""); |
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return ret; |
return ret; |
} |
} |
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}; |
}; |
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static int |
static int |
openssh_RSA_verify(int hash_alg, u_char *hash, u_int hashlen, |
openssh_RSA_verify(int hash_alg, u_char *hash, size_t hashlen, |
u_char *sigbuf, u_int siglen, RSA *rsa) |
u_char *sigbuf, size_t siglen, RSA *rsa) |
{ |
{ |
u_int ret, rsasize, oidlen = 0, hlen = 0; |
size_t ret, rsasize = 0, oidlen = 0, hlen = 0; |
int len, oidmatch, hashmatch; |
int len, oidmatch, hashmatch; |
const u_char *oid = NULL; |
const u_char *oid = NULL; |
u_char *decrypted = NULL; |
u_char *decrypted = NULL; |
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ret = 0; |
ret = SSH_ERR_INTERNAL_ERROR; |
switch (hash_alg) { |
switch (hash_alg) { |
case SSH_DIGEST_SHA1: |
case SSH_DIGEST_SHA1: |
oid = id_sha1; |
oid = id_sha1; |
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goto done; |
goto done; |
} |
} |
if (hashlen != hlen) { |
if (hashlen != hlen) { |
error("bad hashlen"); |
ret = SSH_ERR_INVALID_ARGUMENT; |
goto done; |
goto done; |
} |
} |
rsasize = RSA_size(rsa); |
rsasize = RSA_size(rsa); |
if (siglen == 0 || siglen > rsasize) { |
if (rsasize <= 0 || rsasize > SSHBUF_MAX_BIGNUM || |
error("bad siglen"); |
siglen == 0 || siglen > rsasize) { |
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ret = SSH_ERR_INVALID_ARGUMENT; |
goto done; |
goto done; |
} |
} |
decrypted = xmalloc(rsasize); |
if ((decrypted = malloc(rsasize)) == NULL) { |
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ret = SSH_ERR_ALLOC_FAIL; |
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goto done; |
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} |
if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa, |
if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa, |
RSA_PKCS1_PADDING)) < 0) { |
RSA_PKCS1_PADDING)) < 0) { |
error("RSA_public_decrypt failed: %s", |
ret = SSH_ERR_LIBCRYPTO_ERROR; |
ERR_error_string(ERR_get_error(), NULL)); |
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goto done; |
goto done; |
} |
} |
if (len < 0 || (u_int)len != hlen + oidlen) { |
if (len < 0 || (size_t)len != hlen + oidlen) { |
error("bad decrypted len: %d != %d + %d", len, hlen, oidlen); |
ret = SSH_ERR_INVALID_FORMAT; |
goto done; |
goto done; |
} |
} |
oidmatch = timingsafe_bcmp(decrypted, oid, oidlen) == 0; |
oidmatch = timingsafe_bcmp(decrypted, oid, oidlen) == 0; |
hashmatch = timingsafe_bcmp(decrypted + oidlen, hash, hlen) == 0; |
hashmatch = timingsafe_bcmp(decrypted + oidlen, hash, hlen) == 0; |
if (!oidmatch) { |
if (!oidmatch || !hashmatch) { |
error("oid mismatch"); |
ret = SSH_ERR_SIGNATURE_INVALID; |
goto done; |
goto done; |
} |
} |
if (!hashmatch) { |
ret = 0; |
error("hash mismatch"); |
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goto done; |
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} |
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ret = 1; |
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done: |
done: |
free(decrypted); |
if (decrypted) { |
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explicit_bzero(decrypted, rsasize); |
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free(decrypted); |
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} |
return ret; |
return ret; |
} |
} |