version 1.10, 2001/09/17 19:27:15 |
version 1.10.2.6, 2002/10/11 14:53:07 |
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#include "key.h" |
#include "key.h" |
#include "ssh-rsa.h" |
#include "ssh-rsa.h" |
#include "compat.h" |
#include "compat.h" |
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#include "ssh.h" |
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static int openssh_RSA_verify(int, u_char *, u_int, u_char *, u_int , 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( |
ssh_rsa_sign(Key *key, u_char **sigp, u_int *lenp, |
Key *key, |
u_char *data, u_int datalen) |
u_char **sigp, int *lenp, |
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u_char *data, int datalen) |
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{ |
{ |
const EVP_MD *evp_md; |
const EVP_MD *evp_md; |
EVP_MD_CTX md; |
EVP_MD_CTX md; |
u_char *digest, *sig, *ret; |
u_char digest[EVP_MAX_MD_SIZE], *sig; |
u_int slen, dlen, len; |
u_int slen, dlen, len; |
int ok, nid; |
int ok, nid; |
Buffer b; |
Buffer b; |
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error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid); |
error("ssh_rsa_sign: EVP_get_digestbynid %d failed", nid); |
return -1; |
return -1; |
} |
} |
dlen = evp_md->md_size; |
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digest = xmalloc(dlen); |
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EVP_DigestInit(&md, evp_md); |
EVP_DigestInit(&md, evp_md); |
EVP_DigestUpdate(&md, data, datalen); |
EVP_DigestUpdate(&md, data, datalen); |
EVP_DigestFinal(&md, digest, NULL); |
EVP_DigestFinal(&md, digest, &dlen); |
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slen = RSA_size(key->rsa); |
slen = RSA_size(key->rsa); |
sig = xmalloc(slen); |
sig = xmalloc(slen); |
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ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa); |
ok = RSA_sign(nid, digest, dlen, sig, &len, key->rsa); |
memset(digest, 'd', dlen); |
memset(digest, 'd', sizeof(digest)); |
xfree(digest); |
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if (ok != 1) { |
if (ok != 1) { |
int ecode = ERR_get_error(); |
int ecode = ERR_get_error(); |
error("ssh_rsa_sign: RSA_sign failed: %s", ERR_error_string(ecode, NULL)); |
error("ssh_rsa_sign: RSA_sign failed: %s", |
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ERR_error_string(ecode, NULL)); |
xfree(sig); |
xfree(sig); |
return -1; |
return -1; |
} |
} |
if (len < slen) { |
if (len < slen) { |
int diff = slen - len; |
u_int diff = slen - len; |
debug("slen %d > len %d", slen, len); |
debug("slen %u > len %u", slen, len); |
memmove(sig + diff, sig, len); |
memmove(sig + diff, sig, len); |
memset(sig, 0, diff); |
memset(sig, 0, diff); |
} else if (len > slen) { |
} else if (len > slen) { |
error("ssh_rsa_sign: slen %d slen2 %d", slen, len); |
error("ssh_rsa_sign: slen %u slen2 %u", slen, len); |
xfree(sig); |
xfree(sig); |
return -1; |
return -1; |
} |
} |
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buffer_put_cstring(&b, "ssh-rsa"); |
buffer_put_cstring(&b, "ssh-rsa"); |
buffer_put_string(&b, sig, slen); |
buffer_put_string(&b, sig, slen); |
len = buffer_len(&b); |
len = buffer_len(&b); |
ret = xmalloc(len); |
if (lenp != NULL) |
memcpy(ret, buffer_ptr(&b), len); |
*lenp = len; |
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if (sigp != NULL) { |
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*sigp = xmalloc(len); |
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memcpy(*sigp, buffer_ptr(&b), len); |
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} |
buffer_free(&b); |
buffer_free(&b); |
memset(sig, 's', slen); |
memset(sig, 's', slen); |
xfree(sig); |
xfree(sig); |
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if (lenp != NULL) |
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*lenp = len; |
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if (sigp != NULL) |
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*sigp = ret; |
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return 0; |
return 0; |
} |
} |
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int |
int |
ssh_rsa_verify( |
ssh_rsa_verify(Key *key, u_char *signature, u_int signaturelen, |
Key *key, |
u_char *data, u_int datalen) |
u_char *signature, int signaturelen, |
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u_char *data, int datalen) |
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{ |
{ |
Buffer b; |
Buffer b; |
const EVP_MD *evp_md; |
const EVP_MD *evp_md; |
EVP_MD_CTX md; |
EVP_MD_CTX md; |
char *ktype; |
char *ktype; |
u_char *sigblob, *digest; |
u_char digest[EVP_MAX_MD_SIZE], *sigblob; |
u_int len, dlen; |
u_int len, dlen, modlen; |
int rlen, ret, nid; |
int rlen, ret, nid; |
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if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) { |
if (key == NULL || key->type != KEY_RSA || key->rsa == NULL) { |
error("ssh_rsa_verify: no RSA key"); |
error("ssh_rsa_verify: no RSA key"); |
return -1; |
return -1; |
} |
} |
if (BN_num_bits(key->rsa->n) < 768) { |
if (BN_num_bits(key->rsa->n) < SSH_RSA_MINIMUM_MODULUS_SIZE) { |
error("ssh_rsa_verify: n too small: %d bits", |
error("ssh_rsa_verify: RSA modulus too small: %d < minimum %d bits", |
BN_num_bits(key->rsa->n)); |
BN_num_bits(key->rsa->n), SSH_RSA_MINIMUM_MODULUS_SIZE); |
return -1; |
return -1; |
} |
} |
buffer_init(&b); |
buffer_init(&b); |
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sigblob = buffer_get_string(&b, &len); |
sigblob = buffer_get_string(&b, &len); |
rlen = buffer_len(&b); |
rlen = buffer_len(&b); |
buffer_free(&b); |
buffer_free(&b); |
if(rlen != 0) { |
if (rlen != 0) { |
xfree(sigblob); |
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error("ssh_rsa_verify: remaining bytes in signature %d", rlen); |
error("ssh_rsa_verify: remaining bytes in signature %d", rlen); |
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xfree(sigblob); |
return -1; |
return -1; |
} |
} |
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/* RSA_verify expects a signature of RSA_size */ |
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modlen = RSA_size(key->rsa); |
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if (len > modlen) { |
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error("ssh_rsa_verify: len %u > modlen %u", len, modlen); |
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xfree(sigblob); |
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return -1; |
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} else if (len < modlen) { |
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u_int diff = modlen - len; |
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debug("ssh_rsa_verify: add padding: modlen %u > len %u", |
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modlen, len); |
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sigblob = xrealloc(sigblob, modlen); |
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memmove(sigblob + diff, sigblob, len); |
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memset(sigblob, 0, diff); |
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len = modlen; |
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} |
nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1; |
nid = (datafellows & SSH_BUG_RSASIGMD5) ? NID_md5 : NID_sha1; |
if ((evp_md = EVP_get_digestbynid(nid)) == NULL) { |
if ((evp_md = EVP_get_digestbynid(nid)) == NULL) { |
xfree(sigblob); |
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error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid); |
error("ssh_rsa_verify: EVP_get_digestbynid %d failed", nid); |
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xfree(sigblob); |
return -1; |
return -1; |
} |
} |
dlen = evp_md->md_size; |
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digest = xmalloc(dlen); |
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EVP_DigestInit(&md, evp_md); |
EVP_DigestInit(&md, evp_md); |
EVP_DigestUpdate(&md, data, datalen); |
EVP_DigestUpdate(&md, data, datalen); |
EVP_DigestFinal(&md, digest, NULL); |
EVP_DigestFinal(&md, digest, &dlen); |
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ret = RSA_verify(nid, digest, dlen, sigblob, len, key->rsa); |
ret = openssh_RSA_verify(nid, digest, dlen, sigblob, len, key->rsa); |
memset(digest, 'd', dlen); |
memset(digest, 'd', sizeof(digest)); |
xfree(digest); |
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memset(sigblob, 's', len); |
memset(sigblob, 's', len); |
xfree(sigblob); |
xfree(sigblob); |
if (ret == 0) { |
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int ecode = ERR_get_error(); |
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error("ssh_rsa_verify: RSA_verify failed: %s", ERR_error_string(ecode, NULL)); |
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} |
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debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : ""); |
debug("ssh_rsa_verify: signature %scorrect", (ret==0) ? "in" : ""); |
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return ret; |
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} |
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/* |
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* See: |
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* http://www.rsasecurity.com/rsalabs/pkcs/pkcs-1/ |
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* ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.asn |
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*/ |
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/* |
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* id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) |
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* oiw(14) secsig(3) algorithms(2) 26 } |
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*/ |
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static const u_char id_sha1[] = { |
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0x30, 0x21, /* type Sequence, length 0x21 (33) */ |
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0x30, 0x09, /* type Sequence, length 0x09 */ |
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0x06, 0x05, /* type OID, length 0x05 */ |
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0x2b, 0x0e, 0x03, 0x02, 0x1a, /* id-sha1 OID */ |
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0x05, 0x00, /* NULL */ |
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0x04, 0x14 /* Octet string, length 0x14 (20), followed by sha1 hash */ |
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}; |
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/* |
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* id-md5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) |
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* rsadsi(113549) digestAlgorithm(2) 5 } |
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*/ |
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static const u_char id_md5[] = { |
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0x30, 0x20, /* type Sequence, length 0x20 (32) */ |
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0x30, 0x0c, /* type Sequence, length 0x09 */ |
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0x06, 0x08, /* type OID, length 0x05 */ |
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0x2a, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* id-md5 */ |
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0x05, 0x00, /* NULL */ |
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0x04, 0x10 /* Octet string, length 0x10 (16), followed by md5 hash */ |
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}; |
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static int |
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openssh_RSA_verify(int type, u_char *hash, u_int hashlen, |
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u_char *sigbuf, u_int siglen, RSA *rsa) |
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{ |
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u_int ret, rsasize, oidlen = 0, hlen = 0; |
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int len; |
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const u_char *oid = NULL; |
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u_char *decrypted = NULL; |
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ret = 0; |
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switch (type) { |
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case NID_sha1: |
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oid = id_sha1; |
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oidlen = sizeof(id_sha1); |
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hlen = 20; |
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break; |
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case NID_md5: |
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oid = id_md5; |
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oidlen = sizeof(id_md5); |
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hlen = 16; |
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break; |
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default: |
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goto done; |
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break; |
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} |
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if (hashlen != hlen) { |
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error("bad hashlen"); |
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goto done; |
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} |
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rsasize = RSA_size(rsa); |
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if (siglen == 0 || siglen > rsasize) { |
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error("bad siglen"); |
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goto done; |
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} |
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decrypted = xmalloc(rsasize); |
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if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa, |
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RSA_PKCS1_PADDING)) < 0) { |
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error("RSA_public_decrypt failed: %s", |
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ERR_error_string(ERR_get_error(), NULL)); |
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goto done; |
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} |
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if (len != hlen + oidlen) { |
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error("bad decrypted len: %d != %d + %d", len, hlen, oidlen); |
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goto done; |
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} |
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if (memcmp(decrypted, oid, oidlen) != 0) { |
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error("oid mismatch"); |
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goto done; |
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} |
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if (memcmp(decrypted + oidlen, hash, hlen) != 0) { |
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error("hash mismatch"); |
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goto done; |
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} |
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ret = 1; |
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done: |
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if (decrypted) |
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xfree(decrypted); |
return ret; |
return ret; |
} |
} |