aboutsummaryrefslogtreecommitdiff
path: root/openssl/ssl/t1_enc.c
diff options
context:
space:
mode:
Diffstat (limited to 'openssl/ssl/t1_enc.c')
-rw-r--r--openssl/ssl/t1_enc.c307
1 files changed, 258 insertions, 49 deletions
diff --git a/openssl/ssl/t1_enc.c b/openssl/ssl/t1_enc.c
index 793ea43e9..201ca9ad6 100644
--- a/openssl/ssl/t1_enc.c
+++ b/openssl/ssl/t1_enc.c
@@ -143,6 +143,7 @@
#include <openssl/evp.h>
#include <openssl/hmac.h>
#include <openssl/md5.h>
+#include <openssl/rand.h>
#ifdef KSSL_DEBUG
#include <openssl/des.h>
#endif
@@ -158,68 +159,75 @@ static int tls1_P_hash(const EVP_MD *md, const unsigned char *sec,
unsigned char *out, int olen)
{
int chunk;
- unsigned int j;
- HMAC_CTX ctx;
- HMAC_CTX ctx_tmp;
+ size_t j;
+ EVP_MD_CTX ctx, ctx_tmp;
+ EVP_PKEY *mac_key;
unsigned char A1[EVP_MAX_MD_SIZE];
- unsigned int A1_len;
+ size_t A1_len;
int ret = 0;
chunk=EVP_MD_size(md);
OPENSSL_assert(chunk >= 0);
- HMAC_CTX_init(&ctx);
- HMAC_CTX_init(&ctx_tmp);
- if (!HMAC_Init_ex(&ctx,sec,sec_len,md, NULL))
+ EVP_MD_CTX_init(&ctx);
+ EVP_MD_CTX_init(&ctx_tmp);
+ EVP_MD_CTX_set_flags(&ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
+ EVP_MD_CTX_set_flags(&ctx_tmp, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
+ mac_key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, sec, sec_len);
+ if (!mac_key)
+ goto err;
+ if (!EVP_DigestSignInit(&ctx,NULL,md, NULL, mac_key))
goto err;
- if (!HMAC_Init_ex(&ctx_tmp,sec,sec_len,md, NULL))
+ if (!EVP_DigestSignInit(&ctx_tmp,NULL,md, NULL, mac_key))
goto err;
- if (seed1 != NULL && !HMAC_Update(&ctx,seed1,seed1_len))
+ if (seed1 && !EVP_DigestSignUpdate(&ctx,seed1,seed1_len))
goto err;
- if (seed2 != NULL && !HMAC_Update(&ctx,seed2,seed2_len))
+ if (seed2 && !EVP_DigestSignUpdate(&ctx,seed2,seed2_len))
goto err;
- if (seed3 != NULL && !HMAC_Update(&ctx,seed3,seed3_len))
+ if (seed3 && !EVP_DigestSignUpdate(&ctx,seed3,seed3_len))
goto err;
- if (seed4 != NULL && !HMAC_Update(&ctx,seed4,seed4_len))
+ if (seed4 && !EVP_DigestSignUpdate(&ctx,seed4,seed4_len))
goto err;
- if (seed5 != NULL && !HMAC_Update(&ctx,seed5,seed5_len))
+ if (seed5 && !EVP_DigestSignUpdate(&ctx,seed5,seed5_len))
goto err;
- if (!HMAC_Final(&ctx,A1,&A1_len))
+ if (!EVP_DigestSignFinal(&ctx,A1,&A1_len))
goto err;
for (;;)
{
- if (!HMAC_Init_ex(&ctx,NULL,0,NULL,NULL)) /* re-init */
+ /* Reinit mac contexts */
+ if (!EVP_DigestSignInit(&ctx,NULL,md, NULL, mac_key))
goto err;
- if (!HMAC_Init_ex(&ctx_tmp,NULL,0,NULL,NULL)) /* re-init */
+ if (!EVP_DigestSignInit(&ctx_tmp,NULL,md, NULL, mac_key))
goto err;
- if (!HMAC_Update(&ctx,A1,A1_len))
+ if (!EVP_DigestSignUpdate(&ctx,A1,A1_len))
goto err;
- if (!HMAC_Update(&ctx_tmp,A1,A1_len))
+ if (!EVP_DigestSignUpdate(&ctx_tmp,A1,A1_len))
goto err;
- if (seed1 != NULL && !HMAC_Update(&ctx,seed1,seed1_len))
+ if (seed1 && !EVP_DigestSignUpdate(&ctx,seed1,seed1_len))
goto err;
- if (seed2 != NULL && !HMAC_Update(&ctx,seed2,seed2_len))
+ if (seed2 && !EVP_DigestSignUpdate(&ctx,seed2,seed2_len))
goto err;
- if (seed3 != NULL && !HMAC_Update(&ctx,seed3,seed3_len))
+ if (seed3 && !EVP_DigestSignUpdate(&ctx,seed3,seed3_len))
goto err;
- if (seed4 != NULL && !HMAC_Update(&ctx,seed4,seed4_len))
+ if (seed4 && !EVP_DigestSignUpdate(&ctx,seed4,seed4_len))
goto err;
- if (seed5 != NULL && !HMAC_Update(&ctx,seed5,seed5_len))
+ if (seed5 && !EVP_DigestSignUpdate(&ctx,seed5,seed5_len))
goto err;
if (olen > chunk)
{
- if (!HMAC_Final(&ctx,out,&j))
+ if (!EVP_DigestSignFinal(&ctx,out,&j))
goto err;
out+=j;
olen-=j;
- if (!HMAC_Final(&ctx_tmp,A1,&A1_len)) /* calc the next A1 value */
+ /* calc the next A1 value */
+ if (!EVP_DigestSignFinal(&ctx_tmp,A1,&A1_len))
goto err;
}
else /* last one */
{
- if (!HMAC_Final(&ctx,A1,&A1_len))
+ if (!EVP_DigestSignFinal(&ctx,A1,&A1_len))
goto err;
memcpy(out,A1,olen);
break;
@@ -227,8 +235,9 @@ static int tls1_P_hash(const EVP_MD *md, const unsigned char *sec,
}
ret = 1;
err:
- HMAC_CTX_cleanup(&ctx);
- HMAC_CTX_cleanup(&ctx_tmp);
+ EVP_PKEY_free(mac_key);
+ EVP_MD_CTX_cleanup(&ctx);
+ EVP_MD_CTX_cleanup(&ctx_tmp);
OPENSSL_cleanse(A1,sizeof(A1));
return ret;
}
@@ -256,6 +265,8 @@ static int tls1_PRF(long digest_mask,
if ((m<<TLS1_PRF_DGST_SHIFT) & digest_mask) count++;
}
len=slen/count;
+ if (count == 1)
+ slen = 0;
S1=sec;
memset(out1,0,olen);
for (idx=0;ssl_get_handshake_digest(idx,&m,&md);idx++) {
@@ -284,7 +295,7 @@ static int tls1_generate_key_block(SSL *s, unsigned char *km,
unsigned char *tmp, int num)
{
int ret;
- ret = tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+ ret = tls1_PRF(ssl_get_algorithm2(s),
TLS_MD_KEY_EXPANSION_CONST,TLS_MD_KEY_EXPANSION_CONST_SIZE,
s->s3->server_random,SSL3_RANDOM_SIZE,
s->s3->client_random,SSL3_RANDOM_SIZE,
@@ -358,7 +369,7 @@ int tls1_change_cipher_state(SSL *s, int which)
{
if (s->s3->tmp.new_cipher->algorithm2 & TLS1_STREAM_MAC)
s->mac_flags |= SSL_MAC_FLAG_READ_MAC_STREAM;
- else
+ else
s->mac_flags &= ~SSL_MAC_FLAG_READ_MAC_STREAM;
if (s->enc_read_ctx != NULL)
@@ -445,7 +456,11 @@ int tls1_change_cipher_state(SSL *s, int which)
j=is_export ? (cl < SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher) ?
cl : SSL_C_EXPORT_KEYLENGTH(s->s3->tmp.new_cipher)) : cl;
/* Was j=(exp)?5:EVP_CIPHER_key_length(c); */
- k=EVP_CIPHER_iv_length(c);
+ /* If GCM mode only part of IV comes from PRF */
+ if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
+ k = EVP_GCM_TLS_FIXED_IV_LEN;
+ else
+ k=EVP_CIPHER_iv_length(c);
if ( (which == SSL3_CHANGE_CIPHER_CLIENT_WRITE) ||
(which == SSL3_CHANGE_CIPHER_SERVER_READ))
{
@@ -474,10 +489,14 @@ int tls1_change_cipher_state(SSL *s, int which)
}
memcpy(mac_secret,ms,i);
- mac_key = EVP_PKEY_new_mac_key(mac_type, NULL,
- mac_secret,*mac_secret_size);
- EVP_DigestSignInit(mac_ctx,NULL,m,NULL,mac_key);
- EVP_PKEY_free(mac_key);
+
+ if (!(EVP_CIPHER_flags(c)&EVP_CIPH_FLAG_AEAD_CIPHER))
+ {
+ mac_key = EVP_PKEY_new_mac_key(mac_type, NULL,
+ mac_secret,*mac_secret_size);
+ EVP_DigestSignInit(mac_ctx,NULL,m,NULL,mac_key);
+ EVP_PKEY_free(mac_key);
+ }
#ifdef TLS_DEBUG
printf("which = %04X\nmac key=",which);
{ int z; for (z=0; z<i; z++) printf("%02X%c",ms[z],((z+1)%16)?' ':'\n'); }
@@ -487,7 +506,7 @@ printf("which = %04X\nmac key=",which);
/* In here I set both the read and write key/iv to the
* same value since only the correct one will be used :-).
*/
- if (!tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+ if (!tls1_PRF(ssl_get_algorithm2(s),
exp_label,exp_label_len,
s->s3->client_random,SSL3_RANDOM_SIZE,
s->s3->server_random,SSL3_RANDOM_SIZE,
@@ -498,7 +517,7 @@ printf("which = %04X\nmac key=",which);
if (k > 0)
{
- if (!tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+ if (!tls1_PRF(ssl_get_algorithm2(s),
TLS_MD_IV_BLOCK_CONST,TLS_MD_IV_BLOCK_CONST_SIZE,
s->s3->client_random,SSL3_RANDOM_SIZE,
s->s3->server_random,SSL3_RANDOM_SIZE,
@@ -524,7 +543,19 @@ printf("which = %04X\nmac key=",which);
}
#endif /* KSSL_DEBUG */
- EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
+ if (EVP_CIPHER_mode(c) == EVP_CIPH_GCM_MODE)
+ {
+ EVP_CipherInit_ex(dd,c,NULL,key,NULL,(which & SSL3_CC_WRITE));
+ EVP_CIPHER_CTX_ctrl(dd, EVP_CTRL_GCM_SET_IV_FIXED, k, iv);
+ }
+ else
+ EVP_CipherInit_ex(dd,c,NULL,key,iv,(which & SSL3_CC_WRITE));
+
+ /* Needed for "composite" AEADs, such as RC4-HMAC-MD5 */
+ if ((EVP_CIPHER_flags(c)&EVP_CIPH_FLAG_AEAD_CIPHER) && *mac_secret_size)
+ EVP_CIPHER_CTX_ctrl(dd,EVP_CTRL_AEAD_SET_MAC_KEY,
+ *mac_secret_size,mac_secret);
+
#ifdef TLS_DEBUG
printf("which = %04X\nkey=",which);
{ int z; for (z=0; z<EVP_CIPHER_key_length(c); z++) printf("%02X%c",key[z],((z+1)%16)?' ':'\n'); }
@@ -606,7 +637,8 @@ printf("\nkey block\n");
{ int z; for (z=0; z<num; z++) printf("%02X%c",p1[z],((z+1)%16)?' ':'\n'); }
#endif
- if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS))
+ if (!(s->options & SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS)
+ && s->method->version <= TLS1_VERSION)
{
/* enable vulnerability countermeasure for CBC ciphers with
* known-IV problem (http://www.openssl.org/~bodo/tls-cbc.txt)
@@ -640,14 +672,14 @@ int tls1_enc(SSL *s, int send)
SSL3_RECORD *rec;
EVP_CIPHER_CTX *ds;
unsigned long l;
- int bs,i,ii,j,k,n=0;
+ int bs,i,ii,j,k,pad=0;
const EVP_CIPHER *enc;
if (send)
{
if (EVP_MD_CTX_md(s->write_hash))
{
- n=EVP_MD_CTX_size(s->write_hash);
+ int n=EVP_MD_CTX_size(s->write_hash);
OPENSSL_assert(n >= 0);
}
ds=s->enc_write_ctx;
@@ -655,13 +687,34 @@ int tls1_enc(SSL *s, int send)
if (s->enc_write_ctx == NULL)
enc=NULL;
else
+ {
+ int ivlen;
enc=EVP_CIPHER_CTX_cipher(s->enc_write_ctx);
+ /* For TLSv1.1 and later explicit IV */
+ if (s->version >= TLS1_1_VERSION
+ && EVP_CIPHER_mode(enc) == EVP_CIPH_CBC_MODE)
+ ivlen = EVP_CIPHER_iv_length(enc);
+ else
+ ivlen = 0;
+ if (ivlen > 1)
+ {
+ if ( rec->data != rec->input)
+ /* we can't write into the input stream:
+ * Can this ever happen?? (steve)
+ */
+ fprintf(stderr,
+ "%s:%d: rec->data != rec->input\n",
+ __FILE__, __LINE__);
+ else if (RAND_bytes(rec->input, ivlen) <= 0)
+ return -1;
+ }
+ }
}
else
{
if (EVP_MD_CTX_md(s->read_hash))
{
- n=EVP_MD_CTX_size(s->read_hash);
+ int n=EVP_MD_CTX_size(s->read_hash);
OPENSSL_assert(n >= 0);
}
ds=s->enc_read_ctx;
@@ -687,7 +740,43 @@ int tls1_enc(SSL *s, int send)
l=rec->length;
bs=EVP_CIPHER_block_size(ds->cipher);
- if ((bs != 1) && send)
+ if (EVP_CIPHER_flags(ds->cipher)&EVP_CIPH_FLAG_AEAD_CIPHER)
+ {
+ unsigned char buf[13],*seq;
+
+ seq = send?s->s3->write_sequence:s->s3->read_sequence;
+
+ if (s->version == DTLS1_VERSION || s->version == DTLS1_BAD_VER)
+ {
+ unsigned char dtlsseq[9],*p=dtlsseq;
+
+ s2n(send?s->d1->w_epoch:s->d1->r_epoch,p);
+ memcpy(p,&seq[2],6);
+ memcpy(buf,dtlsseq,8);
+ }
+ else
+ {
+ memcpy(buf,seq,8);
+ for (i=7; i>=0; i--) /* increment */
+ {
+ ++seq[i];
+ if (seq[i] != 0) break;
+ }
+ }
+
+ buf[8]=rec->type;
+ buf[9]=(unsigned char)(s->version>>8);
+ buf[10]=(unsigned char)(s->version);
+ buf[11]=rec->length>>8;
+ buf[12]=rec->length&0xff;
+ pad=EVP_CIPHER_CTX_ctrl(ds,EVP_CTRL_AEAD_TLS1_AAD,13,buf);
+ if (send)
+ {
+ l+=pad;
+ rec->length+=pad;
+ }
+ }
+ else if ((bs != 1) && send)
{
i=bs-((int)l%bs);
@@ -728,13 +817,25 @@ int tls1_enc(SSL *s, int send)
{
if (l == 0 || l%bs != 0)
{
+ if (s->version >= TLS1_1_VERSION)
+ return -1;
SSLerr(SSL_F_TLS1_ENC,SSL_R_BLOCK_CIPHER_PAD_IS_WRONG);
ssl3_send_alert(s,SSL3_AL_FATAL,SSL_AD_DECRYPTION_FAILED);
return 0;
}
}
- EVP_Cipher(ds,rec->data,rec->input,l);
+ i = EVP_Cipher(ds,rec->data,rec->input,l);
+ if ((EVP_CIPHER_flags(ds->cipher)&EVP_CIPH_FLAG_CUSTOM_CIPHER)
+ ?(i<0)
+ :(i==0))
+ return -1; /* AEAD can fail to verify MAC */
+ if (EVP_CIPHER_mode(enc) == EVP_CIPH_GCM_MODE && !send)
+ {
+ rec->data += EVP_GCM_TLS_EXPLICIT_IV_LEN;
+ rec->input += EVP_GCM_TLS_EXPLICIT_IV_LEN;
+ rec->length -= EVP_GCM_TLS_EXPLICIT_IV_LEN;
+ }
#ifdef KSSL_DEBUG
{
@@ -784,8 +885,17 @@ int tls1_enc(SSL *s, int send)
return -1;
}
}
- rec->length-=i;
+ rec->length -=i;
+ if (s->version >= TLS1_1_VERSION
+ && EVP_CIPHER_CTX_mode(ds) == EVP_CIPH_CBC_MODE)
+ {
+ rec->data += bs; /* skip the explicit IV */
+ rec->input += bs;
+ rec->length -= bs;
+ }
}
+ if (pad && !send)
+ rec->length -= pad;
}
return(1);
}
@@ -841,7 +951,7 @@ int tls1_final_finish_mac(SSL *s,
for (idx=0;ssl_get_handshake_digest(idx,&mask,&md);idx++)
{
- if (mask & s->s3->tmp.new_cipher->algorithm2)
+ if (mask & ssl_get_algorithm2(s))
{
int hashsize = EVP_MD_size(md);
if (hashsize < 0 || hashsize > (int)(sizeof buf - (size_t)(q-buf)))
@@ -860,7 +970,7 @@ int tls1_final_finish_mac(SSL *s,
}
}
- if (!tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+ if (!tls1_PRF(ssl_get_algorithm2(s),
str,slen, buf,(int)(q-buf), NULL,0, NULL,0, NULL,0,
s->session->master_key,s->session->master_key_length,
out,buf2,sizeof buf2))
@@ -970,6 +1080,7 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
const void *co = NULL, *so = NULL;
int col = 0, sol = 0;
+
#ifdef KSSL_DEBUG
printf ("tls1_generate_master_secret(%p,%p, %p, %d)\n", s,out, p,len);
#endif /* KSSL_DEBUG */
@@ -986,7 +1097,7 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
}
#endif
- tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+ tls1_PRF(ssl_get_algorithm2(s),
TLS_MD_MASTER_SECRET_CONST,TLS_MD_MASTER_SECRET_CONST_SIZE,
s->s3->client_random,SSL3_RANDOM_SIZE,
co, col,
@@ -994,6 +1105,16 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
so, sol,
p,len,
s->session->master_key,buff,sizeof buff);
+#ifdef SSL_DEBUG
+ fprintf(stderr, "Premaster Secret:\n");
+ BIO_dump_fp(stderr, (char *)p, len);
+ fprintf(stderr, "Client Random:\n");
+ BIO_dump_fp(stderr, (char *)s->s3->client_random, SSL3_RANDOM_SIZE);
+ fprintf(stderr, "Server Random:\n");
+ BIO_dump_fp(stderr, (char *)s->s3->server_random, SSL3_RANDOM_SIZE);
+ fprintf(stderr, "Master Secret:\n");
+ BIO_dump_fp(stderr, (char *)s->session->master_key, SSL3_MASTER_SECRET_SIZE);
+#endif
#ifdef KSSL_DEBUG
printf ("tls1_generate_master_secret() complete\n");
@@ -1001,6 +1122,95 @@ int tls1_generate_master_secret(SSL *s, unsigned char *out, unsigned char *p,
return(SSL3_MASTER_SECRET_SIZE);
}
+int tls1_export_keying_material(SSL *s, unsigned char *out, size_t olen,
+ const char *label, size_t llen, const unsigned char *context,
+ size_t contextlen, int use_context)
+ {
+ unsigned char *buff;
+ unsigned char *val = NULL;
+ size_t vallen, currentvalpos;
+ int rv;
+
+#ifdef KSSL_DEBUG
+ printf ("tls1_export_keying_material(%p,%p,%d,%s,%d,%p,%d)\n", s, out, olen, label, llen, p, plen);
+#endif /* KSSL_DEBUG */
+
+ buff = OPENSSL_malloc(olen);
+ if (buff == NULL) goto err2;
+
+ /* construct PRF arguments
+ * we construct the PRF argument ourself rather than passing separate
+ * values into the TLS PRF to ensure that the concatenation of values
+ * does not create a prohibited label.
+ */
+ vallen = llen + SSL3_RANDOM_SIZE * 2;
+ if (use_context)
+ {
+ vallen += 2 + contextlen;
+ }
+
+ val = OPENSSL_malloc(vallen);
+ if (val == NULL) goto err2;
+ currentvalpos = 0;
+ memcpy(val + currentvalpos, (unsigned char *) label, llen);
+ currentvalpos += llen;
+ memcpy(val + currentvalpos, s->s3->client_random, SSL3_RANDOM_SIZE);
+ currentvalpos += SSL3_RANDOM_SIZE;
+ memcpy(val + currentvalpos, s->s3->server_random, SSL3_RANDOM_SIZE);
+ currentvalpos += SSL3_RANDOM_SIZE;
+
+ if (use_context)
+ {
+ val[currentvalpos] = (contextlen >> 8) & 0xff;
+ currentvalpos++;
+ val[currentvalpos] = contextlen & 0xff;
+ currentvalpos++;
+ if ((contextlen > 0) || (context != NULL))
+ {
+ memcpy(val + currentvalpos, context, contextlen);
+ }
+ }
+
+ /* disallow prohibited labels
+ * note that SSL3_RANDOM_SIZE > max(prohibited label len) =
+ * 15, so size of val > max(prohibited label len) = 15 and the
+ * comparisons won't have buffer overflow
+ */
+ if (memcmp(val, TLS_MD_CLIENT_FINISH_CONST,
+ TLS_MD_CLIENT_FINISH_CONST_SIZE) == 0) goto err1;
+ if (memcmp(val, TLS_MD_SERVER_FINISH_CONST,
+ TLS_MD_SERVER_FINISH_CONST_SIZE) == 0) goto err1;
+ if (memcmp(val, TLS_MD_MASTER_SECRET_CONST,
+ TLS_MD_MASTER_SECRET_CONST_SIZE) == 0) goto err1;
+ if (memcmp(val, TLS_MD_KEY_EXPANSION_CONST,
+ TLS_MD_KEY_EXPANSION_CONST_SIZE) == 0) goto err1;
+
+ rv = tls1_PRF(s->s3->tmp.new_cipher->algorithm2,
+ val, vallen,
+ NULL, 0,
+ NULL, 0,
+ NULL, 0,
+ NULL, 0,
+ s->session->master_key,s->session->master_key_length,
+ out,buff,olen);
+
+#ifdef KSSL_DEBUG
+ printf ("tls1_export_keying_material() complete\n");
+#endif /* KSSL_DEBUG */
+ goto ret;
+err1:
+ SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, SSL_R_TLS_ILLEGAL_EXPORTER_LABEL);
+ rv = 0;
+ goto ret;
+err2:
+ SSLerr(SSL_F_TLS1_EXPORT_KEYING_MATERIAL, ERR_R_MALLOC_FAILURE);
+ rv = 0;
+ret:
+ if (buff != NULL) OPENSSL_free(buff);
+ if (val != NULL) OPENSSL_free(val);
+ return(rv);
+ }
+
int tls1_alert_code(int code)
{
switch (code)
@@ -1042,4 +1252,3 @@ int tls1_alert_code(int code)
default: return(-1);
}
}
-
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 08:08:53 +0000