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Don't crash when processing a zero-length, TLS >= 1.1 record.

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The previous CBC patch was bugged in that there was a path through enc()
in s3_pkt.c/d1_pkt.c which didn't set orig_len. orig_len would be left
at the previous value which could suggest that the packet was a
sufficient length when it wasn't.
(cherry picked from commit 6cb19b7681)
This commit is contained in:
Ben Laurie 2013-01-28 17:33:18 +00:00 committed by Dr. Stephen Henson
parent 2acc020b77
commit 93cab6b319
5 changed files with 24 additions and 7 deletions
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1
ssl/d1_enc.c
View file

@ -245,7 +245,6 @@ int dtls1_enc(SSL *s, int send)
}
#endif /* KSSL_DEBUG */
rec->orig_len = rec->length;
if ((bs != 1) && !send)
return tls1_cbc_remove_padding(s, rec, bs, mac_size);
}

1
ssl/d1_pkt.c
View file

@ -414,6 +414,7 @@ dtls1_process_record(SSL *s)
/* decrypt in place in 'rr->input' */
rr->data=rr->input;
rr->orig_len=rr->length;
enc_err = s->method->ssl3_enc->enc(s,0);
if (enc_err <= 0)

11
ssl/s3_enc.c
View file

@ -487,6 +487,15 @@ void ssl3_cleanup_key_block(SSL *s)
s->s3->tmp.key_block_length=0;
}
/* ssl3_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
*
* Returns:
* 0: (in non-constant time) if the record is publically invalid (i.e. too
* short etc).
* 1: if the record's padding is valid / the encryption was successful.
* -1: if the record's padding is invalid or, if sending, an internal error
* occured.
*/
int ssl3_enc(SSL *s, int send)
{
SSL3_RECORD *rec;
@ -553,8 +562,6 @@ int ssl3_enc(SSL *s, int send)
EVP_Cipher(ds,rec->data,rec->input,l);
rec->orig_len = rec->length;
if (EVP_MD_CTX_md(s->read_hash) != NULL)
mac_size = EVP_MD_CTX_size(s->read_hash);
if ((bs != 1) && !send)

5
ssl/s3_pkt.c
View file

@ -401,8 +401,13 @@ fprintf(stderr, "Record type=%d, Length=%d\n", rr->type, rr->length);
/* decrypt in place in 'rr->input' */
rr->data=rr->input;
rr->orig_len=rr->length;
enc_err = s->method->ssl3_enc->enc(s,0);
/* enc_err is:
* 0: (in non-constant time) if the record is publically invalid.
* 1: if the padding is valid
* -1: if the padding is invalid */
if (enc_err == 0)
{
/* SSLerr() and ssl3_send_alert() have been called */

13
ssl/t1_enc.c
View file

@ -691,6 +691,15 @@ err:
return(ret);
}
/* tls1_enc encrypts/decrypts the record in |s->wrec| / |s->rrec|, respectively.
*
* Returns:
* 0: (in non-constant time) if the record is publically invalid (i.e. too
* short etc).
* 1: if the record's padding is valid / the encryption was successful.
* -1: if the record's padding/AEAD-authenticator is invalid or, if sending,
* an internal error occured.
*/
int tls1_enc(SSL *s, int send)
{
SSL3_RECORD *rec;
@ -841,8 +850,6 @@ 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;
@ -870,8 +877,6 @@ int tls1_enc(SSL *s, int send)
}
#endif /* KSSL_DEBUG */
rec->orig_len = rec->length;
ret = 1;
if (EVP_MD_CTX_md(s->read_hash) != NULL)
mac_size = EVP_MD_CTX_size(s->read_hash);