Commit af58be76 authored by Matt Caswell's avatar Matt Caswell
Browse files

Don't allow too many consecutive warning alerts 



Certain warning alerts are ignored if they are received. This can mean that
no progress will be made if one peer continually sends those warning alerts.
Implement a count so that we abort the connection if we receive too many.

Issue reported by Shi Lei.

Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
parent 7dc0ad4d

include/openssl/ssl.h

+1 −0
Original line number Diff line number Diff line
@@ -2485,6 +2485,7 @@ int ERR_load_SSL_strings(void); 
# define SSL_R_TLS_HEARTBEAT_PENDING                      366

# define SSL_R_TLS_ILLEGAL_EXPORTER_LABEL                 367

# define SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST             157

# define SSL_R_TOO_MANY_WARN_ALERTS                       409

# define SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS             314

# define SSL_R_UNABLE_TO_FIND_PUBLIC_KEY_PARAMETERS       239

# define SSL_R_UNABLE_TO_LOAD_SSL3_MD5_ROUTINES           242

ssl/record/rec_layer_d1.c

+16 −0
Original line number Diff line number Diff line
@@ -443,6 +443,14 @@ int dtls1_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf, 
        }

    }



    /*

     * Reset the count of consecutive warning alerts if we've got a non-empty

     * record that isn't an alert.

     */

    if (SSL3_RECORD_get_type(rr) != SSL3_RT_ALERT

            && SSL3_RECORD_get_length(rr) != 0)

        s->rlayer.alert_count = 0;



    /* we now have a packet which can be read and processed */



    if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
@@ -722,6 +730,14 @@ int dtls1_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf, 


        if (alert_level == SSL3_AL_WARNING) {

            s->s3->warn_alert = alert_descr;



            s->rlayer.alert_count++;

            if (s->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {

                al = SSL_AD_UNEXPECTED_MESSAGE;

                SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_R_TOO_MANY_WARN_ALERTS);

                goto f_err;

            }



            if (alert_descr == SSL_AD_CLOSE_NOTIFY) {

#ifndef OPENSSL_NO_SCTP

                /*

ssl/record/rec_layer_s3.c

+16 −0
Original line number Diff line number Diff line
@@ -1063,6 +1063,14 @@ int ssl3_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf, 
    } while (num_recs == 0);

    rr = &rr[curr_rec];



    /*

     * Reset the count of consecutive warning alerts if we've got a non-empty

     * record that isn't an alert.

     */

    if (SSL3_RECORD_get_type(rr) != SSL3_RT_ALERT

            && SSL3_RECORD_get_length(rr) != 0)

        s->rlayer.alert_count = 0;



    /* we now have a packet which can be read and processed */



    if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
@@ -1333,6 +1341,14 @@ int ssl3_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf, 
        if (alert_level == SSL3_AL_WARNING) {

            s->s3->warn_alert = alert_descr;

            SSL3_RECORD_set_read(rr);



            s->rlayer.alert_count++;

            if (s->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {

                al = SSL_AD_UNEXPECTED_MESSAGE;

                SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_TOO_MANY_WARN_ALERTS);

                goto f_err;

            }



            if (alert_descr == SSL_AD_CLOSE_NOTIFY) {

                s->shutdown |= SSL_RECEIVED_SHUTDOWN;

                return (0);

ssl/record/record.h

+2 −0
Original line number Diff line number Diff line
@@ -178,6 +178,8 @@ typedef struct record_layer_st { 
    unsigned char write_sequence[SEQ_NUM_SIZE];

    /* Set to true if this is the first record in a connection */

    unsigned int is_first_record;

    /* Count of the number of consecutive warning alerts received */

    unsigned int alert_count;

    DTLS_RECORD_LAYER *d;

} RECORD_LAYER;

ssl/record/record_locl.h

+2 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
 *                                                                           *

 *****************************************************************************/



#define MAX_WARN_ALERT_COUNT    5



/* Functions/macros provided by the RECORD_LAYER component */



#define RECORD_LAYER_get_rbuf(rl)               (&(rl)->rbuf)