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[tcp] Fix potential use-after-free when accessing timestamp option 

Reported-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2010-07-07 12:57:08 +01:00
parent 3cefc5a3e0
commit 68c2f07f15
1 changed files with 7 additions and 4 deletions
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11
src/net/tcp.c
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@ -900,6 +900,7 @@ static int tcp_rx ( struct io_buffer *iobuf,
uint32_t seq;
uint32_t ack;
uint32_t win;
uint32_t ts_recent;
unsigned int flags;
size_t len;
int rc;
@ -941,6 +942,8 @@ static int tcp_rx ( struct io_buffer *iobuf,
flags = tcphdr->flags;
tcp_rx_opts ( tcp, ( ( ( void * ) tcphdr ) + sizeof ( *tcphdr ) ),
( hlen - sizeof ( *tcphdr ) ), &options );
ts_recent = ( options.tsopt ?
ntohl ( options.tsopt->tsval ) : tcp->ts_recent );
iob_pull ( iobuf, hlen );
len = iob_len ( iobuf );
@ -981,7 +984,7 @@ static int tcp_rx ( struct io_buffer *iobuf,
}
/* Handle new data, if any */
tcp_rx_data ( tcp, seq, iobuf );
tcp_rx_data ( tcp, seq, iob_disown ( iobuf ) );
seq += len;
/* Handle FIN, if present */
@ -990,9 +993,9 @@ static int tcp_rx ( struct io_buffer *iobuf,
seq++;
}
/* Update timestamp, if present and applicable */
if ( ( seq == tcp->rcv_ack ) && options.tsopt )
tcp->ts_recent = ntohl ( options.tsopt->tsval );
/* Update timestamp, if applicable */
if ( seq == tcp->rcv_ack )
tcp->ts_recent = ts_recent;
/* Dump out any state change as a result of the received packet */
tcp_dump_state ( tcp );