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- Don't allow setting memLevel since that doesn't work properly

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- Better handling of the case where compressing makes the data
larger (possibly only happens when memLevel is adjusted, but better
to be safe)

--HG--
extra : convert_revision : b31879a384d3bf8cbcbe2ed731d7d79d49799b1d
This commit is contained in:
Matt Johnston 2011-02-28 13:51:27 +00:00
parent 84c51f933c
commit d634b502cf
3 changed files with 23 additions and 15 deletions
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14
options.h
View File

@ -133,19 +133,15 @@ much traffic. */
/* #define DSS_PROTOK */
/* Control the memory/performance/compression tradeoff for zlib.
* Set windowBits=8, memLevel=1 for least memory usage, see your system's
* Set windowBits=8 for least memory usage, see your system's
* zlib.h for full details.
* Default settings (windowBits=15, memLevel=8) will use
* 256kB for compression + 32kB for decompression.
* windowBits=8, memLevel=1 will use 10kB compression + 32kB decompression.
* Note that windowBits is only set for deflate() - inflate() always uses the
* default of 15 so as to interoperate with other clients. */
* Default settings (windowBits=15) will use 256kB for compression
* windowBits=8 will use 129kB for compression.
* Both modes will use ~35kB for decompression (using windowBits=15 for
* interoperability) */
#ifndef DROPBEAR_ZLIB_WINDOW_BITS
#define DROPBEAR_ZLIB_WINDOW_BITS 15
#endif
#ifndef DROPBEAR_ZLIB_MEM_LEVEL
#define DROPBEAR_ZLIB_MEM_LEVEL 8
#endif
/* Whether to do reverse DNS lookups. */
#define DO_HOST_LOOKUP

20
packet.c
View File

@ -41,7 +41,7 @@ static void make_mac(unsigned int seqno, const struct key_context_directional *
unsigned char *output_mac);
static int checkmac();
#define ZLIB_COMPRESS_INCR 20 /* this is 12 bytes + 0.1% of 8000 bytes */
#define ZLIB_COMPRESS_INCR 100
#define ZLIB_DECOMPRESS_INCR 100
#ifndef DISABLE_ZLIB
static buffer* buf_decompress(buffer* buf, unsigned int len);
@ -452,14 +452,15 @@ void encrypt_packet() {
blocksize = ses.keys->trans.algo_crypt->blocksize;
mac_size = ses.keys->trans.algo_mac->hashsize;
/* Encrypted packet len is payload+5, then worst case is if we are 3 away
* from a blocksize multiple. In which case we need to pad to the
* multiple, then add another blocksize (or MIN_PACKET_LEN) */
encrypt_buf_size = (ses.writepayload->len+4+1) + MIN_PACKET_LEN + 3
/* Encrypted packet len is payload+5. We need to then make sure
* there is enough space for padding or MIN_PACKET_LEN.
* Add extra 3 since we need at least 4 bytes of padding */
encrypt_buf_size = (ses.writepayload->len+4+1)
+ MAX(MIN_PACKET_LEN, blocksize) + 3
/* add space for the MAC at the end */
+ mac_size
#ifndef DISABLE_ZLIB
/* zlib compression could lengthen the payload in some cases */
/* some extra in case 'compression' makes it larger */
+ ZLIB_COMPRESS_INCR
#endif
/* and an extra cleartext (stripped before transmission) byte for the
@ -473,7 +474,14 @@ void encrypt_packet() {
#ifndef DISABLE_ZLIB
/* compression */
if (is_compress_trans()) {
int compress_delta;
buf_compress(writebuf, ses.writepayload, ses.writepayload->len);
compress_delta = (writebuf->len - PACKET_PAYLOAD_OFF) - ses.writepayload->len;
/* Handle the case where 'compress' increased the size. */
if (compress_delta > ZLIB_COMPRESS_INCR) {
buf_resize(writebuf, writebuf->size + compress_delta);
}
} else
#endif
{

4
sysoptions.h
View File

@ -173,6 +173,10 @@
#define DROPBEAR_KEY_LINES /* ie we're using authorized_keys or known_hosts */
#endif
/* Changing this is inadvisable, it appears to have problems
* with flushing compressed data */
#define DROPBEAR_ZLIB_MEM_LEVEL 8
#if defined(ENABLE_SVR_PASSWORD_AUTH) && defined(ENABLE_SVR_PAM_AUTH)
#error "You can't turn on PASSWORD and PAM auth both at once. Fix it in options.h"
#endif