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- djm@cvs.openbsd.org 2004/10/29 23:56:17 

[bufaux.c bufaux.h buffer.c buffer.h]
     introduce a new buffer API that returns an error rather than fatal()ing
     when presented with bad data; ok markus@
This commit is contained in:
Darren Tucker 2004-11-05 20:41:24 +11:00
parent ce327b62ac
commit 50dbe8314b
5 changed files with 234 additions and 61 deletions
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6
ChangeLog
View File

@ -54,6 +54,10 @@
- djm@cvs.openbsd.org 2004/10/29 22:53:56
[clientloop.c misc.h readpass.c ssh-agent.c]
factor out common permission-asking code to separate function; ok markus@
- djm@cvs.openbsd.org 2004/10/29 23:56:17
[bufaux.c bufaux.h buffer.c buffer.h]
introduce a new buffer API that returns an error rather than fatal()ing
when presented with bad data; ok markus@
20041102
- (dtucker) [configure.ac includes.h] Bug #947: Fix compile error on HP-UX
@ -1833,4 +1837,4 @@
- (djm) Trim deprecated options from INSTALL. Mention UsePAM
- (djm) Fix quote handling in sftp; Patch from admorten AT umich.edu
$Id: ChangeLog,v 1.3576 2004/11/05 09:38:03 dtucker Exp $
$Id: ChangeLog,v 1.3577 2004/11/05 09:41:24 dtucker Exp $

221
bufaux.c
View File

@ -37,7 +37,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: bufaux.c,v 1.32 2004/02/23 15:12:46 markus Exp $");
RCSID("$OpenBSD: bufaux.c,v 1.33 2004/10/29 23:56:17 djm Exp $");
#include <openssl/bn.h>
#include "bufaux.h"
@ -49,8 +49,8 @@ RCSID("$OpenBSD: bufaux.c,v 1.32 2004/02/23 15:12:46 markus Exp $");
* Stores an BIGNUM in the buffer with a 2-byte msb first bit count, followed
* by (bits+7)/8 bytes of binary data, msb first.
*/
void
buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
int
buffer_put_bignum_ret(Buffer *buffer, const BIGNUM *value)
{
int bits = BN_num_bits(value);
int bin_size = (bits + 7) / 8;
@ -60,9 +60,11 @@ buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
/* Get the value of in binary */
oi = BN_bn2bin(value, buf);
if (oi != bin_size)
fatal("buffer_put_bignum: BN_bn2bin() failed: oi %d != bin_size %d",
if (oi != bin_size) {
error("buffer_put_bignum_ret: BN_bn2bin() failed: oi %d != bin_size %d",
oi, bin_size);
return (-1);
}
/* Store the number of bits in the buffer in two bytes, msb first. */
PUT_16BIT(msg, bits);
@ -72,36 +74,63 @@ buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
memset(buf, 0, bin_size);
xfree(buf);
return (0);
}
void
buffer_put_bignum(Buffer *buffer, const BIGNUM *value)
{
if (buffer_put_bignum_ret(buffer, value) == -1)
fatal("buffer_put_bignum: buffer error");
}
/*
* Retrieves an BIGNUM from the buffer.
*/
void
buffer_get_bignum(Buffer *buffer, BIGNUM *value)
int
buffer_get_bignum_ret(Buffer *buffer, BIGNUM *value)
{
u_int bits, bytes;
u_char buf[2], *bin;
/* Get the number for bits. */
buffer_get(buffer, (char *) buf, 2);
if (buffer_get_ret(buffer, (char *) buf, 2) == -1) {
error("buffer_get_bignum_ret: invalid length");
return (-1);
}
bits = GET_16BIT(buf);
/* Compute the number of binary bytes that follow. */
bytes = (bits + 7) / 8;
if (bytes > 8 * 1024)
fatal("buffer_get_bignum: cannot handle BN of size %d", bytes);
if (buffer_len(buffer) < bytes)
fatal("buffer_get_bignum: input buffer too small");
if (bytes > 8 * 1024) {
error("buffer_get_bignum_ret: cannot handle BN of size %d", bytes);
return (-1);
}
if (buffer_len(buffer) < bytes) {
error("buffer_get_bignum_ret: input buffer too small");
return (-1);
}
bin = buffer_ptr(buffer);
BN_bin2bn(bin, bytes, value);
buffer_consume(buffer, bytes);
if (buffer_consume_ret(buffer, bytes) == -1) {
error("buffer_get_bignum_ret: buffer_consume failed");
return (-1);
}
return (0);
}
void
buffer_get_bignum(Buffer *buffer, BIGNUM *value)
{
if (buffer_get_bignum_ret(buffer, value) == -1)
fatal("buffer_get_bignum: buffer error");
}
/*
* Stores an BIGNUM in the buffer in SSH2 format.
*/
void
buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
int
buffer_put_bignum2_ret(Buffer *buffer, const BIGNUM *value)
{
u_int bytes;
u_char *buf;
@ -110,69 +139,140 @@ buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
if (BN_is_zero(value)) {
buffer_put_int(buffer, 0);
return;
return 0;
}
if (value->neg) {
error("buffer_put_bignum2_ret: negative numbers not supported");
return (-1);
}
if (value->neg)
fatal("buffer_put_bignum2: negative numbers not supported");
bytes = BN_num_bytes(value) + 1; /* extra padding byte */
if (bytes < 2)
fatal("buffer_put_bignum2: BN too small");
if (bytes < 2) {
error("buffer_put_bignum2_ret: BN too small");
return (-1);
}
buf = xmalloc(bytes);
buf[0] = '\0';
/* Get the value of in binary */
oi = BN_bn2bin(value, buf+1);
if (oi != bytes-1)
fatal("buffer_put_bignum2: BN_bn2bin() failed: "
if (oi != bytes-1) {
error("buffer_put_bignum2_ret: BN_bn2bin() failed: "
"oi %d != bin_size %d", oi, bytes);
xfree(buf);
return (-1);
}
hasnohigh = (buf[1] & 0x80) ? 0 : 1;
buffer_put_string(buffer, buf+hasnohigh, bytes-hasnohigh);
memset(buf, 0, bytes);
xfree(buf);
return (0);
}
void
buffer_put_bignum2(Buffer *buffer, const BIGNUM *value)
{
if (buffer_put_bignum2_ret(buffer, value) == -1)
fatal("buffer_put_bignum2: buffer error");
}
int
buffer_get_bignum2_ret(Buffer *buffer, BIGNUM *value)
{
u_int len;
u_char *bin;
if ((bin = buffer_get_string_ret(buffer, &len)) == NULL) {
error("buffer_get_bignum2_ret: invalid bignum");
return (-1);
}
if (len > 0 && (bin[0] & 0x80)) {
error("buffer_get_bignum2_ret: negative numbers not supported");
return (-1);
}
if (len > 8 * 1024) {
error("buffer_get_bignum2_ret: cannot handle BN of size %d", len);
return (-1);
}
BN_bin2bn(bin, len, value);
xfree(bin);
return (0);
}
void
buffer_get_bignum2(Buffer *buffer, BIGNUM *value)
{
u_int len;
u_char *bin = buffer_get_string(buffer, &len);
if (len > 0 && (bin[0] & 0x80))
fatal("buffer_get_bignum2: negative numbers not supported");
if (len > 8 * 1024)
fatal("buffer_get_bignum2: cannot handle BN of size %d", len);
BN_bin2bn(bin, len, value);
xfree(bin);
if (buffer_get_bignum2_ret(buffer, value) == -1)
fatal("buffer_get_bignum2: buffer error");
}
/*
* Returns integers from the buffer (msb first).
*/
u_short
buffer_get_short(Buffer *buffer)
int
buffer_get_short_ret(u_short *ret, Buffer *buffer)
{
u_char buf[2];
buffer_get(buffer, (char *) buf, 2);
return GET_16BIT(buf);
if (buffer_get_ret(buffer, (char *) buf, 2) == -1)
return (-1);
*ret = GET_16BIT(buf);
return (0);
}
u_short
buffer_get_short(Buffer *buffer)
{
u_short ret;
if (buffer_get_short_ret(&ret, buffer) == -1)
fatal("buffer_get_short: buffer error");
return (ret);
}
int
buffer_get_int_ret(u_int *ret, Buffer *buffer)
{
u_char buf[4];
if (buffer_get_ret(buffer, (char *) buf, 4) == -1)
return (-1);
*ret = GET_32BIT(buf);
return (0);
}
u_int
buffer_get_int(Buffer *buffer)
{
u_char buf[4];
u_int ret;
buffer_get(buffer, (char *) buf, 4);
return GET_32BIT(buf);
if (buffer_get_int_ret(&ret, buffer) == -1)
fatal("buffer_get_int: buffer error");
return (ret);
}
int
buffer_get_int64_ret(u_int64_t *ret, Buffer *buffer)
{
u_char buf[8];
if (buffer_get_ret(buffer, (char *) buf, 8) == -1)
return (-1);
*ret = GET_64BIT(buf);
return (0);
}
u_int64_t
buffer_get_int64(Buffer *buffer)
{
u_char buf[8];
u_int64_t ret;
buffer_get(buffer, (char *) buf, 8);
return GET_64BIT(buf);
if (buffer_get_int64_ret(&ret, buffer) == -1)
fatal("buffer_get_int: buffer error");
return (ret);
}
/*
@ -214,25 +314,41 @@ buffer_put_int64(Buffer *buffer, u_int64_t value)
* to the returned string, and is not counted in length.
*/
void *
buffer_get_string(Buffer *buffer, u_int *length_ptr)
buffer_get_string_ret(Buffer *buffer, u_int *length_ptr)
{
u_char *value;
u_int len;
/* Get the length. */
len = buffer_get_int(buffer);
if (len > 256 * 1024)
fatal("buffer_get_string: bad string length %u", len);
if (len > 256 * 1024) {
error("buffer_get_string_ret: bad string length %u", len);
return (NULL);
}
/* Allocate space for the string. Add one byte for a null character. */
value = xmalloc(len + 1);
/* Get the string. */
buffer_get(buffer, value, len);
if (buffer_get_ret(buffer, value, len) == -1) {
error("buffer_get_string_ret: buffer_get failed");
xfree(value);
return (NULL);
}
/* Append a null character to make processing easier. */
value[len] = 0;
/* Optionally return the length of the string. */
if (length_ptr)
*length_ptr = len;
return value;
return (value);
}
void *
buffer_get_string(Buffer *buffer, u_int *length_ptr)
{
void *ret;
if ((ret = buffer_get_string_ret(buffer, length_ptr)) == NULL)
fatal("buffer_get_string: buffer error");
return (ret);
}
/*
@ -255,12 +371,23 @@ buffer_put_cstring(Buffer *buffer, const char *s)
/*
* Returns a character from the buffer (0 - 255).
*/
int
buffer_get_char_ret(char *ret, Buffer *buffer)
{
if (buffer_get_ret(buffer, ret, 1) == -1) {
error("buffer_get_char_ret: buffer_get_ret failed");
return (-1);
}
return (0);
}
int
buffer_get_char(Buffer *buffer)
{
char ch;
buffer_get(buffer, &ch, 1);
if (buffer_get_char_ret(&ch, buffer) == -1)
fatal("buffer_get_char: buffer error");
return (u_char) ch;
}

12
bufaux.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: bufaux.h,v 1.19 2003/11/10 16:23:41 jakob Exp $ */
/* $OpenBSD: bufaux.h,v 1.20 2004/10/29 23:56:17 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -42,4 +42,14 @@ void buffer_put_cstring(Buffer *, const char *);
#define buffer_skip_string(b) \
do { u_int l = buffer_get_int(b); buffer_consume(b, l); } while(0)
int buffer_put_bignum_ret(Buffer *, const BIGNUM *);
int buffer_get_bignum_ret(Buffer *, BIGNUM *);
int buffer_put_bignum2_ret(Buffer *, const BIGNUM *);
int buffer_get_bignum2_ret(Buffer *, BIGNUM *);
int buffer_get_short_ret(u_short *, Buffer *);
int buffer_get_int_ret(u_int *, Buffer *);
int buffer_get_int64_ret(u_int64_t *, Buffer *);
void *buffer_get_string_ret(Buffer *, u_int *);
int buffer_get_char_ret(char *, Buffer *);
#endif /* BUFAUX_H */

50
buffer.c
View File

@ -12,7 +12,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: buffer.c,v 1.21 2003/11/21 11:57:03 djm Exp $");
RCSID("$OpenBSD: buffer.c,v 1.22 2004/10/29 23:56:17 djm Exp $");
#include "xmalloc.h"
#include "buffer.h"
@ -126,34 +126,62 @@ buffer_len(Buffer *buffer)
/* Gets data from the beginning of the buffer. */
int
buffer_get_ret(Buffer *buffer, void *buf, u_int len)
{
if (len > buffer->end - buffer->offset) {
error("buffer_get_ret: trying to get more bytes %d than in buffer %d",
len, buffer->end - buffer->offset);
return (-1);
}
memcpy(buf, buffer->buf + buffer->offset, len);
buffer->offset += len;
return (0);
}
void
buffer_get(Buffer *buffer, void *buf, u_int len)
{
if (len > buffer->end - buffer->offset)
fatal("buffer_get: trying to get more bytes %d than in buffer %d",
len, buffer->end - buffer->offset);
memcpy(buf, buffer->buf + buffer->offset, len);
buffer->offset += len;
if (buffer_get_ret(buffer, buf, len) == -1)
fatal("buffer_get: buffer error");
}
/* Consumes the given number of bytes from the beginning of the buffer. */
int
buffer_consume_ret(Buffer *buffer, u_int bytes)
{
if (bytes > buffer->end - buffer->offset) {
error("buffer_consume_ret: trying to get more bytes than in buffer");
return (-1);
}
buffer->offset += bytes;
return (0);
}
void
buffer_consume(Buffer *buffer, u_int bytes)
{
if (bytes > buffer->end - buffer->offset)
fatal("buffer_consume: trying to get more bytes than in buffer");
buffer->offset += bytes;
if (buffer_consume_ret(buffer, bytes) == -1)
fatal("buffer_consume: buffer error");
}
/* Consumes the given number of bytes from the end of the buffer. */
int
buffer_consume_end_ret(Buffer *buffer, u_int bytes)
{
if (bytes > buffer->end - buffer->offset)
return (-1);
buffer->end -= bytes;
return (0);
}
void
buffer_consume_end(Buffer *buffer, u_int bytes)
{
if (bytes > buffer->end - buffer->offset)
if (buffer_consume_end_ret(buffer, bytes) == -1)
fatal("buffer_consume_end: trying to get more bytes than in buffer");
buffer->end -= bytes;
}
/* Returns a pointer to the first used byte in the buffer. */

6
buffer.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: buffer.h,v 1.11 2002/03/04 17:27:39 stevesk Exp $ */
/* $OpenBSD: buffer.h,v 1.12 2004/10/29 23:56:17 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
@ -40,4 +40,8 @@ void buffer_consume_end(Buffer *, u_int);
void buffer_dump(Buffer *);
int buffer_get_ret(Buffer *, void *, u_int);
int buffer_consume_ret(Buffer *, u_int);
int buffer_consume_end_ret(Buffer *, u_int);
#endif /* BUFFER_H */