Buffer: add ssh_buffer_(un)pack()
That function permits chaining of buffer values to minimize buffer handling in packet sending code. Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Этот коммит содержится в:
Aris Adamantiadis
Andreas Schneider
родитель
13c42bff3f
Коммит
835e34d1eb
@ -21,6 +21,8 @@
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#ifndef BUFFER_H_
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#define BUFFER_H_
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#include <stdarg.h>
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#include "libssh/libssh.h"
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/*
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* Describes a buffer state
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@ -46,6 +48,10 @@ int buffer_add_u16(ssh_buffer buffer, uint16_t data);
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int buffer_add_u32(ssh_buffer buffer, uint32_t data);
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int buffer_add_u64(ssh_buffer buffer, uint64_t data);
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int ssh_buffer_add_data(ssh_buffer buffer, const void *data, uint32_t len);
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int ssh_buffer_pack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap);
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int ssh_buffer_pack(struct ssh_buffer_struct *buffer, const char *format, ...);
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int ssh_buffer_unpack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap);
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int ssh_buffer_unpack(struct ssh_buffer_struct *buffer, const char *format, ...);
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int buffer_prepend_data(ssh_buffer buffer, const void *data, uint32_t len);
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int buffer_add_buffer(ssh_buffer buffer, ssh_buffer source);
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int ssh_buffer_reinit(ssh_buffer buffer);
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295
src/buffer.c
295
src/buffer.c
@ -24,6 +24,7 @@
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#ifndef _WIN32
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#include <netinet/in.h>
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@ -32,6 +33,8 @@
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#include "libssh/priv.h"
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#include "libssh/buffer.h"
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#include "libssh/misc.h"
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#include "libssh/dh.h"
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/**
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* @defgroup libssh_buffer The SSH buffer functions.
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@ -645,6 +648,298 @@ struct ssh_string_struct *buffer_get_mpint(struct ssh_buffer_struct *buffer) {
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return str;
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}
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/** @internal
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* @brief Add multiple values in a buffer on a single function call
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* @param[in] buffer The buffer to add to
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* @param[in] format A format string of arguments.
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* @param[in] ap A va_list of arguments.
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* @returns SSH_OK on success
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* SSH_ERROR on error
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* @see ssh_buffer_add_format() for format list values.
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*/
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int ssh_buffer_pack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap){
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int rc;
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const char *p;
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union {
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uint8_t byte;
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uint16_t word;
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uint32_t dword;
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uint64_t qword;
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ssh_string string;
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void *data;
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} o;
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char *cstring;
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bignum b;
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size_t len;
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for (p = format; *p != '\0'; p++) {
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switch(*p) {
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case 'b':
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o.byte = (uint8_t)va_arg(ap, unsigned int);
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rc = buffer_add_u8(buffer, o.byte);
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break;
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case 'w':
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o.word = (uint16_t)va_arg(ap, unsigned int);
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o.word = htons(o.word);
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rc = buffer_add_u16(buffer, o.word);
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break;
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case 'd':
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o.dword = va_arg(ap, uint32_t);
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o.dword = htonl(o.dword);
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rc = buffer_add_u32(buffer, o.dword);
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break;
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case 'q':
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o.qword = va_arg(ap, uint64_t);
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o.qword = htonll(o.qword);
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rc = buffer_add_u64(buffer, o.qword);
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break;
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case 'S':
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o.string = va_arg(ap, ssh_string);
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rc = buffer_add_ssh_string(buffer, o.string);
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o.string = NULL;
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break;
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case 's':
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cstring = va_arg(ap, char *);
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len = strlen(cstring);
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rc = buffer_add_u32(buffer, htonl(len));
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if (rc == SSH_OK){
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rc = ssh_buffer_add_data(buffer, cstring, len);
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}
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cstring = NULL;
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break;
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case 'P':
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len = va_arg(ap, size_t);
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o.data = va_arg(ap, void *);
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rc = ssh_buffer_add_data(buffer, o.data, len);
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o.data = NULL;
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break;
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case 'B':
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b = va_arg(ap, bignum);
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o.string = make_bignum_string(b);
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if(o.string == NULL){
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rc = SSH_ERROR;
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break;
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}
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rc = buffer_add_ssh_string(buffer, o.string);
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SAFE_FREE(o.string);
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break;
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default:
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SSH_LOG(SSH_LOG_WARN, "Invalid buffer format %c", *p);
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rc = SSH_ERROR;
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}
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if (rc != SSH_OK){
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break;
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}
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}
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return rc;
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}
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/** @internal
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* @brief Add multiple values in a buffer on a single function call
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* @param[in] buffer The buffer to add to
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* @param[in] format A format string of arguments. This string contains single
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* letters describing the order and type of arguments:
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* 'b': uint8_t (pushed in network byte order)
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* 'w': uint16_t (pushed in network byte order)
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* 'd': uint32_t (pushed in network byte order)
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* 'q': uint64_t (pushed in network byte order)
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* 'S': ssh_string
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* 's': char * (C string, pushed as SSH string)
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* 'P': size_t, void * (len of data, pointer to data)
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* only pushes data.
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* 'S': bignum (pushed as SSH string)
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* @returns SSH_OK on success
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* SSH_ERROR on error
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* @warning when using 'P' with a constant size (e.g. 8), do not
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* forget to cast to (size_t).
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*/
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int ssh_buffer_pack(struct ssh_buffer_struct *buffer, const char *format, ...){
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va_list ap;
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int rc;
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va_start(ap, format);
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rc = ssh_buffer_pack_va(buffer, format, ap);
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va_end(ap);
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return rc;
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}
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/** @internal
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* @brief Get multiple values from a buffer on a single function call
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* @param[in] buffer The buffer to get from
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* @param[in] format A format string of arguments.
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* @param[in] ap A va_list of arguments.
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* @returns SSH_OK on success
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* SSH_ERROR on error
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* @see ssh_buffer_get_format() for format list values.
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*/
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int ssh_buffer_unpack_va(struct ssh_buffer_struct *buffer, const char *format, va_list ap){
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int rc;
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const char *p, *last;
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union {
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uint8_t *byte;
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uint16_t *word;
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uint32_t *dword;
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uint64_t *qword;
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ssh_string *string;
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char **cstring;
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void **data;
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} o;
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size_t len, rlen;
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uint32_t u32len;
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va_list ap_copy;
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/* copy the argument list in case a rollback is needed */
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va_copy(ap_copy, ap);
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for (p = format; *p != '\0'; p++) {
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switch (*p) {
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case 'b':
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o.byte = va_arg(ap, uint8_t *);
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rlen = buffer_get_u8(buffer, o.byte);
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rc = rlen==1 ? SSH_OK : SSH_ERROR;
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break;
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case 'w':
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o.word = va_arg(ap, uint16_t *);
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rlen = buffer_get_data(buffer, o.word, sizeof(uint16_t));
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*o.word = ntohs(*o.word);
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rc = rlen==2 ? SSH_OK : SSH_ERROR;
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break;
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case 'd':
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o.dword = va_arg(ap, uint32_t *);
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rlen = buffer_get_u32(buffer, o.dword);
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*o.dword = ntohl(*o.dword);
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rc = rlen==4 ? SSH_OK : SSH_ERROR;
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break;
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case 'q':
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o.qword = va_arg(ap, uint64_t*);
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rlen = buffer_get_u64(buffer, o.qword);
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*o.qword = ntohll(*o.qword);
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rc = rlen==8 ? SSH_OK : SSH_ERROR;
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break;
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case 'S':
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o.string = va_arg(ap, ssh_string *);
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*o.string = buffer_get_ssh_string(buffer);
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rc = *o.string != NULL ? SSH_OK : SSH_ERROR;
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o.string = NULL;
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break;
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case 's':
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o.cstring = va_arg(ap, char **);
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*o.cstring = NULL;
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rc = buffer_get_u32(buffer, &u32len);
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if (rc != 4){
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rc = SSH_ERROR;
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break;
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}
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len = ntohl(u32len);
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if (len > UINT_MAX - 1){
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rc = SSH_ERROR;
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break;
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}
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*o.cstring = malloc(len + 1);
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if (*o.cstring == NULL){
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rc = SSH_ERROR;
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break;
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}
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rlen = buffer_get_data(buffer, *o.cstring, len);
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if (rlen != len){
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SAFE_FREE(*o.cstring);
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rc = SSH_ERROR;
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break;
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}
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(*o.cstring)[len] = '\0';
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o.cstring = NULL;
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rc = SSH_OK;
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break;
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case 'P':
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len = va_arg(ap, size_t);
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o.data = va_arg(ap, void **);
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*o.data = malloc(len);
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if(*o.data == NULL){
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rc = SSH_ERROR;
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break;
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}
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rlen = buffer_get_data(buffer, *o.data, len);
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if (rlen != len){
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SAFE_FREE(*o.data);
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rc = SSH_ERROR;
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break;
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}
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o.data = NULL;
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rc = SSH_OK;
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break;
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default:
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SSH_LOG(SSH_LOG_WARN, "Invalid buffer format %c", *p);
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rc = SSH_ERROR;
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}
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if (rc != SSH_OK) {
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break;
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}
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}
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if (rc != SSH_OK){
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/* Reset the format string and erase everything that was allocated */
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last = p;
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for(p=format;p<last;++p){
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switch(*p){
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case 'b':
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case 'w':
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case 'd':
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case 'q':
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va_arg(ap_copy, void *);
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break;
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case 'S':
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o.string=va_arg(ap_copy, ssh_string *);
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SAFE_FREE(*o.string);
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break;
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case 's':
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o.cstring=va_arg(ap_copy, char **);
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SAFE_FREE(*o.cstring);
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break;
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case 'P':
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va_arg(ap_copy, size_t);
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o.data = va_arg(ap_copy, void **);
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SAFE_FREE(*o.data);
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break;
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default:
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va_arg(ap_copy, void *);
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break;
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}
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}
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}
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va_end(ap_copy);
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return rc;
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}
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/** @internal
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* @brief Get multiple values from a buffer on a single function call
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* @param[in] buffer The buffer to get from
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* @param[in] format A format string of arguments. This string contains single
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* letters describing the order and type of arguments:
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* 'b': uint8_t * (pulled in network byte order)
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* 'w': uint16_t * (pulled in network byte order)
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* 'd': uint32_t * (pulled in network byte order)
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* 'q': uint64_t * (pulled in network byte order)
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* 'S': ssh_string *
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* 's': char ** (C string, pulled as SSH string)
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* 'P': size_t, void ** (len of data, pointer to data)
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* only pulls data.
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* @returns SSH_OK on success
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* SSH_ERROR on error
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* @warning when using 'P' with a constant size (e.g. 8), do not
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* forget to cast to (size_t).
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*/
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int ssh_buffer_unpack(struct ssh_buffer_struct *buffer, const char *format, ...){
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va_list ap;
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int rc;
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va_start(ap, format);
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rc = ssh_buffer_unpack_va(buffer, format, ap);
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va_end(ap);
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return rc;
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}
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/** @} */
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/* vim: set ts=4 sw=4 et cindent: */
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