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keyb-interactive: allow zero length fields

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Allow zero length fields so they don't cause malloc(0) calls

Avoid free()ing NULL pointers

Avoid a malloc of a fixed 5 byte buffer.
This commit is contained in:
Daniel Stenberg
2011-05-31 23:33:56 +02:00
parent 0723dab4d7
commit 566894494b
1 changed files with 81 additions and 79 deletions
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40
src/userauth.c
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@@ -1447,7 +1447,6 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
}
/* server requested PAM-like conversation */
s = session->userauth_kybd_data + 1;
/* string name (ISO-10646 UTF-8) */
@@ -1472,6 +1471,7 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
/* string instruction (ISO-10646 UTF-8) */
session->userauth_kybd_auth_instruction_len = _libssh2_ntohu32(s);
s += 4;
if(session->userauth_kybd_auth_instruction_len) {
session->userauth_kybd_auth_instruction =
LIBSSH2_ALLOC(session,
session->userauth_kybd_auth_instruction_len);
@@ -1485,10 +1485,12 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
memcpy(session->userauth_kybd_auth_instruction, s,
session->userauth_kybd_auth_instruction_len);
s += session->userauth_kybd_auth_instruction_len;
}
/* string language tag (as defined in [RFC-3066]) */
language_tag_len = _libssh2_ntohu32(s);
s += 4;
/* ignoring this field as deprecated */
s += language_tag_len;
@@ -1496,6 +1498,7 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
session->userauth_kybd_num_prompts = _libssh2_ntohu32(s);
s += 4;
if(session->userauth_kybd_num_prompts) {
session->userauth_kybd_prompts =
LIBSSH2_ALLOC(session,
sizeof(LIBSSH2_USERAUTH_KBDINT_PROMPT) *
@@ -1526,7 +1529,8 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
for(i = 0; i != session->userauth_kybd_num_prompts; ++i) {
/* string prompt[1] (ISO-10646 UTF-8) */
session->userauth_kybd_prompts[i].length = _libssh2_ntohu32(s);
session->userauth_kybd_prompts[i].length =
_libssh2_ntohu32(s);
s += 4;
session->userauth_kybd_prompts[i].text =
LIBSSH2_ALLOC(session,
@@ -1544,6 +1548,7 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
/* boolean echo[1] */
session->userauth_kybd_prompts[i].echo = *s++;
}
}
response_callback(session->userauth_kybd_auth_name,
session->userauth_kybd_auth_name_len,
@@ -1558,11 +1563,6 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
"Keyboard-interactive response callback function"
" invoked");
session->userauth_kybd_packet_len =
1 /* byte SSH_MSG_USERAUTH_INFO_RESPONSE */
+ 4 /* int num-responses */
;
for(i = 0; i != session->userauth_kybd_num_prompts; ++i) {
/* string response[1] (ISO-10646 UTF-8) */
session->userauth_kybd_packet_len +=
@@ -1572,15 +1572,10 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
/* A new userauth_kybd_data area is to be allocated, free the
former one. */
LIBSSH2_FREE(session, session->userauth_kybd_data);
session->userauth_kybd_data = NULL;
session->userauth_kybd_data = s =
LIBSSH2_ALLOC(session, session->userauth_kybd_packet_len);
if (!s) {
_libssh2_error(session, LIBSSH2_ERROR_ALLOC,
"Unable to allocate memory for keyboard-"
"interactive response packet");
goto cleanup;
}
/* get a pointer to the storage buffer that fits 5 bytes */
s = &session->userauth_buf[0];
*s = SSH_MSG_USERAUTH_INFO_RESPONSE;
s++;
@@ -1596,13 +1591,12 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
}
if (session->userauth_kybd_state == libssh2_NB_state_sent1) {
rc = _libssh2_transport_send(session, session->userauth_kybd_data,
session->userauth_kybd_packet_len,
rc = _libssh2_transport_send(session, session->userauth_buf,
sizeof(session->userauth_buf),
NULL, 0);
if (rc == LIBSSH2_ERROR_EAGAIN) {
if (rc == LIBSSH2_ERROR_EAGAIN)
return _libssh2_error(session, LIBSSH2_ERROR_EAGAIN,
"Would block");
}
if (rc) {
_libssh2_error(session, LIBSSH2_ERROR_SOCKET_SEND,
"Unable to send userauth-keyboard-interactive"
@@ -1637,14 +1631,22 @@ userauth_keyboard_interactive(LIBSSH2_SESSION * session,
}
}
if(session->userauth_kybd_prompts) {
LIBSSH2_FREE(session, session->userauth_kybd_prompts);
session->userauth_kybd_prompts = NULL;
}
if(session->userauth_kybd_responses) {
LIBSSH2_FREE(session, session->userauth_kybd_responses);
session->userauth_kybd_responses = NULL;
}
if(session->userauth_kybd_auth_name) {
LIBSSH2_FREE(session, session->userauth_kybd_auth_name);
session->userauth_kybd_auth_name = NULL;
}
if(session->userauth_kybd_auth_instruction) {
LIBSSH2_FREE(session, session->userauth_kybd_auth_instruction);
session->userauth_kybd_auth_instruction = NULL;
}
if (session->userauth_kybd_auth_failure) {
session->userauth_kybd_state = libssh2_NB_state_idle;