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ftpd: simplify PORT check by assuming IP = peer's IP.

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Should be as safe as before this change.

function                                             old     new   delta
ftpd_main                                           2115    2025     -90
This commit is contained in:
Denis Vlasenko 2009-03-16 19:54:06 +00:00
parent 20c8216897
commit 43bb7bba3b
1 changed files with 27 additions and 1 deletions
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28
networking/ftpd.c
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@ -422,21 +422,42 @@ handle_epsv(void)
free(response); free(response);
} }
/* libbb candidate */
static
len_and_sockaddr* get_peer_lsa(int fd)
{
len_and_sockaddr *lsa;
socklen_t len = 0;
if (getpeername(fd, NULL, &len) != 0)
return NULL;
lsa = xzalloc(LSA_LEN_SIZE + len);
lsa->len = len;
getpeername(fd, &lsa->u.sa, &lsa->len);
return lsa;
}
static void static void
handle_port(void) handle_port(void)
{ {
unsigned port, port_hi; unsigned port, port_hi;
char *raw, *comma; char *raw, *comma;
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
socklen_t peer_ipv4_len; socklen_t peer_ipv4_len;
struct sockaddr_in peer_ipv4; struct sockaddr_in peer_ipv4;
struct in_addr port_ipv4_sin_addr; struct in_addr port_ipv4_sin_addr;
#endif
port_pasv_cleanup(); port_pasv_cleanup();
raw = G.ftp_arg; raw = G.ftp_arg;
/* PORT command format makes sense only over IPv4 */ /* PORT command format makes sense only over IPv4 */
if (!raw || G.local_addr->u.sa.sa_family != AF_INET) { if (!raw
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
|| G.local_addr->u.sa.sa_family != AF_INET
#endif
) {
bail: bail:
cmdio_write_error(FTP_BADCMD); cmdio_write_error(FTP_BADCMD);
return; return;
@ -459,6 +480,7 @@ handle_port(void)
goto bail; goto bail;
port |= port_hi << 8; port |= port_hi << 8;
#ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES
replace_char(raw, ',', '.'); replace_char(raw, ',', '.');
/* We are verifying that PORT's IP matches getpeername(). /* We are verifying that PORT's IP matches getpeername().
@ -477,6 +499,10 @@ handle_port(void)
goto bail; goto bail;
G.port_addr = xdotted2sockaddr(raw, port); G.port_addr = xdotted2sockaddr(raw, port);
#else
G.port_addr = get_peer_lsa(STDIN_FILENO);
set_nport(G.port_addr, port);
#endif
cmdio_write_ok(FTP_PORTOK); cmdio_write_ok(FTP_PORTOK);
} }