43bb7bba3
Denis Vlasenko
2009-03-16
Subject
ftpd: simplify PORT check by assuming IP = peer's IP. Should be as safe as before this change.
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networking/ftpd.c+27 -1
| @@ -422,21 +422,42 @@ handle_epsv(void) | |
| 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 | |
| handle_port(void) | |
| { | |
| unsigned port, port_hi; | |
| char *raw, *comma; | |
| + | #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES |
| socklen_t peer_ipv4_len; | |
| struct sockaddr_in peer_ipv4; | |
| struct in_addr port_ipv4_sin_addr; | |
| + | #endif |
| port_pasv_cleanup(); | |
| raw = G.ftp_arg; | |
| /* 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: | |
| cmdio_write_error(FTP_BADCMD); | |
| return; | |
| @@ -459,6 +480,7 @@ handle_port(void) | |
| goto bail; | |
| port |= port_hi << 8; | |
| + | #ifdef WHY_BOTHER_WE_CAN_ASSUME_IP_MATCHES |
| replace_char(raw, ',', '.'); | |
| /* We are verifying that PORT's IP matches getpeername(). | |
| @@ -477,6 +499,10 @@ handle_port(void) | |
| goto bail; | |
| 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); | |
| } | |