view src/core/ngx_proxy_protocol.c @ 7623:72b792bb3885

HTTP/2: fixed socket leak with an incomplete HEADERS frame. A connection could get stuck without timers if a client has partially sent the HEADERS frame such that it was split on the individual header boundary. In this case, it cannot be processed without the rest of the HEADERS frame. The fix is to call ngx_http_v2_state_headers_save() in this case. Normally, it would be called from the ngx_http_v2_state_header_block() handler on the next iteration, when there is not enough data to continue processing. This isn't the case if recv_buffer became empty and there's no more data to read.
author Sergey Kandaurov <pluknet@nginx.com>
date Wed, 05 Feb 2020 16:29:23 +0300
parents 89adf49fe76a
children 017fd847f4f7
line wrap: on
line source


/*
 * Copyright (C) Roman Arutyunyan
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


#define NGX_PROXY_PROTOCOL_AF_INET          1
#define NGX_PROXY_PROTOCOL_AF_INET6         2


#define ngx_proxy_protocol_parse_uint16(p)  ((p)[0] << 8 | (p)[1])


typedef struct {
    u_char                                  signature[12];
    u_char                                  version_command;
    u_char                                  family_transport;
    u_char                                  len[2];
} ngx_proxy_protocol_header_t;


typedef struct {
    u_char                                  src_addr[4];
    u_char                                  dst_addr[4];
    u_char                                  src_port[2];
    u_char                                  dst_port[2];
} ngx_proxy_protocol_inet_addrs_t;


typedef struct {
    u_char                                  src_addr[16];
    u_char                                  dst_addr[16];
    u_char                                  src_port[2];
    u_char                                  dst_port[2];
} ngx_proxy_protocol_inet6_addrs_t;


static u_char *ngx_proxy_protocol_read_addr(ngx_connection_t *c, u_char *p,
    u_char *last, ngx_str_t *addr);
static u_char *ngx_proxy_protocol_read_port(u_char *p, u_char *last,
    in_port_t *port, u_char sep);
static u_char *ngx_proxy_protocol_v2_read(ngx_connection_t *c, u_char *buf,
    u_char *last);


u_char *
ngx_proxy_protocol_read(ngx_connection_t *c, u_char *buf, u_char *last)
{
    size_t                 len;
    u_char                *p;
    ngx_proxy_protocol_t  *pp;

    static const u_char signature[] = "\r\n\r\n\0\r\nQUIT\n";

    p = buf;
    len = last - buf;

    if (len >= sizeof(ngx_proxy_protocol_header_t)
        && memcmp(p, signature, sizeof(signature) - 1) == 0)
    {
        return ngx_proxy_protocol_v2_read(c, buf, last);
    }

    if (len < 8 || ngx_strncmp(p, "PROXY ", 6) != 0) {
        goto invalid;
    }

    p += 6;
    len -= 6;

    if (len >= 7 && ngx_strncmp(p, "UNKNOWN", 7) == 0) {
        ngx_log_debug0(NGX_LOG_DEBUG_CORE, c->log, 0,
                       "PROXY protocol unknown protocol");
        p += 7;
        goto skip;
    }

    if (len < 5 || ngx_strncmp(p, "TCP", 3) != 0
        || (p[3] != '4' && p[3] != '6') || p[4] != ' ')
    {
        goto invalid;
    }

    p += 5;

    pp = ngx_pcalloc(c->pool, sizeof(ngx_proxy_protocol_t));
    if (pp == NULL) {
        return NULL;
    }

    p = ngx_proxy_protocol_read_addr(c, p, last, &pp->src_addr);
    if (p == NULL) {
        goto invalid;
    }

    p = ngx_proxy_protocol_read_addr(c, p, last, &pp->dst_addr);
    if (p == NULL) {
        goto invalid;
    }

    p = ngx_proxy_protocol_read_port(p, last, &pp->src_port, ' ');
    if (p == NULL) {
        goto invalid;
    }

    p = ngx_proxy_protocol_read_port(p, last, &pp->dst_port, CR);
    if (p == NULL) {
        goto invalid;
    }

    if (p == last) {
        goto invalid;
    }

    if (*p++ != LF) {
        goto invalid;
    }

    ngx_log_debug4(NGX_LOG_DEBUG_CORE, c->log, 0,
                   "PROXY protocol src: %V %d, dst: %V %d",
                   &pp->src_addr, pp->src_port, &pp->dst_addr, pp->dst_port);

    c->proxy_protocol = pp;

    return p;

skip:

    for ( /* void */ ; p < last - 1; p++) {
        if (p[0] == CR && p[1] == LF) {
            return p + 2;
        }
    }

invalid:

    ngx_log_error(NGX_LOG_ERR, c->log, 0,
                  "broken header: \"%*s\"", (size_t) (last - buf), buf);

    return NULL;
}


static u_char *
ngx_proxy_protocol_read_addr(ngx_connection_t *c, u_char *p, u_char *last,
    ngx_str_t *addr)
{
    size_t  len;
    u_char  ch, *pos;

    pos = p;

    for ( ;; ) {
        if (p == last) {
            return NULL;
        }

        ch = *p++;

        if (ch == ' ') {
            break;
        }

        if (ch != ':' && ch != '.'
            && (ch < 'a' || ch > 'f')
            && (ch < 'A' || ch > 'F')
            && (ch < '0' || ch > '9'))
        {
            return NULL;
        }
    }

    len = p - pos - 1;

    addr->data = ngx_pnalloc(c->pool, len);
    if (addr->data == NULL) {
        return NULL;
    }

    ngx_memcpy(addr->data, pos, len);
    addr->len = len;

    return p;
}


static u_char *
ngx_proxy_protocol_read_port(u_char *p, u_char *last, in_port_t *port,
    u_char sep)
{
    size_t      len;
    u_char     *pos;
    ngx_int_t   n;

    pos = p;

    for ( ;; ) {
        if (p == last) {
            return NULL;
        }

        if (*p++ == sep) {
            break;
        }
    }

    len = p - pos - 1;

    n = ngx_atoi(pos, len);
    if (n < 0 || n > 65535) {
        return NULL;
    }

    *port = (in_port_t) n;

    return p;
}


u_char *
ngx_proxy_protocol_write(ngx_connection_t *c, u_char *buf, u_char *last)
{
    ngx_uint_t  port, lport;

    if (last - buf < NGX_PROXY_PROTOCOL_MAX_HEADER) {
        return NULL;
    }

    if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) {
        return NULL;
    }

    switch (c->sockaddr->sa_family) {

    case AF_INET:
        buf = ngx_cpymem(buf, "PROXY TCP4 ", sizeof("PROXY TCP4 ") - 1);
        break;

#if (NGX_HAVE_INET6)
    case AF_INET6:
        buf = ngx_cpymem(buf, "PROXY TCP6 ", sizeof("PROXY TCP6 ") - 1);
        break;
#endif

    default:
        return ngx_cpymem(buf, "PROXY UNKNOWN" CRLF,
                          sizeof("PROXY UNKNOWN" CRLF) - 1);
    }

    buf += ngx_sock_ntop(c->sockaddr, c->socklen, buf, last - buf, 0);

    *buf++ = ' ';

    buf += ngx_sock_ntop(c->local_sockaddr, c->local_socklen, buf, last - buf,
                         0);

    port = ngx_inet_get_port(c->sockaddr);
    lport = ngx_inet_get_port(c->local_sockaddr);

    return ngx_slprintf(buf, last, " %ui %ui" CRLF, port, lport);
}


static u_char *
ngx_proxy_protocol_v2_read(ngx_connection_t *c, u_char *buf, u_char *last)
{
    u_char                             *end;
    size_t                              len;
    socklen_t                           socklen;
    ngx_uint_t                          version, command, family, transport;
    ngx_sockaddr_t                      src_sockaddr, dst_sockaddr;
    ngx_proxy_protocol_t               *pp;
    ngx_proxy_protocol_header_t        *header;
    ngx_proxy_protocol_inet_addrs_t    *in;
#if (NGX_HAVE_INET6)
    ngx_proxy_protocol_inet6_addrs_t   *in6;
#endif

    header = (ngx_proxy_protocol_header_t *) buf;

    buf += sizeof(ngx_proxy_protocol_header_t);

    version = header->version_command >> 4;

    if (version != 2) {
        ngx_log_error(NGX_LOG_ERR, c->log, 0,
                      "unknown PROXY protocol version: %ui", version);
        return NULL;
    }

    len = ngx_proxy_protocol_parse_uint16(header->len);

    if ((size_t) (last - buf) < len) {
        ngx_log_error(NGX_LOG_ERR, c->log, 0, "header is too large");
        return NULL;
    }

    end = buf + len;

    command = header->version_command & 0x0f;

    /* only PROXY is supported */
    if (command != 1) {
        ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
                       "PROXY protocol v2 unsupported command %ui", command);
        return end;
    }

    transport = header->family_transport & 0x0f;

    /* only STREAM is supported */
    if (transport != 1) {
        ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
                       "PROXY protocol v2 unsupported transport %ui",
                       transport);
        return end;
    }

    pp = ngx_pcalloc(c->pool, sizeof(ngx_proxy_protocol_t));
    if (pp == NULL) {
        return NULL;
    }

    family = header->family_transport >> 4;

    switch (family) {

    case NGX_PROXY_PROTOCOL_AF_INET:

        if ((size_t) (end - buf) < sizeof(ngx_proxy_protocol_inet_addrs_t)) {
            return NULL;
        }

        in = (ngx_proxy_protocol_inet_addrs_t *) buf;

        src_sockaddr.sockaddr_in.sin_family = AF_INET;
        src_sockaddr.sockaddr_in.sin_port = 0;
        memcpy(&src_sockaddr.sockaddr_in.sin_addr, in->src_addr, 4);

        dst_sockaddr.sockaddr_in.sin_family = AF_INET;
        dst_sockaddr.sockaddr_in.sin_port = 0;
        memcpy(&dst_sockaddr.sockaddr_in.sin_addr, in->dst_addr, 4);

        pp->src_port = ngx_proxy_protocol_parse_uint16(in->src_port);
        pp->dst_port = ngx_proxy_protocol_parse_uint16(in->dst_port);

        socklen = sizeof(struct sockaddr_in);

        buf += sizeof(ngx_proxy_protocol_inet_addrs_t);

        break;

#if (NGX_HAVE_INET6)

    case NGX_PROXY_PROTOCOL_AF_INET6:

        if ((size_t) (end - buf) < sizeof(ngx_proxy_protocol_inet6_addrs_t)) {
            return NULL;
        }

        in6 = (ngx_proxy_protocol_inet6_addrs_t *) buf;

        src_sockaddr.sockaddr_in6.sin6_family = AF_INET6;
        src_sockaddr.sockaddr_in6.sin6_port = 0;
        memcpy(&src_sockaddr.sockaddr_in6.sin6_addr, in6->src_addr, 16);

        dst_sockaddr.sockaddr_in6.sin6_family = AF_INET6;
        dst_sockaddr.sockaddr_in6.sin6_port = 0;
        memcpy(&dst_sockaddr.sockaddr_in6.sin6_addr, in6->dst_addr, 16);

        pp->src_port = ngx_proxy_protocol_parse_uint16(in6->src_port);
        pp->dst_port = ngx_proxy_protocol_parse_uint16(in6->dst_port);

        socklen = sizeof(struct sockaddr_in6);

        buf += sizeof(ngx_proxy_protocol_inet6_addrs_t);

        break;

#endif

    default:
        ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
                       "PROXY protocol v2 unsupported address family %ui",
                       family);
        return end;
    }

    pp->src_addr.data = ngx_pnalloc(c->pool, NGX_SOCKADDR_STRLEN);
    if (pp->src_addr.data == NULL) {
        return NULL;
    }

    pp->src_addr.len = ngx_sock_ntop(&src_sockaddr.sockaddr, socklen,
                                     pp->src_addr.data, NGX_SOCKADDR_STRLEN, 0);

    pp->dst_addr.data = ngx_pnalloc(c->pool, NGX_SOCKADDR_STRLEN);
    if (pp->dst_addr.data == NULL) {
        return NULL;
    }

    pp->dst_addr.len = ngx_sock_ntop(&dst_sockaddr.sockaddr, socklen,
                                     pp->dst_addr.data, NGX_SOCKADDR_STRLEN, 0);

    ngx_log_debug4(NGX_LOG_DEBUG_CORE, c->log, 0,
                   "PROXY protocol v2 src: %V %d, dst: %V %d",
                   &pp->src_addr, pp->src_port, &pp->dst_addr, pp->dst_port);

    if (buf < end) {
        ngx_log_debug1(NGX_LOG_DEBUG_CORE, c->log, 0,
                       "PROXY protocol v2 %z bytes of tlv ignored", end - buf);
    }

    c->proxy_protocol = pp;

    return end;
}