Adding upstream version 3.2.7.upstream/3.2.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 538 insertions, 0 deletions

diff --git a/clientname.c b/clientname.c
new file mode 100644
index 0000000..ea94894
--- /dev/null
+++ b/clientname.c
@@ -0,0 +1,538 @@
+/*
+ * Functions for looking up the remote name or addr of a socket.
+ *
+ * Copyright (C) 1992-2001 Andrew Tridgell <tridge@samba.org>
+ * Copyright (C) 2001, 2002 Martin Pool <mbp@samba.org>
+ * Copyright (C) 2002-2022 Wayne Davison
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, visit the http://fsf.org website.
+ */
+
+/*
+ * This file is now converted to use the new-style getaddrinfo()
+ * interface, which supports IPv6 but is also supported on recent
+ * IPv4-only machines.  On systems that don't have that interface, we
+ * emulate it using the KAME implementation.
+ */
+
+#include "rsync.h"
+#include "itypes.h"
+
+extern int am_daemon;
+
+static const char default_name[] = "UNKNOWN";
+static const char proxyv2sig[] = "\r\n\r\n\0\r\nQUIT\n";
+
+static char ipaddr_buf[100];
+
+#define PROXY_V2_SIG_SIZE ((int)sizeof proxyv2sig - 1)
+#define PROXY_V2_HEADER_SIZE (PROXY_V2_SIG_SIZE + 1 + 1 + 2)
+
+#define CMD_LOCAL 0
+#define CMD_PROXY 1
+
+#define PROXY_FAM_TCPv4 0x11
+#define PROXY_FAM_TCPv6 0x21
+
+#define GET_SOCKADDR_FAMILY(ss) ((struct sockaddr*)ss)->sa_family
+
+static void client_sockaddr(int fd, struct sockaddr_storage *ss, socklen_t *ss_len);
+static int check_name(const char *ipaddr, const struct sockaddr_storage *ss, char *name_buf, size_t name_buf_size);
+static int valid_ipaddr(const char *s, int allow_scope);
+
+/* Return the IP addr of the client as a string. */
+char *client_addr(int fd)
+{
+	struct sockaddr_storage ss;
+	socklen_t length = sizeof ss;
+
+	if (*ipaddr_buf)
+		return ipaddr_buf;
+
+	if (am_daemon < 0) {	/* daemon over --rsh mode */
+		char *env_str;
+		strlcpy(ipaddr_buf, "0.0.0.0", sizeof ipaddr_buf);
+		if ((env_str = getenv("REMOTE_HOST")) != NULL
+		 || (env_str = getenv("SSH_CONNECTION")) != NULL
+		 || (env_str = getenv("SSH_CLIENT")) != NULL
+		 || (env_str = getenv("SSH2_CLIENT")) != NULL) {
+			char *p;
+			strlcpy(ipaddr_buf, env_str, sizeof ipaddr_buf);
+			/* Truncate the value to just the IP address. */
+			if ((p = strchr(ipaddr_buf, ' ')) != NULL)
+				*p = '\0';
+		}
+		if (valid_ipaddr(ipaddr_buf, True))
+			return ipaddr_buf;
+	}
+
+	client_sockaddr(fd, &ss, &length);
+	getnameinfo((struct sockaddr *)&ss, length, ipaddr_buf, sizeof ipaddr_buf, NULL, 0, NI_NUMERICHOST);
+
+	return ipaddr_buf;
+}
+
+
+/**
+ * Return the DNS name of the client.
+ *
+ * The name is statically cached so that repeated lookups are quick,
+ * so there is a limit of one lookup per customer.
+ *
+ * If anything goes wrong, including the name->addr->name check, then
+ * we just use "UNKNOWN", so you can use that value in hosts allow
+ * lines.
+ *
+ * After translation from sockaddr to name we do a forward lookup to
+ * make sure nobody is spoofing PTR records.
+ **/
+char *client_name(const char *ipaddr)
+{
+	static char name_buf[100];
+	char port_buf[100];
+	struct sockaddr_storage ss;
+	socklen_t ss_len;
+	struct addrinfo hint, *answer;
+	int err;
+
+	if (*name_buf)
+		return name_buf;
+
+	strlcpy(name_buf, default_name, sizeof name_buf);
+
+	if (strcmp(ipaddr, "0.0.0.0") == 0)
+		return name_buf;
+
+	memset(&ss, 0, sizeof ss);
+	memset(&hint, 0, sizeof hint);
+
+#ifdef AI_NUMERICHOST
+	hint.ai_flags = AI_NUMERICHOST;
+#endif
+	hint.ai_socktype = SOCK_STREAM;
+
+	if ((err = getaddrinfo(ipaddr, NULL, &hint, &answer)) != 0) {
+		rprintf(FLOG, "malformed address %s: %s\n", ipaddr, gai_strerror(err));
+		return name_buf;
+	}
+
+	switch (answer->ai_family) {
+	case AF_INET:
+		ss_len = sizeof (struct sockaddr_in);
+		memcpy(&ss, answer->ai_addr, ss_len);
+		break;
+#ifdef INET6
+	case AF_INET6:
+		ss_len = sizeof (struct sockaddr_in6);
+		memcpy(&ss, answer->ai_addr, ss_len);
+		break;
+#endif
+	default:
+		NOISY_DEATH("Unknown ai_family value");
+	}
+	freeaddrinfo(answer);
+
+	/* reverse lookup */
+	err = getnameinfo((struct sockaddr*)&ss, ss_len, name_buf, sizeof name_buf,
+			  port_buf, sizeof port_buf, NI_NAMEREQD | NI_NUMERICSERV);
+	if (err) {
+		strlcpy(name_buf, default_name, sizeof name_buf);
+		rprintf(FLOG, "name lookup failed for %s: %s\n", ipaddr, gai_strerror(err));
+	} else
+		check_name(ipaddr, &ss, name_buf, sizeof name_buf);
+
+	return name_buf;
+}
+
+
+/* Try to read a proxy protocol header (V1 or V2). Returns 1 on success or 0 on failure. */
+int read_proxy_protocol_header(int fd)
+{
+	union {
+		struct {
+			char line[108];
+		} v1;
+		struct {
+			char sig[PROXY_V2_SIG_SIZE];
+			char ver_cmd;
+			char fam;
+			char len[2];
+			union {
+				struct {
+					char src_addr[4];
+					char dst_addr[4];
+					char src_port[2];
+					char dst_port[2];
+				} ip4;
+				struct {
+					char src_addr[16];
+					char dst_addr[16];
+					char src_port[2];
+					char dst_port[2];
+				} ip6;
+				struct {
+					char src_addr[108];
+					char dst_addr[108];
+				} unx;
+			} addr;
+		} v2;
+	} hdr;
+
+	read_buf(fd, (char*)&hdr, PROXY_V2_SIG_SIZE);
+
+	if (memcmp(hdr.v2.sig, proxyv2sig, PROXY_V2_SIG_SIZE) == 0) { /* Proxy V2 */
+		int ver, cmd, size;
+
+		read_buf(fd, (char*)&hdr + PROXY_V2_SIG_SIZE, PROXY_V2_HEADER_SIZE - PROXY_V2_SIG_SIZE);
+
+		ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
+		cmd = (hdr.v2.ver_cmd & 0x0f);
+		size = (hdr.v2.len[0] << 8) + hdr.v2.len[1];
+
+		if (ver != 2 || size + PROXY_V2_HEADER_SIZE > (int)sizeof hdr)
+			return 0;
+
+		/* Grab all the remaining data in the binary request. */
+		read_buf(fd, (char*)&hdr + PROXY_V2_HEADER_SIZE, size);
+
+		switch (cmd) {
+		case CMD_PROXY:
+			switch (hdr.v2.fam) {
+			case PROXY_FAM_TCPv4:
+				if (size != sizeof hdr.v2.addr.ip4)
+					return 0;
+				inet_ntop(AF_INET, hdr.v2.addr.ip4.src_addr, ipaddr_buf, sizeof ipaddr_buf);
+				return valid_ipaddr(ipaddr_buf, False);
+#ifdef INET6
+			case PROXY_FAM_TCPv6:
+				if (size != sizeof hdr.v2.addr.ip6)
+					return 0;
+				inet_ntop(AF_INET6, hdr.v2.addr.ip6.src_addr, ipaddr_buf, sizeof ipaddr_buf);
+				return valid_ipaddr(ipaddr_buf, False);
+#endif
+			default:
+				break;
+			}
+			/* For an unsupported protocol we'll ignore the proxy data (leaving ipaddr_buf unset)
+			 * and accept the connection, which will get handled as a normal socket addr. */
+			return 1;
+		case CMD_LOCAL:
+			return 1;
+		default:
+			break;
+		}
+
+		return 0;
+	}
+
+	if (memcmp(hdr.v1.line, "PROXY", 5) == 0) { /* Proxy V1 */
+		char *endc, *sp, *p = hdr.v1.line + PROXY_V2_SIG_SIZE;
+		int port_chk;
+
+		*p = '\0';
+		if (!strchr(hdr.v1.line, '\n')) {
+			while (1) {
+				read_buf(fd, p, 1);
+				if (*p++ == '\n')
+					break;
+				if (p - hdr.v1.line >= (int)sizeof hdr.v1.line - 1)
+					return 0;
+			}
+			*p = '\0';
+		}
+
+		endc = strchr(hdr.v1.line, '\r');
+		if (!endc || endc[1] != '\n' || endc[2])
+			return 0;
+		*endc = '\0';
+
+		p = hdr.v1.line + 5;
+
+		if (!isSpace(p++))
+			return 0;
+		if (strncmp(p, "TCP4", 4) == 0)
+			p += 4;
+		else if (strncmp(p, "TCP6", 4) == 0)
+			p += 4;
+		else if (strncmp(p, "UNKNOWN", 7) == 0)
+			return 1;
+		else
+			return 0;
+
+		if (!isSpace(p++))
+			return 0;
+
+		if ((sp = strchr(p, ' ')) == NULL)
+			return 0;
+		*sp = '\0';
+		if (!valid_ipaddr(p, False))
+			return 0;
+		strlcpy(ipaddr_buf, p, sizeof ipaddr_buf); /* It will always fit when valid. */
+
+		p = sp + 1;
+		if ((sp = strchr(p, ' ')) == NULL)
+			return 0;
+		*sp = '\0';
+		if (!valid_ipaddr(p, False))
+			return 0;
+		/* Ignore destination address. */
+
+		p = sp + 1;
+		if ((sp = strchr(p, ' ')) == NULL)
+			return 0;
+		*sp = '\0';
+		port_chk = strtol(p, &endc, 10);
+		if (*endc || port_chk == 0)
+			return 0;
+		/* Ignore source port. */
+
+		p = sp + 1;
+		port_chk = strtol(p, &endc, 10);
+		if (*endc || port_chk == 0)
+			return 0;
+		/* Ignore destination port. */
+
+		return 1;
+	}
+
+	return 0;
+}
+
+
+/**
+ * Get the sockaddr for the client.
+ *
+ * If it comes in as an ipv4 address mapped into IPv6 format then we
+ * convert it back to a regular IPv4.
+ **/
+static void client_sockaddr(int fd, struct sockaddr_storage *ss, socklen_t *ss_len)
+{
+	memset(ss, 0, sizeof *ss);
+
+	if (getpeername(fd, (struct sockaddr *) ss, ss_len)) {
+		/* FIXME: Can we really not continue? */
+		rsyserr(FLOG, errno, "getpeername on fd%d failed", fd);
+		exit_cleanup(RERR_SOCKETIO);
+	}
+
+#ifdef INET6
+	if (GET_SOCKADDR_FAMILY(ss) == AF_INET6
+	 && IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)ss)->sin6_addr)) {
+		/* OK, so ss is in the IPv6 family, but it is really
+		 * an IPv4 address: something like
+		 * "::ffff:10.130.1.2".  If we use it as-is, then the
+		 * reverse lookup might fail or perhaps something else
+		 * bad might happen.  So instead we convert it to an
+		 * equivalent address in the IPv4 address family.  */
+		struct sockaddr_in6 sin6;
+		struct sockaddr_in *sin;
+
+		memcpy(&sin6, ss, sizeof sin6);
+		sin = (struct sockaddr_in *)ss;
+		memset(sin, 0, sizeof *sin);
+		sin->sin_family = AF_INET;
+		*ss_len = sizeof (struct sockaddr_in);
+#ifdef HAVE_SOCKADDR_IN_LEN
+		sin->sin_len = *ss_len;
+#endif
+		sin->sin_port = sin6.sin6_port;
+
+		/* There is a macro to extract the mapped part
+		 * (IN6_V4MAPPED_TO_SINADDR ?), but it does not seem
+		 * to be present in the Linux headers. */
+		memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12], sizeof sin->sin_addr);
+	}
+#endif
+}
+
+
+/**
+ * Compare an addrinfo from the resolver to a sockinfo.
+ *
+ * Like strcmp, returns 0 for identical.
+ **/
+static int compare_addrinfo_sockaddr(const struct addrinfo *ai, const struct sockaddr_storage *ss)
+{
+	int ss_family = GET_SOCKADDR_FAMILY(ss);
+	const char fn[] = "compare_addrinfo_sockaddr";
+
+	if (ai->ai_family != ss_family) {
+		rprintf(FLOG, "%s: response family %d != %d\n",
+			fn, ai->ai_family, ss_family);
+		return 1;
+	}
+
+	/* The comparison method depends on the particular AF. */
+	if (ss_family == AF_INET) {
+		const struct sockaddr_in *sin1, *sin2;
+
+		sin1 = (const struct sockaddr_in *) ss;
+		sin2 = (const struct sockaddr_in *) ai->ai_addr;
+
+		return memcmp(&sin1->sin_addr, &sin2->sin_addr, sizeof sin1->sin_addr);
+	}
+
+#ifdef INET6
+	if (ss_family == AF_INET6) {
+		const struct sockaddr_in6 *sin1, *sin2;
+
+		sin1 = (const struct sockaddr_in6 *) ss;
+		sin2 = (const struct sockaddr_in6 *) ai->ai_addr;
+
+		if (ai->ai_addrlen < (int)sizeof (struct sockaddr_in6)) {
+			rprintf(FLOG, "%s: too short sockaddr_in6; length=%d\n",
+				fn, (int)ai->ai_addrlen);
+			return 1;
+		}
+
+		if (memcmp(&sin1->sin6_addr, &sin2->sin6_addr, sizeof sin1->sin6_addr))
+			return 1;
+
+#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
+		if (sin1->sin6_scope_id != sin2->sin6_scope_id)
+			return 1;
+#endif
+		return 0;
+	}
+#endif /* INET6 */
+
+	/* don't know */
+	return 1;
+}
+
+
+/**
+ * Do a forward lookup on @p name_buf and make sure it corresponds to
+ * @p ss -- otherwise we may be being spoofed.  If we suspect we are,
+ * then we don't abort the connection but just emit a warning, and
+ * change @p name_buf to be "UNKNOWN".
+ *
+ * We don't do anything with the service when checking the name,
+ * because it doesn't seem that it could be spoofed in any way, and
+ * getaddrinfo on random service names seems to cause problems on AIX.
+ **/
+static int check_name(const char *ipaddr, const struct sockaddr_storage *ss, char *name_buf, size_t name_buf_size)
+{
+	struct addrinfo hints, *res, *res0;
+	int error;
+	int ss_family = GET_SOCKADDR_FAMILY(ss);
+
+	memset(&hints, 0, sizeof hints);
+	hints.ai_family = ss_family;
+	hints.ai_flags = AI_CANONNAME;
+	hints.ai_socktype = SOCK_STREAM;
+	error = getaddrinfo(name_buf, NULL, &hints, &res0);
+	if (error) {
+		rprintf(FLOG, "forward name lookup for %s failed: %s\n",
+			name_buf, gai_strerror(error));
+		strlcpy(name_buf, default_name, name_buf_size);
+		return error;
+	}
+
+	/* Given all these results, we expect that one of them will be
+	 * the same as ss.  The comparison is a bit complicated. */
+	for (res = res0; res; res = res->ai_next) {
+		if (!compare_addrinfo_sockaddr(res, ss))
+			break;	/* OK, identical */
+	}
+
+	if (!res0) {
+		/* We hit the end of the list without finding an
+		 * address that was the same as ss. */
+		rprintf(FLOG, "no known address for \"%s\": "
+			"spoofed address?\n", name_buf);
+		strlcpy(name_buf, default_name, name_buf_size);
+	} else if (res == NULL) {
+		/* We hit the end of the list without finding an
+		 * address that was the same as ss. */
+		rprintf(FLOG, "%s is not a known address for \"%s\": "
+			"spoofed address?\n", ipaddr, name_buf);
+		strlcpy(name_buf, default_name, name_buf_size);
+	}
+
+	freeaddrinfo(res0);
+	return 0;
+}
+
+/* Returns 1 for a valid IPv4 or IPv6 addr, or 0 for a bad one. */
+static int valid_ipaddr(const char *s, int allow_scope)
+{
+	int i;
+
+	if (strchr(s, ':') != NULL) { /* Only IPv6 has a colon. */
+		int count, saw_double_colon = 0;
+		int ipv4_at_end = 0;
+
+		if (*s == ':') { /* A colon at the start must be a :: */
+			if (*++s != ':')
+				return 0;
+			saw_double_colon = 1;
+			s++;
+		}
+
+		for (count = 0; count < 8; count++) {
+			if (!*s)
+				return saw_double_colon;
+			if (allow_scope && *s == '%') {
+				if (saw_double_colon)
+					break;
+				return 0;
+			}
+
+			if (strchr(s, ':') == NULL && strchr(s, '.') != NULL) {
+				if ((!saw_double_colon && count != 6) || (saw_double_colon && count > 6))
+					return 0;
+				ipv4_at_end = 1;
+				break;
+			}
+
+			if (!isHexDigit(s++)) /* Need 1-4 hex digits */
+				return 0;
+			if (isHexDigit(s) && isHexDigit(++s) && isHexDigit(++s) && isHexDigit(++s))
+				return 0;
+
+			if (*s == ':') {
+				if (!*++s)
+					return 0;
+				if (*s == ':') {
+					if (saw_double_colon)
+						return 0;
+					saw_double_colon = 1;
+					s++;
+				}
+			}
+		}
+
+		if (!ipv4_at_end) {
+			if (allow_scope && *s == '%')
+				for (s++; isAlNum(s); s++) { }
+			return !*s && s[-1] != '%';
+		}
+	}
+
+	/* IPv4 */
+	for (i = 0; i < 4; i++) {
+		long n;
+		char *end;
+
+		if (i && *s++ != '.')
+			return 0;
+		n = strtol(s, &end, 10);
+		if (n > 255 || n < 0 || end <= s || end > s+3)
+			return 0;
+		s = end;
+	}
+
+	return !*s;
+}