Date: Wed, 09 Sep 2015 05:30:03 +0900 (JST) From: Hiroki Sato <hrs@FreeBSD.org> To: net@FreeBSD.org Subject: PF_LOCAL support in getaddrinfo/getnameinfo Message-ID: <20150909.053003.1234482271945809368.hrs@allbsd.org>
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Hi,
Is there any problem with adding PF_LOCAL support into getaddrinfo()
and getnameinfo()? It was not standardized but can be implemented
in a straight forward way (attached).
Some old posts in mailing list archives (not for FreeBSD) said it was
removed in glibc due to a security issue that getaddrinfo() call with
PF_UNSPEC could create /tmp/<hostname> unintentionally when no
hostname was resolved. IIRC KAME's original implementation included
this functionality, but I am not sure of why it was removed. Does
anyone know the reason, or other potential problems?
In the attached patch PF_LOCAL is not used when getaddrinfo() is
called with PF_UNSPEC, and only an absolute pathname is accepted.
This should not have a bad side-effect for the existing programs
which use them.
-- Hiroki
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Index: lib/libc/net/getaddrinfo.c
===================================================================
--- lib/libc/net/getaddrinfo.c (revision 287348)
+++ lib/libc/net/getaddrinfo.c (working copy)
@@ -137,13 +137,19 @@
offsetof(struct sockaddr_in6, sin6_addr),
in6_addrany, in6_loopback, 1},
#define N_INET 1
+#define N_LOCAL 2
#else
#define N_INET 0
+#define N_LOCAL 1
#endif
{PF_INET, sizeof(struct in_addr),
sizeof(struct sockaddr_in),
offsetof(struct sockaddr_in, sin_addr),
in_addrany, in_loopback, 0},
+ {PF_LOCAL, sizeof(char[104]),
+ sizeof(struct sockaddr_un),
+ offsetof(struct sockaddr_un, sun_path),
+ NULL, NULL, 0},
{0, 0, 0, 0, NULL, NULL, 0},
};
@@ -158,9 +164,9 @@
};
static const struct explore explore[] = {
-#if 0
- { PF_LOCAL, ANY, ANY, 0x01 },
-#endif
+ { PF_LOCAL, SOCK_DGRAM, ANY, 0x04 },
+ { PF_LOCAL, SOCK_STREAM, ANY, 0x04 },
+ { PF_LOCAL, SOCK_SEQPACKET, ANY, 0x04 },
#ifdef INET6
{ PF_INET6, SOCK_DGRAM, IPPROTO_UDP, 0x07 },
{ PF_INET6, SOCK_STREAM, IPPROTO_TCP, 0x07 },
@@ -408,6 +414,7 @@
ERR(EAI_BADFLAGS);
switch (hints->ai_family) {
case PF_UNSPEC:
+ case PF_LOCAL:
case PF_INET:
#ifdef INET6
case PF_INET6:
@@ -1130,6 +1137,9 @@
*res = NULL;
ai = NULL;
+ if (pai->ai_family == PF_LOCAL)
+ return (0);
+
/*
* filter out AFs that are not supported by the kernel
* XXX errno?
@@ -1172,7 +1182,7 @@
const struct afd *afd;
struct addrinfo *ai;
int error;
- char pton[PTON_MAX];
+ char pton[PTON_MAX], path[PATH_MAX], *p;
*res = NULL;
ai = NULL;
@@ -1182,6 +1192,15 @@
return 0;
switch (afd->a_af) {
+ case AF_LOCAL:
+ if (hostname[0] != '/')
+ ERR(EAI_FAIL);
+ if (strlen(hostname) > afd->a_addrlen)
+ ERR(EAI_MEMORY);
+ /* NUL-termination does not need to be guaranteed. */
+ strncpy(path, hostname, afd->a_addrlen);
+ p = &path[0];
+ break;
case AF_INET:
/*
* RFC3493 requires getaddrinfo() to accept AF_INET formats
@@ -1192,15 +1211,17 @@
*/
if (inet_aton(hostname, (struct in_addr *)pton) != 1)
return 0;
+ p = pton;
break;
default:
if (inet_pton(afd->a_af, hostname, pton) != 1)
return 0;
+ p = pton;
break;
}
if (pai->ai_family == afd->a_af) {
- GET_AI(ai, afd, pton);
+ GET_AI(ai, afd, p);
GET_PORT(ai, servname);
if ((pai->ai_flags & AI_CANONNAME)) {
/*
@@ -1320,6 +1341,12 @@
memset(ai->ai_addr, 0, (size_t)afd->a_socklen);
ai->ai_addr->sa_len = afd->a_socklen;
ai->ai_addrlen = afd->a_socklen;
+ if (ai->ai_family == PF_LOCAL) {
+ size_t n = strlen(addr);
+
+ ai->ai_addrlen -= afd->a_addrlen - n;
+ ai->ai_addr->sa_len -= afd->a_addrlen - n;
+ }
ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
p = (char *)(void *)(ai->ai_addr);
memcpy(p + afd->a_off, addr, (size_t)afd->a_addrlen);
Index: lib/libc/net/getnameinfo.c
===================================================================
--- lib/libc/net/getnameinfo.c (revision 287404)
+++ lib/libc/net/getnameinfo.c (working copy)
@@ -49,6 +49,7 @@
#include <sys/types.h>
#include <sys/socket.h>
+#include <sys/un.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
@@ -72,6 +73,8 @@
static int getnameinfo_link(const struct sockaddr *, socklen_t, char *,
size_t, char *, size_t, int);
static int hexname(const u_int8_t *, size_t, char *, size_t);
+static int getnameinfo_un(const struct sockaddr *, socklen_t, char *,
+ size_t, char *, size_t, int);
int
getnameinfo(const struct sockaddr *sa, socklen_t salen,
@@ -89,6 +92,9 @@
case AF_LINK:
return getnameinfo_link(sa, salen, host, hostlen, serv,
servlen, flags);
+ case AF_LOCAL:
+ return getnameinfo_un(sa, salen, host, hostlen, serv,
+ servlen, flags);
default:
return EAI_FAMILY;
}
@@ -106,6 +112,8 @@
#endif
{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
offsetof(struct sockaddr_in, sin_addr)},
+ {PF_LOCAL, sizeof(char[104]), sizeof(struct sockaddr_un),
+ offsetof(struct sockaddr_un, sun_path)},
{0, 0, 0},
};
@@ -469,3 +477,39 @@
}
return 0;
}
+
+/*
+ * getnameinfo_un():
+ * Format a pathname of UNIX IPC domain socket.
+ */
+/* ARGSUSED */
+static int
+getnameinfo_un(const struct sockaddr *sa, socklen_t salen,
+ char *host, size_t hostlen, char *serv, size_t servlen, int flags)
+{
+ const struct afd *afd;
+ size_t pathlen;
+ const char *addr;
+
+ for (afd = &afdl[0]; afd != NULL; afd++) {
+ if (afd->a_af == AF_LOCAL)
+ break;
+ }
+ if (afd == NULL)
+ return (EAI_FAIL);
+
+ if (serv != NULL && servlen > 0)
+ *serv = '\0';
+
+ pathlen = sa->sa_len - afd->a_off;
+ addr = (const char *)sa + afd->a_off;
+
+ if (pathlen + 1 > hostlen) {
+ *host = '\0';
+ return (EAI_MEMORY);
+ }
+ memcpy(host, addr, pathlen);
+ host[pathlen] = '\0';
+
+ return (0);
+}
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