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-rw-r--r--lib/util/getaddrinfo.c406
1 files changed, 406 insertions, 0 deletions
diff --git a/lib/util/getaddrinfo.c b/lib/util/getaddrinfo.c
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+/*
+ * Replacement for a missing getaddrinfo.
+ *
+ * This is an implementation of getaddrinfo for systems that don't have one so
+ * that networking code can use a consistent interface without #ifdef. It is
+ * a fairly minimal implementation, with the following limitations:
+ *
+ * - IPv4 support only. IPv6 is not supported.
+ * - AI_ADDRCONFIG is ignored.
+ * - Not thread-safe due to gethostbyname and getservbyname.
+ * - SOCK_DGRAM and SOCK_STREAM only.
+ * - Multiple possible socket types only generate one addrinfo struct.
+ * - Protocol hints aren't used correctly.
+ *
+ * The last four issues could probably be easily remedied, but haven't been
+ * needed to date. Adding IPv6 support isn't worth it; systems with IPv6
+ * support should already have getaddrinfo.
+ *
+ * The canonical version of this file is maintained in the rra-c-util package,
+ * which can be found at <http://www.eyrie.org/~eagle/software/rra-c-util/>.
+ *
+ * Written by Russ Allbery <rra@stanford.edu>
+ *
+ * The authors hereby relinquish any claim to any copyright that they may have
+ * in this work, whether granted under contract or by operation of law or
+ * international treaty, and hereby commit to the public, at large, that they
+ * shall not, at any time in the future, seek to enforce any copyright in this
+ * work against any person or entity, or prevent any person or entity from
+ * copying, publishing, distributing or creating derivative works of this
+ * work.
+ */
+
+#include <config.h>
+
+#ifndef HAVE_GETADDRINFO
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <netdb.h>
+#include <errno.h>
+
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#ifdef NEED_RESOLV_H
+# include <arpa/nameser.h>
+# include <resolv.h>
+#endif /* NEED_RESOLV_H */
+
+#include <sudo_compat.h>
+#include <compat/getaddrinfo.h>
+
+/* We need access to h_errno to map errors from gethostbyname. */
+#ifndef HAVE_DECL_H_ERRNO
+extern int h_errno;
+#endif
+
+/*
+ * The netdb constants, which aren't always defined (particularly if h_errno
+ * isn't declared). We also make sure that a few of the less-used ones are
+ * defined so that we can deal with them in case statements.
+ */
+#ifndef HOST_NOT_FOUND
+# define HOST_NOT_FOUND 1
+# define TRY_AGAIN 2
+# define NO_RECOVERY 3
+# define NO_DATA 4
+#endif
+#ifndef NETDB_INTERNAL
+# define NETDB_INTERNAL -1
+#endif
+
+/*
+ * If we're running the test suite, rename the functions to avoid conflicts
+ * with the system version. Note that we don't rename the structures and
+ * constants, but that should be okay (except possibly for gai_strerror).
+ */
+#ifdef TESTING
+# define gai_strerror test_gai_strerror
+# define freeaddrinfo test_freeaddrinfo
+# define getaddrinfo test_getaddrinfo
+const char *test_gai_strerror(int);
+void test_freeaddrinfo(struct addrinfo *);
+int test_getaddrinfo(const char *, const char *, const struct addrinfo *,
+ struct addrinfo **);
+#endif
+
+/*
+ * If the platform doesn't support AI_NUMERICSERV or AI_NUMERICHOST,
+ * pick some other values for them.
+ */
+#ifdef TESTING
+# if AI_NUMERICSERV == 0
+# undef AI_NUMERICSERV
+# define AI_NUMERICSERV 0x0080
+# endif
+# if AI_NUMERICHOST == 0
+# undef AI_NUMERICHOST
+# define AI_NUMERICHOST 0x0100
+# endif
+#endif
+
+/*
+ * Value representing all of the hint flags set. Linux uses flags up to
+ * 0x0400, so be sure not to break when testing on that platform.
+ */
+#ifdef TESTING
+# ifdef HAVE_GETADDRINFO
+# define AI_INTERNAL_ALL 0x04ff
+# else
+# define AI_INTERNAL_ALL 0x01ff
+# endif
+#else
+# define AI_INTERNAL_ALL 0x007f
+#endif
+
+/* Table of strings corresponding to the EAI_* error codes. */
+static const char * const gai_errors[] = {
+ "Host name lookup failure", /* 1 EAI_AGAIN */
+ "Invalid flag value", /* 2 EAI_BADFLAGS */
+ "Unknown server error", /* 3 EAI_FAIL */
+ "Unsupported address family", /* 4 EAI_FAMILY */
+ "Memory allocation failure", /* 5 EAI_MEMORY */
+ "Host unknown or not given", /* 6 EAI_NONAME */
+ "Service not supported for socket", /* 7 EAI_SERVICE */
+ "Unsupported socket type", /* 8 EAI_SOCKTYPE */
+ "System error", /* 9 EAI_SYSTEM */
+ "Supplied buffer too small", /* 10 EAI_OVERFLOW */
+};
+
+/* Macro to set the len attribute of sockaddr_in. */
+#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
+# define sin_set_length(s) ((s)->sin_len = sizeof(struct sockaddr_in))
+#else
+# define sin_set_length(s) /* empty */
+#endif
+
+/*
+ * Return a constant string for a given EAI_* error code or a string
+ * indicating an unknown error.
+ */
+const char *
+sudo_gai_strerror(int ecode)
+{
+ if (ecode < 1 || (size_t) ecode > nitems(gai_errors))
+ return "Unknown error";
+ else
+ return gai_errors[ecode - 1];
+}
+
+
+/*
+ * Free a linked list of addrinfo structs.
+ */
+void
+sudo_freeaddrinfo(struct addrinfo *ai)
+{
+ struct addrinfo *next;
+
+ while (ai != NULL) {
+ next = ai->ai_next;
+ if (ai->ai_addr != NULL)
+ free(ai->ai_addr);
+ if (ai->ai_canonname != NULL)
+ free(ai->ai_canonname);
+ free(ai);
+ ai = next;
+ }
+}
+
+
+/*
+ * Allocate a new addrinfo struct, setting some defaults given that this
+ * implementation is IPv4 only. Also allocates an attached sockaddr_in and
+ * zeroes it, per the requirement for getaddrinfo. Takes the socktype,
+ * canonical name (which is copied if not NULL), address, and port. Returns
+ * NULL on a memory allocation failure.
+ */
+static struct addrinfo *
+gai_addrinfo_new(int socktype, const char *canonical, struct in_addr addr,
+ unsigned short port)
+{
+ struct addrinfo *ai;
+
+ ai = malloc(sizeof(*ai));
+ if (ai == NULL)
+ return NULL;
+ ai->ai_addr = malloc(sizeof(struct sockaddr_in));
+ if (ai->ai_addr == NULL) {
+ free(ai);
+ return NULL;
+ }
+ ai->ai_next = NULL;
+ if (canonical == NULL)
+ ai->ai_canonname = NULL;
+ else {
+ ai->ai_canonname = strdup(canonical);
+ if (ai->ai_canonname == NULL) {
+ freeaddrinfo(ai);
+ return NULL;
+ }
+ }
+ memset(ai->ai_addr, 0, sizeof(struct sockaddr_in));
+ ai->ai_flags = 0;
+ ai->ai_family = AF_INET;
+ ai->ai_socktype = socktype;
+ ai->ai_protocol = (socktype == SOCK_DGRAM) ? IPPROTO_UDP : IPPROTO_TCP;
+ ai->ai_addrlen = sizeof(struct sockaddr_in);
+ ((struct sockaddr_in *) ai->ai_addr)->sin_family = AF_INET;
+ ((struct sockaddr_in *) ai->ai_addr)->sin_addr = addr;
+ ((struct sockaddr_in *) ai->ai_addr)->sin_port = htons(port);
+ sin_set_length((struct sockaddr_in *) ai->ai_addr);
+ return ai;
+}
+
+
+/*
+ * Look up a service. Takes the service name (which may be numeric), the hint
+ * flags, a pointer to the socket type (used to determine whether TCP or UDP
+ * services are of interest and, if 0, is filled in with the result of
+ * getservbyname if the service was not numeric), and a pointer to the
+ * addrinfo struct to fill in. Returns 0 on success or an EAI_* error on
+ * failure.
+ */
+static int
+gai_service(const char *servname, int flags, int *type, unsigned short *port)
+{
+ struct servent *servent;
+ const char *protocol;
+ const char *errstr;
+ unsigned short value;
+
+ value = sudo_strtonum(servname, 0, USHRT_MAX, &errstr);
+ if (errstr == NULL) {
+ *port = value;
+ } else if (errno == ERANGE) {
+ return EAI_SERVICE;
+ } else {
+ if (flags & AI_NUMERICSERV)
+ return EAI_NONAME;
+ if (*type != 0)
+ protocol = (*type == SOCK_DGRAM) ? "udp" : "tcp";
+ else
+ protocol = NULL;
+
+ /*
+ * We really technically should be generating an addrinfo struct for
+ * each possible protocol unless type is set, but this works well
+ * enough for what I need this for.
+ */
+ servent = getservbyname(servname, protocol);
+ if (servent == NULL)
+ return EAI_NONAME;
+ if (strcmp(servent->s_proto, "udp") == 0)
+ *type = SOCK_DGRAM;
+ else if (strcmp(servent->s_proto, "tcp") == 0)
+ *type = SOCK_STREAM;
+ else
+ return EAI_SERVICE;
+ *port = htons(servent->s_port);
+ }
+ return 0;
+}
+
+
+/*
+ * Look up a host and fill in a linked list of addrinfo structs with the
+ * results, one per IP address of the returned host. Takes the name or IP
+ * address of the host as a string, the lookup flags, the type of socket (to
+ * fill into the addrinfo structs), the port (likewise), and a pointer to
+ * where the head of the linked list should be put. Returns 0 on success or
+ * the appropriate EAI_* error.
+ */
+static int
+gai_lookup(const char *nodename, int flags, int socktype, unsigned short port,
+ struct addrinfo **res)
+{
+ struct addrinfo *ai, *first, *prev;
+ struct in_addr addr;
+ struct hostent *host;
+ const char *canonical;
+ size_t i;
+
+ if (inet_pton(AF_INET, nodename, &addr)) {
+ canonical = (flags & AI_CANONNAME) ? nodename : NULL;
+ ai = gai_addrinfo_new(socktype, canonical, addr, port);
+ if (ai == NULL)
+ return EAI_MEMORY;
+ *res = ai;
+ return 0;
+ } else {
+ if (flags & AI_NUMERICHOST)
+ return EAI_NONAME;
+ host = gethostbyname(nodename);
+ if (host == NULL)
+ switch (h_errno) {
+ case HOST_NOT_FOUND:
+ return EAI_NONAME;
+ case TRY_AGAIN:
+ case NO_DATA:
+ return EAI_AGAIN;
+ case NO_RECOVERY:
+ return EAI_FAIL;
+ case NETDB_INTERNAL:
+ default:
+ return EAI_SYSTEM;
+ }
+ if (host->h_addr_list[0] == NULL)
+ return EAI_FAIL;
+ canonical = (flags & AI_CANONNAME)
+ ? ((host->h_name != NULL) ? host->h_name : nodename)
+ : NULL;
+ first = NULL;
+ prev = NULL;
+ for (i = 0; host->h_addr_list[i] != NULL; i++) {
+ if (host->h_length != sizeof(addr)) {
+ freeaddrinfo(first);
+ return EAI_FAIL;
+ }
+ memcpy(&addr, host->h_addr_list[i], sizeof(addr));
+ ai = gai_addrinfo_new(socktype, canonical, addr, port);
+ if (ai == NULL) {
+ freeaddrinfo(first);
+ return EAI_MEMORY;
+ }
+ if (first == NULL) {
+ first = ai;
+ prev = ai;
+ } else {
+ prev->ai_next = ai;
+ prev = ai;
+ }
+ }
+ *res = first;
+ return 0;
+ }
+}
+
+
+/*
+ * The actual getaddrinfo implementation.
+ */
+int
+sudo_getaddrinfo(const char *nodename, const char *servname,
+ const struct addrinfo *hints, struct addrinfo **res)
+{
+ struct addrinfo *ai;
+ struct in_addr addr;
+ int flags, socktype, status;
+ unsigned short port;
+
+ /* Take the hints into account and check them for validity. */
+ if (hints != NULL) {
+ flags = hints->ai_flags;
+ socktype = hints->ai_socktype;
+ if ((flags & AI_INTERNAL_ALL) != flags)
+ return EAI_BADFLAGS;
+ if (hints->ai_family != AF_UNSPEC && hints->ai_family != AF_INET)
+ return EAI_FAMILY;
+ if (socktype != 0 && socktype != SOCK_STREAM && socktype != SOCK_DGRAM)
+ return EAI_SOCKTYPE;
+
+ /* EAI_SOCKTYPE isn't quite right, but there isn't anything better. */
+ if (hints->ai_protocol != 0) {
+ int protocol = hints->ai_protocol;
+ if (protocol != IPPROTO_TCP && protocol != IPPROTO_UDP)
+ return EAI_SOCKTYPE;
+ }
+ } else {
+ flags = 0;
+ socktype = 0;
+ }
+
+ /*
+ * See what we're doing. If nodename is null, either AI_PASSIVE is set or
+ * we're getting information for connecting to a service on the loopback
+ * address. Otherwise, we're getting information for connecting to a
+ * remote system.
+ */
+ if (servname == NULL)
+ port = 0;
+ else {
+ status = gai_service(servname, flags, &socktype, &port);
+ if (status != 0)
+ return status;
+ }
+ if (nodename != NULL)
+ return gai_lookup(nodename, flags, socktype, port, res);
+ else {
+ if (servname == NULL)
+ return EAI_NONAME;
+ if ((flags & AI_PASSIVE) == AI_PASSIVE)
+ addr.s_addr = INADDR_ANY;
+ else
+ addr.s_addr = htonl(0x7f000001UL);
+ ai = gai_addrinfo_new(socktype, NULL, addr, port);
+ if (ai == NULL)
+ return EAI_MEMORY;
+ *res = ai;
+ return 0;
+ }
+}
+#endif /* HAVE_GETADDRINFO */
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