Robustify netlink response parsers

* socketutils.c (inet_parse_response, unix_parse_response): Change
return type from bool to int, return -1 on all parse errors except
inode mismatch.
(receive_responses): Stop on the first nlmsg_type that is not
SOCK_DIAG_BY_FAMILY, also stop when the parser returns -1.
* tests/netlink_inet_diag.c (check_responses): Stop on short messages,
on first nlmsg_type that is not SOCK_DIAG_BY_FAMILY, print more verbose
diagnostics for NLMSG_ERROR.
* tests/netlink_unix_diag.c (check_responses): Likewise.

diff --git a/socketutils.c b/socketutils.c
index aa8216390ab264c9b12e9f3b9f122e3f71ce11f1..6fbb8cfef5a317f93dffc3bc1ec3e8d46b3db168 100644 (file)
--- a/socketutils.c
+++ b/socketutils.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2014 Zubin Mithra <zubin.mithra@gmail.com>
- * Copyright (c) 2014-2015 Dmitry V. Levin <ldv@altlinux.org>
+ * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -71,7 +71,7 @@ inet_send_query(const int fd, const int family, const int proto)
                .iov_len = sizeof(req)
        };
        struct msghdr msg = {
-               .msg_name = (void*)&nladdr,
+               .msg_name = (void *) &nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = &iov,
                .msg_iovlen = 1
@@ -87,18 +87,18 @@ inet_send_query(const int fd, const int family, const int proto)
        }
 }
 
-static bool
-inet_parse_response(const char *proto_name, const void *data, int data_len,
-                   const unsigned long inode)
+static int
+inet_parse_response(const char *proto_name, const void *data,
+                   const int data_len, const unsigned long inode)
 {
        const struct inet_diag_msg *diag_msg = data;
        static const char zero_addr[sizeof(struct in6_addr)];
        socklen_t addr_size, text_size;
 
        if (data_len < (int) NLMSG_LENGTH(sizeof(*diag_msg)))
-               return false;
+               return -1;
        if (diag_msg->idiag_inode != inode)
-               return false;
+               return 0;
 
        switch(diag_msg->idiag_family) {
                case AF_INET:
@@ -110,14 +110,14 @@ inet_parse_response(const char *proto_name, const void *data, int data_len,
                        text_size = INET6_ADDRSTRLEN;
                        break;
                default:
-                       return false;
+                       return -1;
        }
 
        char src_buf[text_size];
 
        if (!inet_ntop(diag_msg->idiag_family, diag_msg->id.idiag_src,
                       src_buf, text_size))
-               return false;
+               return -1;
 
        if (diag_msg->id.idiag_dport ||
            memcmp(zero_addr, diag_msg->id.idiag_dst, addr_size)) {
@@ -125,7 +125,7 @@ inet_parse_response(const char *proto_name, const void *data, int data_len,
 
                if (!inet_ntop(diag_msg->idiag_family, diag_msg->id.idiag_dst,
                               dst_buf, text_size))
-                       return false;
+                       return -1;
 
                tprintf("%s:[%s:%u->%s:%u]",
                        proto_name,
@@ -136,13 +136,14 @@ inet_parse_response(const char *proto_name, const void *data, int data_len,
                        ntohs(diag_msg->id.idiag_sport));
        }
 
-       return true;
+       return 1;
 }
 
 static bool
 receive_responses(const int fd, const unsigned long inode,
                  const char *proto_name,
-                 bool (* parser) (const char *, const void *, int, const unsigned long))
+                 int (* parser) (const char *, const void *,
+                                 int, unsigned long))
 {
        static long buf[8192 / sizeof(long)];
        struct sockaddr_nl nladdr = {
@@ -156,9 +157,8 @@ receive_responses(const int fd, const unsigned long inode,
 
        for (;;) {
                ssize_t ret;
-               struct nlmsghdr *h;
                struct msghdr msg = {
-                       .msg_name = (void*)&nladdr,
+                       .msg_name = (void *) &nladdr,
                        .msg_namelen = sizeof(nladdr),
                        .msg_iov = &iov,
                        .msg_iovlen = 1
@@ -170,18 +170,19 @@ receive_responses(const int fd, const unsigned long inode,
                                continue;
                        return false;
                }
-               if (!ret)
+
+               struct nlmsghdr *h = (struct nlmsghdr *) buf;
+               if (!NLMSG_OK(h, ret))
                        return false;
-               for (h = (struct nlmsghdr*)buf;
-                    NLMSG_OK(h, ret);
-                    h = NLMSG_NEXT(h, ret)) {
-                       switch (h->nlmsg_type) {
-                               case NLMSG_DONE:
-                               case NLMSG_ERROR:
-                                       return false;
-                       }
-                       if (parser(proto_name, NLMSG_DATA(h), h->nlmsg_len, inode))
+               for (; NLMSG_OK(h, ret); h = NLMSG_NEXT(h, ret)) {
+                       if (h->nlmsg_type != SOCK_DIAG_BY_FAMILY)
+                               return false;
+                       int rc = parser(proto_name, NLMSG_DATA(h),
+                                       h->nlmsg_len, inode);
+                       if (rc > 0)
                                return true;
+                       if (rc < 0)
+                               return false;
                }
                flags = MSG_DONTWAIT;
        }
@@ -222,7 +223,7 @@ unix_send_query(const int fd, const unsigned long inode)
                .iov_len = sizeof(req)
        };
        struct msghdr msg = {
-               .msg_name = (void*)&nladdr,
+               .msg_name = (void *) &nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = &iov,
                .msg_iovlen = 1
@@ -238,9 +239,9 @@ unix_send_query(const int fd, const unsigned long inode)
        }
 }
 
-static bool
-unix_parse_response(const char *proto_name, const void *data, int data_len,
-                   const unsigned long inode)
+static int
+unix_parse_response(const char *proto_name, const void *data,
+                   const int data_len, const unsigned long inode)
 {
        const struct unix_diag_msg *diag_msg = data;
        struct rtattr *attr;
@@ -250,11 +251,11 @@ unix_parse_response(const char *proto_name, const void *data, int data_len,
        char path[UNIX_PATH_MAX + 1];
 
        if (rta_len < 0)
-               return false;
+               return -1;
        if (diag_msg->udiag_ino != inode)
-               return false;
+               return 0;
        if (diag_msg->udiag_family != AF_UNIX)
-               return false;
+               return -1;
 
        for (attr = (struct rtattr *) (diag_msg + 1);
             RTA_OK(attr, rta_len);
@@ -271,7 +272,7 @@ unix_parse_response(const char *proto_name, const void *data, int data_len,
                        break;
                case UNIX_DIAG_PEER:
                        if (RTA_PAYLOAD(attr) >= 4)
-                               peer = *(uint32_t *)RTA_DATA(attr);
+                               peer = *(uint32_t *) RTA_DATA(attr);
                        break;
                }
        }
@@ -296,10 +297,10 @@ unix_parse_response(const char *proto_name, const void *data, int data_len,
                        }
                }
                tprints("]");
-               return true;
+               return 1;
        }
        else
-               return false;
+               return -1;
 }
 
 static bool

diff --git a/tests/netlink_inet_diag.c b/tests/netlink_inet_diag.c
index 8dd50dba0cf741b135adbf35f9dce6e217e8ad93..3754d1bdc2296646eb1a745bd7d15337c90e0b35 100644 (file)
--- a/tests/netlink_inet_diag.c
+++ b/tests/netlink_inet_diag.c
@@ -1,4 +1,6 @@
 /*
+ * This file is part of inet-yy strace test.
+ *
  * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
  * All rights reserved.
  *
@@ -27,6 +29,7 @@
 
 #include "tests.h"
 #include <assert.h>
+#include <errno.h>
 #include <string.h>
 #include <unistd.h>
 #include <netinet/in.h>
@@ -60,7 +63,7 @@ send_query(const int fd, const int family, const int proto)
                .iov_len = sizeof(req)
        };
        struct msghdr msg = {
-               .msg_name = (void*)&nladdr,
+               .msg_name = (void *) &nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = &iov,
                .msg_iovlen = 1
@@ -82,7 +85,7 @@ check_responses(const int fd)
                .iov_len = sizeof(buf)
        };
        struct msghdr msg = {
-               .msg_name = (void*)&nladdr,
+               .msg_name = (void *) &nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = &iov,
                .msg_iovlen = 1
@@ -92,13 +95,23 @@ check_responses(const int fd)
        if (ret <= 0)
                perror_msg_and_skip("recvmsg");
 
-       struct nlmsghdr *h = (struct nlmsghdr*)buf;
+       struct nlmsghdr *h = (struct nlmsghdr *) buf;
        if (!NLMSG_OK(h, ret))
                error_msg_and_skip("!NLMSG_OK");
-       if (h->nlmsg_type == NLMSG_ERROR)
-               error_msg_and_skip("NLMSG_ERROR");
-       if (h->nlmsg_type == NLMSG_DONE)
-               error_msg_and_skip("NLMSG_DONE");
+       if (h->nlmsg_type == NLMSG_ERROR) {
+               const struct nlmsgerr *err = NLMSG_DATA(h);
+               if (h->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
+                       error_msg_and_skip("NLMSG_ERROR");
+               errno = -err->error;
+               perror_msg_and_skip("NLMSG_ERROR");
+       }
+       if (h->nlmsg_type != SOCK_DIAG_BY_FAMILY)
+               error_msg_and_skip("unexpected nlmsg_type %u",
+                                  (unsigned) h->nlmsg_type);
+
+       const struct inet_diag_msg *diag = NLMSG_DATA(h);
+       if (h->nlmsg_len < NLMSG_LENGTH(sizeof(*diag)))
+               error_msg_and_skip("short response");
 }
 
 int main(void)

diff --git a/tests/netlink_unix_diag.c b/tests/netlink_unix_diag.c
index 6e3b63b2e57c8202fa2c18ecddfdf87b9bdec9ca..12033e0fc7f07a91ce05008d8bb9ffd0854becab 100644 (file)
--- a/tests/netlink_unix_diag.c
+++ b/tests/netlink_unix_diag.c
@@ -1,4 +1,6 @@
 /*
+ * This file is part of net-yy-unix strace test.
+ *
  * Copyright (c) 2014-2016 Dmitry V. Levin <ldv@altlinux.org>
  * All rights reserved.
  *
@@ -27,6 +29,7 @@
 
 #include "tests.h"
 #include <assert.h>
+#include <errno.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ -68,7 +71,7 @@ send_query(const int fd, const int family, const int proto)
                .iov_len = sizeof(req)
        };
        struct msghdr msg = {
-               .msg_name = (void*)&nladdr,
+               .msg_name = (void *) &nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = &iov,
                .msg_iovlen = 1
@@ -90,7 +93,7 @@ check_responses(const int fd)
                .iov_len = sizeof(buf)
        };
        struct msghdr msg = {
-               .msg_name = (void*)&nladdr,
+               .msg_name = (void *) &nladdr,
                .msg_namelen = sizeof(nladdr),
                .msg_iov = &iov,
                .msg_iovlen = 1
@@ -100,13 +103,23 @@ check_responses(const int fd)
        if (ret <= 0)
                perror_msg_and_skip("recvmsg");
 
-       struct nlmsghdr *h = (struct nlmsghdr*)buf;
+       struct nlmsghdr *h = (struct nlmsghdr *) buf;
        if (!NLMSG_OK(h, ret))
                error_msg_and_skip("!NLMSG_OK");
-       if (h->nlmsg_type == NLMSG_ERROR)
-               error_msg_and_skip("NLMSG_ERROR");
-       if (h->nlmsg_type == NLMSG_DONE)
-               error_msg_and_skip("NLMSG_DONE");
+       if (h->nlmsg_type == NLMSG_ERROR) {
+               const struct nlmsgerr *err = NLMSG_DATA(h);
+               if (h->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
+                       error_msg_and_skip("NLMSG_ERROR");
+               errno = -err->error;
+               perror_msg_and_skip("NLMSG_ERROR");
+       }
+       if (h->nlmsg_type != SOCK_DIAG_BY_FAMILY)
+               error_msg_and_skip("unexpected nlmsg_type %u",
+                                  (unsigned) h->nlmsg_type);
+
+       const struct unix_diag_msg *diag = NLMSG_DATA(h);
+       if (h->nlmsg_len < NLMSG_LENGTH(sizeof(*diag)))
+               error_msg_and_skip("short response");
 }
 
 #define SUN_PATH "netlink_unix_diag_socket"