Merge pull request #2696 from sworleys/Netlink-Fuzz

[mirror_frr.git] / zebra / kernel_netlink.c

diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
index cd881dcc244d5cb9fa85eb4819468945a1b1c5a2..c627bda4f7c34f5fb2135c1b71629014f3dcaf67 100644 (file)
--- a/zebra/kernel_netlink.c
+++ b/zebra/kernel_netlink.c
@@ -20,6 +20,11 @@
 
 #include <zebra.h>
 
+#if defined(HANDLE_NETLINK_FUZZING)
+#include <stdio.h>
+#include <string.h>
+#endif /* HANDLE_NETLINK_FUZZING */
+
 #ifdef HAVE_NETLINK
 
 #include "linklist.h"
@@ -293,6 +298,81 @@ static int netlink_information_fetch(struct nlmsghdr *h, ns_id_t ns_id,
        return 0;
 }
 
+#if defined(HANDLE_NETLINK_FUZZING)
+/* Using globals here to avoid adding function parameters */
+
+/* Keep distinct filenames for netlink fuzzy collection */
+static unsigned int netlink_file_counter = 1;
+
+/* File name to read fuzzed netlink from */
+static char netlink_fuzz_file[MAXPATHLEN] = "";
+
+/* Flag for whether to read from file or not */
+bool netlink_read;
+
+/**
+ * netlink_read_init() - Starts the message parser
+ * @fname:      Filename to read.
+ */
+void netlink_read_init(const char *fname)
+{
+       snprintf(netlink_fuzz_file, MAXPATHLEN, "%s", fname);
+       /* Creating this fake socket for testing purposes */
+       struct zebra_ns *zns = zebra_ns_lookup(NS_DEFAULT);
+
+       netlink_parse_info(netlink_information_fetch, &zns->netlink, zns, 1, 0);
+}
+
+/**
+ * netlink_write_incoming() - Writes all data received from netlink to a file
+ * @buf:        Data from netlink.
+ * @size:       Size of data.
+ * @counter:    Counter for keeping filenames distinct.
+ */
+static void netlink_write_incoming(const char *buf, const unsigned int size,
+                                  unsigned int counter)
+{
+       char fname[MAXPATHLEN];
+       FILE *f;
+
+       zserv_privs.change(ZPRIVS_RAISE);
+       snprintf(fname, MAXPATHLEN, "%s/%s_%u", DAEMON_VTY_DIR, "netlink",
+                counter);
+       f = fopen(fname, "w");
+       if (f) {
+               fwrite(buf, 1, size, f);
+               fclose(f);
+       }
+       zserv_privs.change(ZPRIVS_LOWER);
+}
+
+/**
+ * netlink_read_file() - Reads netlink data from file
+ * @buf:        Netlink buffer being overwritten.
+ * @fname:      File name to read from.
+ *
+ * Return:      Size of file.
+ */
+static long netlink_read_file(char *buf, const char *fname)
+{
+       FILE *f;
+       long file_bytes = -1;
+
+       zserv_privs.change(ZPRIVS_RAISE);
+       f = fopen(fname, "r");
+       if (f) {
+               fseek(f, 0, SEEK_END);
+               file_bytes = ftell(f);
+               rewind(f);
+               fread(buf, NL_RCV_PKT_BUF_SIZE, 1, f);
+               fclose(f);
+       }
+       zserv_privs.change(ZPRIVS_LOWER);
+       return file_bytes;
+}
+
+#endif /* HANDLE_NETLINK_FUZZING */
+
 static int kernel_read(struct thread *thread)
 {
        struct zebra_ns *zns = (struct zebra_ns *)THREAD_ARG(thread);
@@ -602,7 +682,18 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
                if (count && read_in >= count)
                        return 0;
 
+#if defined(HANDLE_NETLINK_FUZZING)
+               /* Check if reading and filename is set */
+               if (netlink_read && '\0' != netlink_fuzz_file[0]) {
+                       zlog_debug("Reading netlink fuzz file");
+                       status = netlink_read_file(buf, netlink_fuzz_file);
+                       snl.nl_pid = 0;
+               } else {
+                       status = recvmsg(nl->sock, &msg, 0);
+               }
+#else
                status = recvmsg(nl->sock, &msg, 0);
+#endif /* HANDLE_NETLINK_FUZZING */
                if (status < 0) {
                        if (errno == EINTR)
                                continue;
@@ -636,6 +727,14 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
                        zlog_hexdump(buf, status);
                }
 
+#if defined(HANDLE_NETLINK_FUZZING)
+               if (!netlink_read) {
+                       zlog_debug("Writing incoming netlink message");
+                       netlink_write_incoming(buf, status,
+                                              netlink_file_counter++);
+               }
+#endif /* HANDLE_NETLINK_FUZZING */
+
                read_in++;
                for (h = (struct nlmsghdr *)buf;
                     (status >= 0 && NLMSG_OK(h, (unsigned int)status));