Add fuzzer for legacy I/O log info file.

MANIFEST

@@ -117,6 +117,7 @@ lib/iolog/iolog_json.h
 lib/iolog/iolog_path.c
 lib/iolog/iolog_util.c
 lib/iolog/regress/fuzz/fuzz_iolog_json.c
+lib/iolog/regress/fuzz/fuzz_iolog_legacy.c
 lib/iolog/regress/host_port/host_port_test.c  
 lib/iolog/regress/iolog_json/check_iolog_json.c
 lib/iolog/regress/iolog_json/test1.in

include/sudo_iolog.h

@@ -101,6 +101,7 @@ char *iolog_parse_delay(const char *cp, struct timespec *delay, const char *deci
 int iolog_read_timing_record(struct iolog_file *iol, struct timing_closure *timing);
 struct eventlog *iolog_parse_loginfo(int dfd, const char *iolog_dir);
 bool iolog_parse_loginfo_json(FILE *fp, const char *iolog_dir, struct eventlog *evlog);
+bool iolog_parse_loginfo_legacy(FILE *fp, const char *iolog_dir, struct eventlog *evlog);
 void iolog_adjust_delay(struct timespec *delay, struct timespec *max_delay, double scale_factor);
 
 /* iolog_fileio.c */

lib/iolog/iolog_util.c

@@ -49,7 +49,7 @@
 
 static int timing_event_adj;
 
-static bool
+bool
 iolog_parse_loginfo_legacy(FILE *fp, const char *iolog_dir,
     struct eventlog *evlog)
 {

lib/iolog/regress/fuzz/fuzz_iolog_legacy.c

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2021 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#elif defined(HAVE_INTTYPES_H)
+# include <inttypes.h>
+#endif
+
+#include "sudo_compat.h"
+#include "sudo_debug.h"
+#include "sudo_eventlog.h"
+#include "sudo_iolog.h"
+#include "sudo_util.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+    struct eventlog *evlog = NULL;
+    FILE *fp;
+
+    /* Operate in-memory. */
+    fp = fmemopen((void *)data, size, "r");
+    if (fp == NULL)
+        return 0;
+
+    /* Parsed contents of an I/O log info file are stored in evlog. */
+    evlog = calloc(1, sizeof(*evlog));
+    if (evlog != NULL) {
+	evlog->runuid = (uid_t)-1;
+	evlog->rungid = (gid_t)-1;
+
+	/* Try to parse buffer as a legacy-format I/O log info file. */
+	iolog_parse_loginfo_legacy(fp, "fuzz.legacy", evlog);
+	eventlog_free(evlog);
+    }
+    fclose(fp);
+
+    return 0;
+}