X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/72fee3fe25c276b1c0bd1dad7b3db8bf0f48dfec..03c037bbd75588beba3ee09f26d17783d21e30bc:/tcpdump.c

diff --git a/tcpdump.c b/tcpdump.c
index 8a3b6ce7..0b654158 100644
--- a/tcpdump.c
+++ b/tcpdump.c
@@ -78,7 +78,9 @@ The Regents of the University of California.  All rights reserved.\n";
 #endif
 /* Capsicum-specific code requires macros from <net/bpf.h>, which will fail
  * to compile if <pcap.h> has already been included; including the headers
- * in the opposite order works fine.
+ * in the opposite order works fine. For the most part anyway, because in
+ * FreeBSD <pcap/pcap.h> declares bpf_dump() instead of <net/bpf.h>. Thus
+ * interface.h takes care of it later to avoid a compiler warning.
  */
 #ifdef HAVE_CAPSICUM
 #include <sys/capsicum.h>
@@ -240,10 +242,6 @@ static int infoprint;
 
 char *program_name;
 
-#ifdef HAVE_CASPER
-cap_channel_t *capdns;
-#endif
-
 /* Forwards */
 static NORETURN void error(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
 static void warning(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
@@ -845,6 +843,8 @@ MakeFilename(char *buffer, char *orig_name, int cnt, int max_chars)
         char *filename = malloc(PATH_MAX + 1);
         if (filename == NULL)
             error("%s: malloc", __func__);
+        if (strlen(orig_name) == 0)
+            error("an empty string is not a valid file name");
 
         /* Process with strftime if Gflag is set. */
         if (Gflag != 0) {
@@ -856,9 +856,25 @@ MakeFilename(char *buffer, char *orig_name, int cnt, int max_chars)
           }
 
           /* There's no good way to detect an error in strftime since a return
-           * value of 0 isn't necessarily failure.
+           * value of 0 isn't necessarily failure; if orig_name is an empty
+           * string, the formatted string will be empty.
+           *
+           * However, the C90 standard says that, if there *is* a
+           * buffer overflow, the content of the buffer is undefined,
+           * so we must check for a buffer overflow.
+           *
+           * So we check above for an empty orig_name, and only call
+           * strftime() if it's non-empty, in which case the return
+           * value will only be 0 if the formatted date doesn't fit
+           * in the buffer.
+           *
+           * (We check above because, even if we don't use -G, we
+           * want a better error message than "tcpdump: : No such
+           * file or directory" for this case.)
            */
-          strftime(filename, PATH_MAX, orig_name, local_tm);
+          if (strftime(filename, PATH_MAX, orig_name, local_tm) == 0) {
+            error("%s: strftime", __func__);
+          }
         } else {
           strncpy(filename, orig_name, PATH_MAX);
         }
@@ -2384,17 +2400,44 @@ DIAG_ON_ASSIGN_ENUM
 #endif
 		if (Cflag != 0 || Gflag != 0) {
 #ifdef HAVE_CAPSICUM
-			dumpinfo.WFileName = strdup(basename(WFileName));
+			/*
+			 * basename() and dirname() may modify their input buffer
+			 * and they do since FreeBSD 12.0, but they didn't before.
+			 * Hence use the return value only, but always assume the
+			 * input buffer has been modified and would need to be
+			 * reset before the next use.
+			 */
+			char *WFileName_copy;
+
+			if ((WFileName_copy = strdup(WFileName)) == NULL) {
+				error("Unable to allocate memory for file %s",
+				    WFileName);
+			}
+			DIAG_OFF_C11_EXTENSIONS
+			dumpinfo.WFileName = strdup(basename(WFileName_copy));
+			DIAG_ON_C11_EXTENSIONS
 			if (dumpinfo.WFileName == NULL) {
 				error("Unable to allocate memory for file %s",
 				    WFileName);
 			}
-			dumpinfo.dirfd = open(dirname(WFileName),
+			free(WFileName_copy);
+
+			if ((WFileName_copy = strdup(WFileName)) == NULL) {
+				error("Unable to allocate memory for file %s",
+				    WFileName);
+			}
+			DIAG_OFF_C11_EXTENSIONS
+			char *WFileName_dirname = dirname(WFileName_copy);
+			DIAG_ON_C11_EXTENSIONS
+			dumpinfo.dirfd = open(WFileName_dirname,
 			    O_DIRECTORY | O_RDONLY);
 			if (dumpinfo.dirfd < 0) {
 				error("unable to open directory %s",
-				    dirname(WFileName));
+				    WFileName_dirname);
 			}
+			free(WFileName_dirname);
+			free(WFileName_copy);
+
 			cap_rights_init(&rights, CAP_CREATE, CAP_FCNTL,
 			    CAP_FTRUNCATE, CAP_LOOKUP, CAP_SEEK, CAP_WRITE);
 			if (cap_rights_limit(dumpinfo.dirfd, &rights) < 0 &&
@@ -2643,7 +2686,7 @@ DIAG_ON_ASSIGN_ENUM
 
 	free(cmdbuf);
 	pcap_freecode(&fcode);
-	exit_tcpdump(status == -1 ? 1 : 0);
+	exit_tcpdump(status == -1 ? S_ERR_HOST_PROGRAM : S_SUCCESS);
 }
 
 /*
@@ -2659,7 +2702,14 @@ static void
 
 	memset(&new, 0, sizeof(new));
 	new.sa_handler = func;
-	if (sig == SIGCHLD)
+	if ((sig == SIGCHLD)
+# ifdef SIGNAL_REQ_INFO
+		|| (sig == SIGNAL_REQ_INFO)
+# endif
+# ifdef SIGNAL_FLUSH_PCAP
+		|| (sig == SIGNAL_FLUSH_PCAP)
+# endif
+		)
 		new.sa_flags = SA_RESTART;
 	if (sigaction(sig, &new, &old) < 0)
 		return (SIG_ERR);