Changeset 8df87c4

Timestamp:

12/19/18 15:35:26 (2 years ago)

Author:

Jacob Van Walraven <jcv9@…>

Branches:

develop

Children:

630460b

Parents:

6327ce6

Message:

Instead we should still copy the filter but make sure its freed when copying another, this protects against the user freeing a filter that is in use. Issue #87

Location:

lib

Files:

• format_linux_common.c (modified) (5 diffs)
• format_linux_ring.c (modified) (1 diff)

lib/format_linux_common.c

@@ -66 +66 @@
         unsigned int arphrd;
         libtrace_dlt_t dlt;
+        libtrace_filter_t *f;
         int sock;
         pcap_t *pcap;
+
+        /* Take a copy of the filter structure to prevent against
+         * deletion causing the filter to no longer work */
+        f = (libtrace_filter_t *) malloc(sizeof(libtrace_filter_t));
+        memcpy(f, filter, sizeof(libtrace_filter_t));
+        f->filterstring = strdup(filter->filterstring);
 
         /* If we are passed a filter with "flag" set to zero, then we must
@@ -78 +85 @@
          * anything (we've just copied it above).
          */
-        if (filter->flag == 0) {
+        if (f->flag == 0) {
                 sock = socket(PF_INET, SOCK_STREAM, 0);
                 memset(&ifr, 0, sizeof(struct ifreq));
@@ -94 +101 @@
                                 FORMAT_DATA->snaplen);
 
-                if (pcap_compile(pcap, &filter->filter, filter->filterstring, 0, 0) == -1) {
+                if (pcap_compile(pcap, &f->filter, f->filterstring, 0, 0) == -1) {
                         /* Filter didn't compile, set flag to 0 so we can
                          * detect this when trace_start() is called and
                          * produce a useful error
                          */
-                        filter->flag = 0;
+                        f->flag = 0;
                         trace_set_err(libtrace, TRACE_ERR_INIT_FAILED,
                                       "Failed to compile BPF filter (%s): %s",
-                                      filter->filterstring, pcap_geterr(pcap));
+                                      f->filterstring, pcap_geterr(pcap));
                 } else {
                         /* Set the "flag" to indicate that the filterstring
                          * has been compiled
                          */
-                        filter->flag = 1;
+                        f->flag = 1;
                 }
 
@@ -113 +120 @@
 
         }
+
+        if (FORMAT_DATA->filter != NULL)
+                trace_destroy_filter(FORMAT_DATA->filter);
 
         FORMAT_DATA->filter = filter;
@@ -489 +499 @@
 {
         if (libtrace->format_data) {
+                if (FORMAT_DATA->filter != NULL)
+                        trace_destroy_filter(FORMAT_DATA->filter);
 
                 if (FORMAT_DATA->per_stream)

lib/format_linux_ring.c

@@ -307 +307 @@
                         }
                 }
+
+                if (FORMAT_DATA->filter != NULL)
+                        trace_destroy_filter(FORMAT_DATA->filter);
 
                 if (FORMAT_DATA->per_stream)