[tor-commits] [tor/master] Ensure that bw_file_headers is not bigger than max

[nickm at torproject.org]

commit 8164534f4669b2a3de075d1f57176540406be991
Author: juga0 <juga at riseup.net>
Date:   Sat Jun 30 13:56:38 2018 +0000

    Ensure that bw_file_headers is not bigger than max
---
 src/feature/dirauth/dirvote.c  | 23 ++++++++++++++++-------
 src/feature/dirauth/dirvote.h  |  3 +++
 src/feature/dircache/dirserv.c |  8 +++++---
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/feature/dirauth/dirvote.c b/src/feature/dirauth/dirvote.c
index b123f73a4..e3b701607 100644
--- a/src/feature/dirauth/dirvote.c
+++ b/src/feature/dirauth/dirvote.c
@@ -254,7 +254,7 @@ format_networkstatus_vote(crypto_pk_t *private_signing_key,
     /* XXXX Abstraction violation: should be pulling a field out of v3_ns.*/
     char *flag_thresholds = dirserv_get_flag_thresholds_line();
     char *params;
-    char *bw_file_headers;
+    char *bw_file_headers = NULL;
     authority_cert_t *cert = v3_ns->cert;
     char *methods =
       make_consensus_method_list(MIN_SUPPORTED_CONSENSUS_METHOD,
@@ -269,11 +269,19 @@ format_networkstatus_vote(crypto_pk_t *private_signing_key,
     else
       params = tor_strdup("");
     tor_assert(cert);
-    if (v3_ns->bw_file_headers)
-      bw_file_headers = smartlist_join_strings(v3_ns->bw_file_headers, " ", 0,
-                                              NULL);
-    else
-      bw_file_headers = tor_strdup("");
+
+    if (v3_ns->bw_file_headers) {
+      if (! BUG(smartlist_len(v3_ns->bw_file_headers)
+                > MAX_BW_FILE_HEADER_COUNT_IN_VOTE)) {
+        bw_file_headers = smartlist_join_strings(v3_ns->bw_file_headers, " ",
+                                                 0, NULL);
+        if (BUG(strlen(bw_file_headers) > MAX_BW_FILE_HEADERS_LINE_LEN)) {
+          /* Free and set to NULL, so the vote header line is empty */
+          tor_free(bw_file_headers);
+        }
+      }
+    }
+
     smartlist_add_asprintf(chunks,
                  "network-status-version 3\n"
                  "vote-status %s\n"
@@ -309,7 +317,8 @@ format_networkstatus_vote(crypto_pk_t *private_signing_key,
                  voter->contact,
                  shared_random_vote_str ?
                            shared_random_vote_str : "",
-                 bw_file_headers);
+                 bw_file_headers ?
+                           bw_file_headers : "");
 
     tor_free(params);
     tor_free(flags);
diff --git a/src/feature/dirauth/dirvote.h b/src/feature/dirauth/dirvote.h
index 7ce8e4a69..979a2be8a 100644
--- a/src/feature/dirauth/dirvote.h
+++ b/src/feature/dirauth/dirvote.h
@@ -89,6 +89,9 @@
 #define DGV_INCLUDE_PENDING 2
 #define DGV_INCLUDE_PREVIOUS 4
 
+/** Maximum size of a line in a vote. */
+#define MAX_BW_FILE_HEADERS_LINE_LEN 1024
+
 /*
  * Public API. Used outside of the dirauth subsystem.
  *
diff --git a/src/feature/dircache/dirserv.c b/src/feature/dircache/dirserv.c
index c3ccc3c8f..411a1a0bd 100644
--- a/src/feature/dircache/dirserv.c
+++ b/src/feature/dircache/dirserv.c
@@ -2679,17 +2679,19 @@ dirserv_read_measured_bandwidths(const char *from_file,
           applied_lines++;
       /* if the terminator is found, it is the end of header lines, set the
        * flag but do not store anything */
-      } else if (strcmp(line, BW_FILE_TERMINATOR) == 0)
+      } else if (strcmp(line, BW_FILE_HEADERS_TERMINATOR) == 0) {
         line_is_after_headers = 1;
       /* if the line was not a correct relay line nor the terminator and
        * the end of the header lines has not been detected yet
        * and it is key_value and bw_file_headers did not reach the maximum
        * number of headers,
        * then assume this line is a header and add it to bw_file_headers */
-      else if (bw_file_headers &&
+      } else if (bw_file_headers &&
               (line_is_after_headers == 0) &&
               string_is_key_value(LOG_DEBUG, line) &&
-              (smartlist_len(bw_file_headers) < MAX_BW_FILE_HEADERS_LEN)) {
+              !strchr(line, ' ') &&
+              (smartlist_len(bw_file_headers)
+               < MAX_BW_FILE_HEADER_COUNT_IN_VOTE)) {
         line[strlen(line)-1] = '\0';
         smartlist_add_strdup(bw_file_headers, line);
       };