tor

commit c8ee12b2e8108658d647aedb92885311291b6f71
parent cabcb752d7ecc2d16e6cb630b3de0684b4f97ec5
Author: Nick Mathewson <nickm@torproject.org>
Date:   Mon, 20 Nov 2017 10:14:41 -0500

Recover better from empty/invalid storagedir files

If we can't read a file because of an FS issue, we say "we can't
read that" and move on.  But if we can't read it because it's empty,
because it has no labels, or because its labels are misformatted, we
should remove it.

Fixes bug 24099; bugfix on 0.3.1.1-alpha.

Diffstat:
A
changes/bug24099
 | 
4
++++
M
src/or/conscache.c
 | 
13
++++++++++---

2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/changes/bug24099 b/changes/bug24099
@@ -0,0 +1,4 @@
+  o Minor bugfixes (directory cache):
+    - Recover better from empty or corrupt files in the consensus cache
+      directory. Fixes bug 24099; bugfix on 0.3.1.1-alpha.
+
diff --git a/src/or/conscache.c b/src/or/conscache.c
@@ -539,9 +539,16 @@ consensus_cache_rescan(consensus_cache_t *cache)
     map = storage_dir_map_labeled(cache->dir, fname,
                                   &labels, &body, &bodylen);
     if (! map) {
-      /* Can't load this; continue */
-      log_warn(LD_FS, "Unable to map file %s from consensus cache: %s",
-               escaped(fname), strerror(errno));
+      if (errno == ERANGE || errno == EINVAL) {
+        log_warn(LD_FS, "Found %s file %s in consensus cache; removing it.",
+                 errno == ERANGE ? "empty" : "misformatted",
+                 escaped(fname));
+        storage_dir_remove_file(cache->dir, fname);
+      } else {
+        /* Can't load this; continue */
+        log_warn(LD_FS, "Unable to map file %s from consensus cache: %s",
+                 escaped(fname), strerror(errno));
+      }
       continue;
     }
     consensus_cache_entry_t *ent =