[tor-commits] [tor/master] Max HS descriptor size is now 50kb and also consensus param.

[nickm at torproject.org]

commit e1d7661412325bb8c81a3a7f4d5cc25efdee5a78
Author: George Kadianakis <desnacked at riseup.net>
Date:   Fri Dec 23 14:48:05 2016 +0200

    Max HS descriptor size is now 50kb and also consensus param.
---
 src/or/hs_cache.c      | 13 +++++++++++++
 src/or/hs_cache.h      |  2 ++
 src/or/hs_descriptor.c |  4 +++-
 src/or/hs_descriptor.h |  2 +-
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/or/hs_cache.c b/src/or/hs_cache.c
index b7ff979..6e23a74 100644
--- a/src/or/hs_cache.c
+++ b/src/or/hs_cache.c
@@ -15,6 +15,7 @@
 #include "config.h"
 #include "hs_common.h"
 #include "hs_descriptor.h"
+#include "networkstatus.h"
 #include "rendcache.h"
 
 /* Directory descriptor cache. Map indexed by blinded key. */
@@ -366,6 +367,18 @@ hs_cache_handle_oom(time_t now, size_t min_remove_bytes)
   return bytes_removed;
 }
 
+/**
+ * Return the maximum size of an HS descriptor we are willing to accept as an
+ * HSDir.
+ */
+unsigned int
+hs_cache_get_max_descriptor_size(void)
+{
+  return (unsigned) networkstatus_get_param(NULL,
+                                            "HSV3MaxDescriptorSize",
+                                            HS_DESC_MAX_LEN, 1, INT32_MAX);
+}
+
 /* Initialize the hidden service cache subsystem. */
 void
 hs_cache_init(void)
diff --git a/src/or/hs_cache.h b/src/or/hs_cache.h
index 01abb80..ba95e73 100644
--- a/src/or/hs_cache.h
+++ b/src/or/hs_cache.h
@@ -44,6 +44,8 @@ void hs_cache_free_all(void);
 void hs_cache_clean_as_dir(time_t now);
 size_t hs_cache_handle_oom(time_t now, size_t min_remove_bytes);
 
+unsigned int hs_cache_get_max_descriptor_size(void);
+
 /* Store and Lookup function. They are version agnostic that is depending on
  * the requested version of the descriptor, it will be re-routed to the
  * right function. */
diff --git a/src/or/hs_descriptor.c b/src/or/hs_descriptor.c
index 75ad205..2e92c89 100644
--- a/src/or/hs_descriptor.c
+++ b/src/or/hs_descriptor.c
@@ -15,6 +15,7 @@
 #include "ed25519_cert.h" /* Trunnel interface. */
 #include "parsecommon.h"
 #include "rendcache.h"
+#include "hs_cache.h"
 #include "torcert.h" /* tor_cert_encode_ed22519() */
 
 /* Constant string value used for the descriptor format. */
@@ -1700,8 +1701,9 @@ hs_desc_decode_plaintext(const char *encoded,
   tor_assert(encoded);
   tor_assert(plaintext);
 
+  /* Check that descriptor is within size limits. */
   encoded_len = strlen(encoded);
-  if (encoded_len >= HS_DESC_MAX_LEN) {
+  if (encoded_len >= hs_cache_get_max_descriptor_size()) {
     log_warn(LD_REND, "Service descriptor is too big (%lu bytes)",
              (unsigned long) encoded_len);
     goto err;
diff --git a/src/or/hs_descriptor.h b/src/or/hs_descriptor.h
index 083d353..e0abcea 100644
--- a/src/or/hs_descriptor.h
+++ b/src/or/hs_descriptor.h
@@ -54,7 +54,7 @@
   HS_DESC_ENCRYPTED_SALT_LEN + \
   HS_DESC_PLAINTEXT_PADDING_MULTIPLE + DIGEST256_LEN
 /* Maximum length in bytes of a full hidden service descriptor. */
-#define HS_DESC_MAX_LEN 32768 // XXX justify
+#define HS_DESC_MAX_LEN 50000 /* 50kb max size */
 /* The minimum amount of fields a descriptor should contain. The parsing of
  * the fields are version specific so the only required field, as a generic
  * view of a descriptor, is 1 that is the version field. */