From: cypherpunks <cypherpunks@torproject.org>
Date: Fri, 21 Sep 2018 04:57:26 +0000 (+0000)
Subject: rust/protover: fix null deref in protover_all_supported()
X-Git-Tag: tor-0.3.3.11~25^2^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=db89b4b1527103455e1bd85839a88d614a402354;p=thirdparty%2Ftor.git

rust/protover: fix null deref in protover_all_supported()

Fortunately with the current callers it couldn't happen in practice.

Fix on d1820c1516a31a149fc51a9e5126bf899e4c4e08.
---

diff --git a/changes/bug27804 b/changes/bug27804
new file mode 100644
index 0000000000..fa7fec0bc5
--- /dev/null
+++ b/changes/bug27804
@@ -0,0 +1,3 @@
+  o Minor bugfixes (rust):
+    - Fix a potential null dereference in protover_all_supported().
+      Add a test for it. Fixes bug 27804; bugfix on 0.3.3.1-alpha.
diff --git a/src/rust/protover/ffi.rs b/src/rust/protover/ffi.rs
index 9656e8c318..ca9a504fe1 100644
--- a/src/rust/protover/ffi.rs
+++ b/src/rust/protover/ffi.rs
@@ -68,6 +68,9 @@ pub extern "C" fn protover_all_supported(
 
     if maybe_unsupported.is_some() {
         let unsupported: UnvalidatedProtoEntry = maybe_unsupported.unwrap();
+        if missing_out.is_null() {
+            return 0;
+        }
         let c_unsupported: CString = match CString::new(unsupported.to_string()) {
             Ok(n) => n,
             Err(_) => return 1,
diff --git a/src/test/test_protover.c b/src/test/test_protover.c
index fb374c728b..d1fc7752dd 100644
--- a/src/test/test_protover.c
+++ b/src/test/test_protover.c
@@ -259,6 +259,7 @@ test_protover_all_supported(void *arg)
   tt_ptr_op(msg, OP_EQ, NULL);
 
   // Some things we don't support
+  tt_assert(! protover_all_supported("Wombat=9", NULL));
   tt_assert(! protover_all_supported("Wombat=9", &msg));
   tt_str_op(msg, OP_EQ, "Wombat=9");
   tor_free(msg);