[tor-commits] [tor/master] Fix non-triggerable heap corruption at do_getpass().

[nickm at torproject.org]

commit e59f0d4cb964387c5c653d3943ae4ecb9cab55b9
Author: George Kadianakis <desnacked at riseup.net>
Date:   Mon Oct 10 12:03:39 2016 -0400

    Fix non-triggerable heap corruption at do_getpass().
---
 changes/bug19223    | 4 ++++
 src/or/routerkeys.c | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/changes/bug19223 b/changes/bug19223
new file mode 100644
index 0000000..e8ca6d4
--- /dev/null
+++ b/changes/bug19223
@@ -0,0 +1,4 @@
+  o Minor bugfixes (getpass):
+    - Defensively fix a non-triggerable heap corruption at do_getpass() tow
+      protect ourselves from mistakes in the future. Fixes bug #19223; bugfix
+      on 0.2.7.3-rc. Bug found by Guido Vranken, patch by nherring.
\ No newline at end of file
diff --git a/src/or/routerkeys.c b/src/or/routerkeys.c
index 060ffd8..d5e7051 100644
--- a/src/or/routerkeys.c
+++ b/src/or/routerkeys.c
@@ -48,8 +48,8 @@ do_getpass(const char *prompt, char *buf, size_t buflen,
     size_t p2len = strlen(prompt) + 1;
     if (p2len < sizeof(msg))
       p2len = sizeof(msg);
-    prompt2 = tor_malloc(strlen(prompt)+1);
-    memset(prompt2, ' ', p2len);
+    prompt2 = tor_malloc(p2len);
+    memset(prompt2, ' ', p2len - sizeof(msg));
     memcpy(prompt2 + p2len - sizeof(msg), msg, sizeof(msg));
 
     buf2 = tor_malloc_zero(buflen);