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| author | Nick Mathewson <nickm@torproject.org> | 2012-03-31 22:51:28 -0400 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2012-04-01 00:42:04 -0400 |
| commit | 9a69c24150965e54322ed9616638d4f1939b1289 (patch) | |
| tree | a28e0c4d406c63356d95460d77930a6a700c229f /changes | |
| parent | 9740f067c4bed47beb63483be4f4636167a04019 (diff) | |
| download | tor-9a69c24150965e54322ed9616638d4f1939b1289.tar tor-9a69c24150965e54322ed9616638d4f1939b1289.tar.gz | |
Do not use strcmp() to compare an http authenticator to its expected value
This fixes a side-channel attack on the (fortunately unused!)
BridgePassword option for bridge authorities. Fix for bug 5543;
bugfix on 0.2.0.14-alpha.
Diffstat (limited to 'changes')
| -rw-r--r-- | changes/bridgepassword | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/changes/bridgepassword b/changes/bridgepassword new file mode 100644 index 000000000..5f0e250ff --- /dev/null +++ b/changes/bridgepassword @@ -0,0 +1,11 @@ + o Security fixes: + - When using the debuging BridgePassword field, a bridge authority + now compares alleged passwords by hashing them, then comparing + the result to a digest of the expected authenticator. This avoids + a potential side-channel attack in the previous code, which + had foolishly used strcmp(). Fortunately, the BridgePassword field + *is not in use*, but if it had been, the timing + behavior of strcmp() might have allowed an adversary to guess the + BridgePassword value, and enumerate the bridges. Bugfix on + 0.2.0.14-alpha. Fixes bug 5543. + |