Diff options
| -rw-r--r-- | custom/extensions/auth-file.lua | 6 | |
| -rw-r--r-- | custom/extensions/auth-inline.lua | 6 | |
| -rw-r--r-- | tests/extensions/test-auth.lua | 22 |
3 files changed, 32 insertions, 2 deletions
diff --git a/custom/extensions/auth-file.lua b/custom/extensions/auth-file.lua index 90f597b..f43eb82 100644 --- a/custom/extensions/auth-file.lua +++ b/custom/extensions/auth-file.lua @@ -86,6 +86,10 @@ local cookie_path = "/" -- Set this true only if cgit is served over plain HTTP with no TLS anywhere. local cookie_insecure = false +-- crypt feeds the password into most of its rounds, so its work grows with +-- the password's length, and one longer than this is turned down unchecked. +local max_password_bytes = 256 + -- A throwaway hash of the documented shape, used only to spend the same work -- on a missing account as on a present one, so a failed login does not reveal -- by timing whether the user name exists. @@ -449,7 +453,7 @@ function authenticate_post() local username = post["username"] local password = post["password"] local ok = false - if username ~= nil and password ~= nil then + if username ~= nil and password ~= nil and #password <= max_password_bytes then local hash = account_hash(username) if hash == nil then -- Spend the work anyway, see dummy_hash. diff --git a/custom/extensions/auth-inline.lua b/custom/extensions/auth-inline.lua index de91f88..53b1efc 100644 --- a/custom/extensions/auth-inline.lua +++ b/custom/extensions/auth-inline.lua @@ -86,6 +86,10 @@ local cookie_path = "/" -- Set this true only if cgit is served over plain HTTP with no TLS anywhere. local cookie_insecure = false +-- crypt feeds the password into most of its rounds, so its work grows with +-- the password's length, and one longer than this is turned down unchecked. +local max_password_bytes = 256 + -- A throwaway hash of the documented shape, used only to spend the same work -- on a missing account as on a present one, so a failed login does not reveal -- by timing whether the user name exists. @@ -411,7 +415,7 @@ function authenticate_post() local username = post["username"] local password = post["password"] local ok = false - if username ~= nil and password ~= nil then + if username ~= nil and password ~= nil and #password <= max_password_bytes then local hash = account_hash(username) if hash == nil then -- Spend the work anyway, see dummy_hash. diff --git a/tests/extensions/test-auth.lua b/tests/extensions/test-auth.lua index 5d3541c..97638bd 100644 --- a/tests/extensions/test-auth.lua +++ b/tests/extensions/test-auth.lua @@ -278,6 +278,28 @@ out, ret = run_action("authenticate-post", { }) h.contains("an unknown user is told nothing different", out, "Set-Cookie: cgitauth=; ") +-- crypt's work grows with the password, so one past the cap is turned down +-- before crypt sees it. +local unistd = require("posix.unistd") +local real_crypt = unistd.crypt +local crypt_calls = 0 +unistd.crypt = function(...) + crypt_calls = crypt_calls + 1 + return real_crypt(...) +end +out, ret = run_action("authenticate-post", { + method = "POST", + body = "username=Alice&password=" .. string.rep("a", 257) .. "&redirect=" .. url_encode(way_back), +}) +h.contains("an overlong password is turned down", out, "Set-Cookie: cgitauth=; ") +h.equals("without spending crypt on it", crypt_calls, 0) +out, ret = run_action("authenticate-post", { + method = "POST", + body = "username=Alice&password=" .. string.rep("a", 256) .. "&redirect=" .. url_encode(way_back), +}) +h.equals("a password at the cap is still checked", crypt_calls, 1) +unistd.crypt = real_crypt + out, ret = run_action("authenticate-post", { method = "POST", body = "username=Alice&password=" .. url_encode(password), |