auth-filters: do not use HMAC-SHA1

Though SHA1 is broken, HMAC-SHA1 is still fine. But let's not push our
luck; SHA256 is more sensible anyway.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

2 files changed, 4 insertions, 4 deletions

diff --git a/filters/gentoo-ldap-authentication.lua b/filters/gentoo-ldap-authentication.lua
index 6d8eb3e..c1e382f 100644
--- a/filters/gentoo-ldap-authentication.lua
+++ b/filters/gentoo-ldap-authentication.lua
@@ -271,7 +271,7 @@ function validate_value(expected_field, cookie)
         end
 
         -- Lua hashes strings, so these comparisons are time invariant.
-        if hmac ~= crypto.hmac.digest("sha1", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
+        if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
                 return nil
         end
 
@@ -296,7 +296,7 @@ function secure_value(field, value, expiration)
         value = url_encode(value)
         field = url_encode(field)
         authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
-        authstr = authstr .. "|" .. crypto.hmac.digest("sha1", authstr, secret)
+        authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, secret)
         return authstr
 end
 
diff --git a/filters/simple-authentication.lua b/filters/simple-authentication.lua
index de34d09..596c041 100644
--- a/filters/simple-authentication.lua
+++ b/filters/simple-authentication.lua
@@ -231,7 +231,7 @@ function validate_value(expected_field, cookie)
         end
 
         -- Lua hashes strings, so these comparisons are time invariant.
-        if hmac ~= crypto.hmac.digest("sha1", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
+        if hmac ~= crypto.hmac.digest("sha256", field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt, secret) then
                 return nil
         end
 
@@ -256,7 +256,7 @@ function secure_value(field, value, expiration)
         value = url_encode(value)
         field = url_encode(field)
         authstr = field .. "|" .. value .. "|" .. tostring(expiration) .. "|" .. salt
-        authstr = authstr .. "|" .. crypto.hmac.digest("sha1", authstr, secret)
+        authstr = authstr .. "|" .. crypto.hmac.digest("sha256", authstr, secret)
         return authstr
 end