[Openvpn-devel] auth_token/tls_crypt: fix usage of md_valid()

Message ID 20220215102609.14671-1-a@unstable.cc
State Superseded
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Series
  • [Openvpn-devel] auth_token/tls_crypt: fix usage of md_valid()
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Commit Message

Antonio Quartulli Feb. 15, 2022, 10:26 a.m.
With b39725cf ("Remove md_kt_t and change crypto API to use const char*")
the logic for validating ciphers and md algorithms has been changed.

We should now *always* use md_valid() when validating a digest alg.

At the same time, add '!' (negation) when validating the digest algorithm
in the tls-crypt code, in order to restore the proper logic.

Cc: Arne Schwabe <arne@rfc2549.org>
Fixes: b39725cf ("Remove md_kt_t and change crypto API to use const char*")
Reported-by: Richard T Bonhomme <tincantech@protonmail.com>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
---
 src/openvpn/auth_token.c | 2 +-
 src/openvpn/tls_crypt.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Comments

Arne Schwabe Feb. 15, 2022, 12:27 p.m. | #1
Am 15.02.22 um 11:26 schrieb Antonio Quartulli:
> With b39725cf ("Remove md_kt_t and change crypto API to use const char*")
> the logic for validating ciphers and md algorithms has been changed.
> 
> We should now *always* use md_valid() when validating a digest alg.
> 
> At the same time, add '!' (negation) when validating the digest algorithm
> in the tls-crypt code, in order to restore the proper logic.
> 
> Cc: Arne Schwabe <arne@rfc2549.org>
> Fixes: b39725cf ("Remove md_kt_t and change crypto API to use const char*")
> Reported-by: Richard T Bonhomme <tincantech@protonmail.com>
> Signed-off-by: Antonio Quartulli <a@unstable.cc>

Acked-By: Arne Schwabe <arne@rfc2549.org>

Patch

diff --git a/src/openvpn/auth_token.c b/src/openvpn/auth_token.c
index ceae68f6..10c9dde6 100644
--- a/src/openvpn/auth_token.c
+++ b/src/openvpn/auth_token.c
@@ -38,7 +38,7 @@  auth_token_kt(void)
     kt.cipher = "none";
     kt.digest = "SHA256";
 
-    if (!kt.digest)
+    if (!md_valid(kt.digest))
     {
         msg(M_WARN, "ERROR: --tls-crypt requires HMAC-SHA-256 support.");
         return (struct key_type) { 0 };
diff --git a/src/openvpn/tls_crypt.c b/src/openvpn/tls_crypt.c
index 610168b0..aae2a917 100644
--- a/src/openvpn/tls_crypt.c
+++ b/src/openvpn/tls_crypt.c
@@ -59,7 +59,7 @@  tls_crypt_kt(void)
         msg(M_WARN, "ERROR: --tls-crypt requires AES-256-CTR support.");
         return (struct key_type) { 0 };
     }
-    if (cipher_valid(kt.digest))
+    if (!md_valid(kt.digest))
     {
         msg(M_WARN, "ERROR: --tls-crypt requires HMAC-SHA-256 support.");
         return (struct key_type) { 0 };