Fix 'uninitialized pointer read' in openvpn_decrypt_aead

Coverity complains that if we error out in the first
error condition we try to free gc without initializing
it.

While here move the declaration of outlen to the first
usage.

Change-Id: I0391f30a1e962ee242e9bcdec4f605bf7e831cca
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Antonio Quartulli <a@unstable.cc>
Message-Id: <20250113112226.17728-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg30421.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
index 84ec436b2337aa06de6f276c269aa7c12c10114e..dbd95a80d67e0f989ccb01bfc49113d2b8db9ccd 100644 (file)
--- a/src/openvpn/crypto.c
+++ b/src/openvpn/crypto.c
@@ -406,17 +406,15 @@ openvpn_decrypt_aead(struct buffer *buf, struct buffer work,
     static const char error_prefix[] = "AEAD Decrypt error";
     struct packet_id_net pin = { 0 };
     struct key_ctx *ctx = &opt->key_ctx_bi.decrypt;
+    struct gc_arena gc;
+
+    gc_init(&gc);
 
     if (cipher_decrypt_verify_fail_exceeded(ctx))
     {
         CRYPT_DROP("Decryption failed verification limit reached.");
     }
 
-    int outlen;
-    struct gc_arena gc;
-
-    gc_init(&gc);
-
     ASSERT(opt);
     ASSERT(frame);
     ASSERT(buf->len > 0);
@@ -506,6 +504,8 @@ openvpn_decrypt_aead(struct buffer *buf, struct buffer work,
     dmsg(D_PACKET_CONTENT, "DECRYPT AD: %s",
          format_hex(ad_start, ad_size, 0, &gc));
 
+    int outlen;
+
     /* Decrypt and authenticate packet */
     if (!cipher_ctx_update(ctx->cipher, BPTR(&work), &outlen, BPTR(buf),
                            data_len))