Fix NULL pointer dereference in wolfSSH_SetTpmDev/SetTpmKey

Move the NULL validation checks inside the existing NULL guards for
ssh and ssh->ctx. Previously, the check accessed ssh->ctx outside
the guard, causing a NULL dereference when ssh or ssh->ctx was NULL.
Also fix wolfSSH_SetTpmKey to check tpmKey instead of tpmDev.

Author: LinuxJedi

src/ssh.c

@@ -405,11 +405,12 @@ void wolfSSH_SetTpmDev(WOLFSSH* ssh, WOLFTPM2_DEV* dev)
 {
     WLOG(WS_LOG_DEBUG, "Entering wolfSSH_SetTpmDev()");
 
-    if (ssh && ssh->ctx)
+    if (ssh && ssh->ctx) {
         ssh->ctx->tpmDev = dev;
 
-    if (ssh->ctx->tpmDev == NULL) {
-        WLOG(WS_LOG_DEBUG, "wolfSSH_SetTpmDev: Set tpm dev failed");
+        if (ssh->ctx->tpmDev == NULL) {
+            WLOG(WS_LOG_DEBUG, "wolfSSH_SetTpmDev: Set tpm dev failed");
+        }
     }
 }
 
@@ -418,11 +419,12 @@ void wolfSSH_SetTpmKey(WOLFSSH* ssh, WOLFTPM2_KEY* key)
 {
     WLOG(WS_LOG_DEBUG, "Entering wolfSSH_SetTpmKey()");
 
-    if (ssh && ssh->ctx)
+    if (ssh && ssh->ctx) {
         ssh->ctx->tpmKey = key;
 
-    if (ssh->ctx->tpmDev == NULL) {
-        WLOG(WS_LOG_DEBUG, "wolfSSH_SetTpmKey: Set tpm key failed");
+        if (ssh->ctx->tpmKey == NULL) {
+            WLOG(WS_LOG_DEBUG, "wolfSSH_SetTpmKey: Set tpm key failed");
+        }
     }
 }