tpm2: print clear log message in case of dictionary lockout mode (#37894)

Fixes: #32260

src/cryptsetup/cryptsetup-tokens/luks2-tpm2.c

@@ -111,6 +111,10 @@ int acquire_luks2_key(
                         ret_decrypted_key);
         if (r == -EREMOTE)
                 return log_error_errno(r, "TPM key integrity check failed. Key enrolled in superblock most likely does not belong to this TPM.");
+        if (r == -EILSEQ)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOANO), "Bad PIN."); /* cryptsetup docs say we should return ENOANO on bad PIN */
+        if (r == -ENOLCK)
+                return log_error_errno(r, "TPM is in dictionary attack lock-out mode.");
         if (ERRNO_IS_NEG_TPM2_UNSEAL_BAD_PCR(r))
                 return log_error_errno(r, "TPM policy does not match current system state. Either system has been tempered with or policy out-of-date: %m");
         if (r < 0)

src/shared/cryptsetup-tpm2.c

@@ -227,14 +227,14 @@ int acquire_tpm2_key(
                         return log_error_errno(r, "TPM key integrity check failed. Key enrolled in superblock most likely does not belong to this TPM.");
                 if (ERRNO_IS_NEG_TPM2_UNSEAL_BAD_PCR(r))
                         return log_error_errno(r, "TPM policy does not match current system state. Either system has been tempered with or policy out-of-date: %m");
-                if (r < 0) {
-                        log_error_errno(r, "Failed to unseal secret using TPM2: %m");
-
-                        /* We get this error in case there is an authentication policy mismatch. This should
-                         * not happen, but this avoids confusing behavior, just in case. */
-                        if (r != -ENOLCK)
-                                continue;
+                if (r == -ENOLCK)
+                        return log_error_errno(r, "TPM is in dictionary attack lock-out mode.");
+                if (r == -EILSEQ) {
+                        log_warning_errno(r, "Bad PIN.");
+                        continue;
                 }
+                if (r < 0)
+                        return log_error_errno(r, "Failed to unseal secret using TPM2: %m");
 
                 return r;
         }

src/shared/tpm2-util.c

@@ -3134,6 +3134,12 @@ int tpm2_make_policy_session(
                         &SESSION_TEMPLATE_SYM_AES_128_CFB,
                         TPM2_ALG_SHA256,
                         &session->esys_handle);
+        if ((rc & ~TPM2_RC_N_MASK) == TPM2_RC_AUTH_FAIL)
+                return log_debug_errno(SYNTHETIC_ERRNO(EILSEQ),
+                                       "Authorization failure from TPM: %s", sym_Tss2_RC_Decode(rc));
+        if (rc == TPM2_RC_LOCKOUT)
+                return log_debug_errno(SYNTHETIC_ERRNO(ENOLCK),
+                                       "TPM2 device is in dictionary attack lockout mode.");
         if (rc != TSS2_RC_SUCCESS)
                 return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
                                        "Failed to open session in TPM: %s", sym_Tss2_RC_Decode(rc));
@@ -5518,6 +5524,7 @@ int tpm2_unseal(Tpm2Context *c,
          *   -EUCLEAN         → PCR state doesn't match expectations
          *   -EPERM           → stored policy does not match TPM state
          *   -ENOTRECOVERABLE → all other kinds of TPM errors
+         *   -EILSEQ          → bad PIN
          *
          * Of these all four of EREMCHG, ENOANO, EUCLEAN, EPERM can all mean that PCR state is not matching
          * expectations. */
@@ -5657,7 +5664,7 @@ int tpm2_unseal(Tpm2Context *c,
                                         encryption_session,
                                         &policy_session);
                         if (r < 0)
-                                return r;
+                                return r; /* Will return EILSEQ on auth failure (i.e. bad PIN) */
 
                         /* If both public PCR key and pcrlock policies are requested, then generate the
                          * public PCR policy for the first shared, and the pcrlock policy for the 2nd */