From 6ecf383d8680e1ccb9bf508b34ed9467e6d87574 Mon Sep 17 00:00:00 2001 From: Dan Streetman Date: Mon, 9 Oct 2023 12:27:10 -0400 Subject: [PATCH] tpm2: do not call Esys_TR_Close() Unfortunately, the tpm2-tss library doesn't reference count handles, and a call to Esys_TR_Close() will remove the handle that could be in use by other code. So stop calling Esys_TR_Close(), and leave the handle around until we cleanup the entire ESYS_CONTEXT. (cherry picked from commit 1524184dd1cb9607ce3e4b9f278c9b231f639e38) Related: RHEL-16182 --- src/shared/tpm2-util.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/src/shared/tpm2-util.c b/src/shared/tpm2-util.c index c287809450..c487b1f0ee 100644 --- a/src/shared/tpm2-util.c +++ b/src/shared/tpm2-util.c @@ -692,12 +692,22 @@ static void tpm2_handle_cleanup(ESYS_CONTEXT *esys_context, ESYS_TR esys_handle, if (flush) rc = sym_Esys_FlushContext(esys_context, esys_handle); else - rc = sym_Esys_TR_Close(esys_context, &esys_handle); - if (rc != TSS2_RC_SUCCESS) /* We ignore failures here (besides debug logging), since this is called - * in error paths, where we cannot do anything about failures anymore. And - * when it is called in successful codepaths by this time we already did - * what we wanted to do, and got the results we wanted so there's no - * reason to make this fail more loudly than necessary. */ + /* We can't use Esys_TR_Close() because the tpm2-tss library does not use reference counting + * for handles, and a single Esys_TR_Close() will remove the handle (internal to the tpm2-tss + * library) that might be in use by other code that is using the same ESYS_CONTEXT. This + * directly affects us; for example the src/test/test-tpm2.c test function + * check_seal_unseal() will encounter this issue and will result in a failure when trying to + * cleanup (i.e. Esys_FlushContext) the transient primary key that the test function + * generates. However, not calling Esys_TR_Close() here should be ok, since any leaked handle + * references will be cleaned up when we free our ESYS_CONTEXT. + * + * An upstream bug is open here: https://github.com/tpm2-software/tpm2-tss/issues/2693 */ + rc = TSS2_RC_SUCCESS; // FIXME: restore sym_Esys_TR_Close() use once tpm2-tss is fixed and adopted widely enough + if (rc != TSS2_RC_SUCCESS) + /* We ignore failures here (besides debug logging), since this is called in error paths, + * where we cannot do anything about failures anymore. And when it is called in successful + * codepaths by this time we already did what we wanted to do, and got the results we wanted + * so there's no reason to make this fail more loudly than necessary. */ log_debug("Failed to %s TPM handle, ignoring: %s", flush ? "flush" : "close", sym_Tss2_RC_Decode(rc)); }