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tpm2: do not call Esys_TR_Close()

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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.
This commit is contained in:
Dan Streetman 2023-10-09 12:27:10 -04:00
parent adcd3266ec
commit 1524184dd1
1 changed files with 16 additions and 6 deletions
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22
src/shared/tpm2-util.c
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@ -699,12 +699,22 @@ 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));
}