[PATCH v3 03/10] tpm_emulator: Reject sending commands smaller than the request header

[Stefan Berger <stefanb@linux.ibm.com>]

Reject any TPM request from being sent to the TPM emulator that is shorter
than the size of the request header.

Fixes: f4ede81eed29 ("tpm: Added support for TPM emulator")
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
---
 backends/tpm/tpm_emulator.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/backends/tpm/tpm_emulator.c b/backends/tpm/tpm_emulator.c
index 9c95b4d878..0c9e32f36a 100644
--- a/backends/tpm/tpm_emulator.c
+++ b/backends/tpm/tpm_emulator.c
@@ -181,6 +181,11 @@ static int tpm_emulator_unix_tx_bufs(TPMEmulator *tpm_emu,
     uint32_t to_read;
     ssize_t ret;
 
+    if (in_len < sizeof(struct tpm_req_hdr)) {
+        error_setg(errp, "tpm-emulator: invalid request size %u", in_len);
+        return -1;
+    }
+
     if (selftest_done) {
         *selftest_done = false;
         is_selftest = tpm_util_is_selftest(in, in_len);
-- 
2.55.0