From fdfae3727ce2d862c5b7d98106c987202d190712 Mon Sep 17 00:00:00 2001
From: Simon Glass <sjg@chromium.org>
Date: Thu, 13 May 2021 19:39:29 -0600
Subject: [PATCH] tpm: Check outgoing command size

In tpm_sendrecv_command() the command buffer is passed in. If a mistake is
somehow made in setting this up, the size could be out of range. Add a
sanity check for this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported-by: Coverity (CID: 331152)
---
 lib/tpm-common.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/tpm-common.c b/lib/tpm-common.c
index 4277846fdd..82ffdc5341 100644
--- a/lib/tpm-common.c
+++ b/lib/tpm-common.c
@@ -176,6 +176,11 @@ u32 tpm_sendrecv_command(struct udevice *dev, const void *command,
 	}
 
 	size = tpm_command_size(command);
+
+	/* sanity check, which also helps coverity */
+	if (size > COMMAND_BUFFER_SIZE)
+		return log_msg_ret("size", -E2BIG);
+
 	log_debug("TPM request [size:%d]: ", size);
 	for (i = 0; i < size; i++)
 		log_debug("%02x ", ((u8 *)command)[i]);
-- 
2.39.5