From 6a6d40d8e2f2b4cd09e025597a1dfe59685f0ec7 Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Mon, 20 Feb 2023 14:41:10 -0500 Subject: [PATCH] tpm2: Check size of buffer before accessing it (CVE-2023-1017 & -1018) Check that there are sufficient bytes in the buffer before reading the cipherSize from it. Also, reduce the bufferSize variable by the number of bytes that make up the cipherSize to avoid reading and writing bytes beyond the buffer in subsequent steps that do in-place decryption. This fixes CVE-2023-1017 & CVE-2023-1018. Signed-off-by: Stefan Berger --- src/tpm2/CryptUtil.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/tpm2/CryptUtil.c b/src/tpm2/CryptUtil.c index 002fde09..8fae5b69 100644 --- a/src/tpm2/CryptUtil.c +++ b/src/tpm2/CryptUtil.c @@ -830,6 +830,10 @@ CryptParameterDecryption( + sizeof(session->sessionKey.t.buffer))); TPM2B_HMAC_KEY key; // decryption key UINT32 cipherSize = 0; // size of cipher text + + if (leadingSizeInByte > bufferSize) + return TPM_RC_INSUFFICIENT; + // Retrieve encrypted data size. if(leadingSizeInByte == 2) { @@ -837,6 +841,7 @@ CryptParameterDecryption( // data to be decrypted cipherSize = (UINT32)BYTE_ARRAY_TO_UINT16(buffer); buffer = &buffer[2]; // advance the buffer + bufferSize -= 2; } #ifdef TPM4B else if(leadingSizeInByte == 4) @@ -844,6 +849,7 @@ CryptParameterDecryption( // the leading size is four bytes so get the four byte size field cipherSize = BYTE_ARRAY_TO_UINT32(buffer); buffer = &buffer[4]; //advance pointer + bufferSize -= 4; } #endif else