tpm2-tools/0004-tpm2_checkquote-Add-comparison-of-pcr-selection.patch
Štěpán Horáček acfe6b50eb Backport upstream fixes
Includes fixes for CVE-2024-29038 and CVE-2024-29039.

Resolves: RHEL-23198
Resolves: RHEL-41031
Resolves: RHEL-41035

Signed-off-by: Štěpán Horáček <shoracek@redhat.com>
2024-06-19 16:20:36 +02:00

87 lines
3.0 KiB
Diff

From 7076608db4b8a2cdcab6ff4bc47c23c935618e3b Mon Sep 17 00:00:00 2001
From: Juergen Repp <juergen_repp@web.de>
Date: Tue, 5 Mar 2024 22:11:38 +0100
Subject: [PATCH 4/6] tpm2_checkquote: Add comparison of pcr selection.
The pcr selection which is passed with the --pcr parameter it not
compared with the attest. So it's possible to fake a valid
attestation.
Fixes: CVE-2024-29039
Signed-off-by: Juergen Repp <juergen_repp@web.de>
Signed-off-by: Andreas Fuchs <andreas.fuchs@infineon.com>
---
tools/misc/tpm2_checkquote.c | 41 +++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)
diff --git a/tools/misc/tpm2_checkquote.c b/tools/misc/tpm2_checkquote.c
index 6ce086f8..8a2a154e 100644
--- a/tools/misc/tpm2_checkquote.c
+++ b/tools/misc/tpm2_checkquote.c
@@ -54,6 +54,37 @@ static tpm2_verifysig_ctx ctx = {
.pcr_hash = TPM2B_TYPE_INIT(TPM2B_DIGEST, buffer),
};
+static bool compare_pcr_selection(TPML_PCR_SELECTION *attest_sel, TPML_PCR_SELECTION *pcr_sel) {
+ if (attest_sel->count != pcr_sel->count) {
+ LOG_ERR("Selection sizes do not match.");
+ return false;
+ }
+ for (uint32_t i = 0; i < attest_sel->count; i++) {
+ for (uint32_t j = 0; j < pcr_sel->count; j++) {
+ if (attest_sel->pcrSelections[i].hash ==
+ pcr_sel->pcrSelections[j].hash) {
+ if (attest_sel->pcrSelections[i].sizeofSelect !=
+ pcr_sel->pcrSelections[j].sizeofSelect) {
+ LOG_ERR("Bitmask size does not match");
+ return false;
+ }
+ if (memcmp(&attest_sel->pcrSelections[i].pcrSelect[0],
+ &pcr_sel->pcrSelections[j].pcrSelect[0],
+ attest_sel->pcrSelections[i].sizeofSelect) != 0) {
+ LOG_ERR("Selection bitmasks do not match");
+ return false;
+ }
+ break;
+ }
+ if (j == pcr_sel->count - 1) {
+ LOG_ERR("Hash selections to not match.");
+ return false;
+ }
+ }
+ }
+ return true;
+}
+
static bool verify(void) {
bool result = false;
@@ -374,7 +405,7 @@ static tool_rc init(void) {
}
TPM2B_ATTEST *msg = NULL;
- TPML_PCR_SELECTION pcr_select;
+ TPML_PCR_SELECTION pcr_select = { 0 };
tpm2_pcrs *pcrs;
tpm2_pcrs temp_pcrs = {};
tool_rc return_value = tool_rc_general_error;
@@ -537,6 +568,14 @@ static tool_rc init(void) {
goto err;
}
+ if (ctx.flags.pcr) {
+ if (!compare_pcr_selection(&ctx.attest.attested.quote.pcrSelect,
+ &pcr_select)) {
+ LOG_ERR("PCR selection does not match PCR slection from attest!");
+ goto err;
+ }
+ }
+
// Figure out the digest for this message
res = tpm2_openssl_hash_compute_data(ctx.halg, msg->attestationData,
msg->size, &ctx.msg_hash);
--
2.45.2