tpm2-pkcs11: fix build failure

Use patch submitted upstream to fix build error:
| src/lib/tpm.c: In function ‘tpm_unseal’:
| src/lib/tpm.c:1040:16: error: incompatible types when returning type ‘_Bool’ but ‘twist’ {aka ‘const char *’} was expected
|  1040 |         return false;
|       |                ^~~~~

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Scott Murray <scott.murray@konsulko.com>

2 files changed, 29 insertions, 0 deletions

diff --git a/meta-tpm/recipes-tpm2/tpm2-pkcs11/files/0001-src-lib-tpm-return-NULL-for-twist-on-auth-failure.patch b/meta-tpm/recipes-tpm2/tpm2-pkcs11/files/0001-src-lib-tpm-return-NULL-for-twist-on-auth-failure.patch
new file mode 100644
index 0000000..2992b11
--- /dev/null
+++ b/meta-tpm/recipes-tpm2/tpm2-pkcs11/files/0001-src-lib-tpm-return-NULL-for-twist-on-auth-failure.patch
@@ -0,0 +1,28 @@
+From 0db779aecaae93633be963ffb8fdb097c85cc166 Mon Sep 17 00:00:00 2001
+From: Peter Marko <peter.marko@siemens.com>
+Date: Thu, 9 Apr 2026 00:00:00 +0000
+Subject: [PATCH] src/lib/tpm: return NULL for twist on auth failure
+
+`tpm_unseal` returns `twist` (a const char pointer alias). Returning
+`false` in the error path is a type mismatch that fails with stricter
+compiler settings. Return `NULL` instead.
+
+Upstream-Status: Submitted [https://github.com/tpm2-software/tpm2-pkcs11/pull/923]
+Signed-off-by: Peter Marko <peter.marko@siemens.com>
+---
+ src/lib/tpm.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/lib/tpm.c b/src/lib/tpm.c
+index 5fff5d5..c51d984 100644
+--- a/src/lib/tpm.c
++++ b/src/lib/tpm.c
+@@ -1037,7 +1037,7 @@ twist tpm_unseal(tpm_ctx *ctx, uint32_t handle, twist objauth) {
+ 
+     bool result = set_esys_auth(ctx->esys_ctx, handle, objauth);
+     if (!result) {
+-        return false;
++        return NULL;
+     }
+ 
+     TPM2B_SENSITIVE_DATA *unsealed_data = NULL;
diff --git a/meta-tpm/recipes-tpm2/tpm2-pkcs11/tpm2-pkcs11_1.9.1.bb b/meta-tpm/recipes-tpm2/tpm2-pkcs11/tpm2-pkcs11_1.9.1.bb
index 331dc4f..762b82f 100644
--- a/meta-tpm/recipes-tpm2/tpm2-pkcs11/tpm2-pkcs11_1.9.1.bb
+++ b/meta-tpm/recipes-tpm2/tpm2-pkcs11/tpm2-pkcs11_1.9.1.bb
@@ -7,6 +7,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=0fc19f620a102768d6dbd1e7166e78ab"
 DEPENDS = "autoconf-archive pkgconfig sqlite3 openssl libtss2-dev tpm2-tools libyaml p11-kit python3-setuptools-native"
 
 SRC_URI = "https://github.com/tpm2-software/${BPN}/releases/download/${PV}/${BPN}-${PV}.tar.gz"
+SRC_URI += "file://0001-src-lib-tpm-return-NULL-for-twist-on-auth-failure.patch"
 
 SRC_URI[sha256sum] = "ce24aa5ec2471545576e892b6f64fd873a424371bbf9be4ca3a0e689ea11c9b7"