[xen stable-4.16] subdom: Fix -Werror=address failure in tmp_emulator

[patchbot@xxxxxxx]

commit 61678abb39f6c79a4fb003d6e279fd501b627c19
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Thu Aug 3 20:52:08 2023 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Aug 8 12:33:49 2023 +0100

    subdom: Fix -Werror=address failure in tmp_emulator
    
    The opensuse-tumbleweed build jobs currently fail with:
    
      /builds/xen-project/xen/stubdom/tpm_emulator-x86_64/crypto/rsa.c: In 
function 'rsa_private':
      /builds/xen-project/xen/stubdom/tpm_emulator-x86_64/crypto/rsa.c:56:7: 
error: the comparison will always evaluate as 'true' for the address of 'p' 
will never be NULL [-Werror=address]
         56 |   if (!key->p || !key->q || !key->u) {
            |       ^
      In file included from 
/builds/xen-project/xen/stubdom/tpm_emulator-x86_64/crypto/rsa.c:17:
      /builds/xen-project/xen/stubdom/tpm_emulator-x86_64/crypto/rsa.h:28:12: 
note: 'p' declared here
         28 |   tpm_bn_t p;
            |            ^
    
    This is because all tpm_bn_t's are 1-element arrays (of either a GMP or
    OpenSSL BIGNUM flavour).
    
    Adjust it to compile.  No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jason Andryuk <jandryuk@xxxxxxxxx>
    (cherry picked from commit 46c5ef609b09cf51d7535aebbc05816eafca4c8d)
---
 stubdom/Makefile                 |  1 +
 stubdom/vtpm-tpm_bn_t-addr.patch | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/stubdom/Makefile b/stubdom/Makefile
index ccfcf5b75f..65fc9903bb 100644
--- a/stubdom/Makefile
+++ b/stubdom/Makefile
@@ -241,6 +241,7 @@ tpm_emulator-$(XEN_TARGET_ARCH): 
tpm_emulator-$(TPMEMU_VERSION).tar.gz
        patch -d $@ -p1 < vtpm_extern.patch
        patch -d $@ -p1 < vtpm-microsecond-duration.patch
        patch -d $@ -p1 < vtpm-command-duration.patch
+       patch -d $@ -p1 < vtpm-tpm_bn_t-addr.patch
        mkdir $@/build
        cd $@/build; CC=${CC} $(CMAKE) .. -DCMAKE_C_FLAGS:STRING="-std=c99 
-DTPM_NO_EXTERN $(TARGET_CPPFLAGS) $(TARGET_CFLAGS) 
-Wno-declaration-after-statement"
        touch $@
diff --git a/stubdom/vtpm-tpm_bn_t-addr.patch b/stubdom/vtpm-tpm_bn_t-addr.patch
new file mode 100644
index 0000000000..53172ae1c2
--- /dev/null
+++ b/stubdom/vtpm-tpm_bn_t-addr.patch
@@ -0,0 +1,18 @@
+All tpm_bn_t's are a 1-element array of one form or another, meaning the code
+below is tautological and triggers -Werror=address.
+
+diff -ru tpm_emulator-x86_64.orig/crypto/rsa.c tpm_emulator-x86_64/crypto/rsa.c
+--- tpm_emulator-x86_64.orig/crypto/rsa.c      2011-12-20 18:30:06.000000000 
+0000
++++ tpm_emulator-x86_64/crypto/rsa.c   2023-08-03 20:44:17.379166284 +0100
+@@ -53,10 +53,7 @@
+   tpm_bn_init2(c, key->size);
+   tpm_bn_import(p, in_len, 1, in);
+ 
+-  if (!key->p || !key->q || !key->u) {
+-    /* c = p ^ d mod n */
+-    tpm_bn_powm(c, p, key->d, key->n);
+-  } else {
++  {
+     tpm_bn_init2(m1, key->size / 2);
+     tpm_bn_init2(m2, key->size / 2);
+     tpm_bn_init2(h, key->size);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16