[PATCH 07/12] xen/vmac: Const the key parameter of vmac_set_key()

Andrew Cooper posted 12 patches 1 week, 3 days ago
[PATCH 07/12] xen/vmac: Const the key parameter of vmac_set_key()
Posted by Andrew Cooper 1 week, 3 days ago
Eclair complains that tboot_gen_domain_integrity() is casting away
constness (Rule 11.8 violation).

vmac_set_key() doesn't modify the user_key parameter, so it can become const,
removing the need to cast.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Julien Grall <julien@xen.org>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
CC: Bertrand Marquis <bertrand.marquis@arm.com>
CC: Michal Orzel <michal.orzel@amd.com>
CC: consulting@bugseng.com <consulting@bugseng.com>
CC: Nicola Vetrini <nicola.vetrini@bugseng.com>
---
 xen/arch/x86/tboot.c      | 6 +++---
 xen/crypto/vmac.c         | 2 +-
 xen/include/crypto/vmac.h | 2 +-
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index 0b3d596690cc..5ae27f481f94 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -202,7 +202,7 @@ static void tboot_gen_domain_integrity(const uint8_t key[TB_KEY_SIZE],
     uint8_t nonce[16] = {};
     vmac_ctx_t ctx;
 
-    vmac_set_key((uint8_t *)key, &ctx);
+    vmac_set_key(key, &ctx);
     for_each_domain( d )
     {
         if ( !(d->options & XEN_DOMCTL_CDF_s3_integrity) )
@@ -241,7 +241,7 @@ static void tboot_gen_xenheap_integrity(const uint8_t key[TB_KEY_SIZE],
     uint8_t nonce[16] = {};
     vmac_ctx_t ctx;
 
-    vmac_set_key((uint8_t *)key, &ctx);
+    vmac_set_key(key, &ctx);
     for ( mfn = 0; mfn < max_page; mfn++ )
     {
         struct page_info *page = mfn_to_page(_mfn(mfn));
@@ -272,7 +272,7 @@ static void tboot_gen_frametable_integrity(const uint8_t key[TB_KEY_SIZE],
     uint8_t nonce[16] = {};
     vmac_ctx_t ctx;
 
-    vmac_set_key((uint8_t *)key, &ctx);
+    vmac_set_key(key, &ctx);
     for ( sidx = 0; ; sidx = nidx )
     {
         eidx = find_next_zero_bit(pdx_group_valid, max_idx, sidx);
diff --git a/xen/crypto/vmac.c b/xen/crypto/vmac.c
index f1f6d75f8eeb..c9914d2c7c1d 100644
--- a/xen/crypto/vmac.c
+++ b/xen/crypto/vmac.c
@@ -924,7 +924,7 @@ uint64_t vmac(unsigned char m[],
 
 /* ----------------------------------------------------------------------- */
 
-void vmac_set_key(unsigned char user_key[], vmac_ctx_t *ctx)
+void vmac_set_key(const unsigned char user_key[], vmac_ctx_t *ctx)
 {
     uint64_t in[2] = {0}, out[2];
     unsigned i;
diff --git a/xen/include/crypto/vmac.h b/xen/include/crypto/vmac.h
index 457f3f5dd6da..7574c4a3f328 100644
--- a/xen/include/crypto/vmac.h
+++ b/xen/include/crypto/vmac.h
@@ -161,7 +161,7 @@ uint64_t vhash(unsigned char m[],
  * When passed a VMAC_KEY_LEN bit user_key, this function initialazies ctx.
  * ----------------------------------------------------------------------- */
 
-void vmac_set_key(unsigned char user_key[], vmac_ctx_t *ctx);
+void vmac_set_key(const unsigned char user_key[], vmac_ctx_t *ctx);
 
 /* --------------------------------------------------------------------- */
 
-- 
2.39.5


Re: [PATCH 07/12] xen/vmac: Const the key parameter of vmac_set_key()
Posted by Jan Beulich 1 week ago
On 20.02.2026 22:46, Andrew Cooper wrote:
> Eclair complains that tboot_gen_domain_integrity() is casting away
> constness (Rule 11.8 violation).
> 
> vmac_set_key() doesn't modify the user_key parameter, so it can become const,
> removing the need to cast.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>