sparse_array: avoid ubsan violation in typed doall

clang-22 with enable-asan and enable-ubsan enabled fails with error

  crypto/sparse_array.c:93:21: runtime error: call to function alg_copy
  through pointer to incorrect function type 'void (*)(unsigned long, void *, void *)'

    ossl_sa_##type##_doall(const SPARSE_ARRAY_OF(type) * sa,
        void (*leaf)(ossl_uintmax_t, type *))
    {
        ossl_sa_doall((OPENSSL_SA *)sa,
            (void (*)(ossl_uintmax_t, void *))leaf);
    }

typed doall(_arg) expect leaf to have type, but generic code is using
void *, and the type-casting cases the error.

Signed-off-by: Nikola Pajkovsky <nikolap@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
MergeDate: Sun May  3 15:17:58 2026
(Merged from https://github.com/openssl/openssl/pull/31035)

diff --git a/include/crypto/sparse_array.h b/include/crypto/sparse_array.h
index d452bfbe06f15dad2219d8e2550d2fdfdc321ff9..d77a46ebfa89fc65a693d8cea77012092be85415 100644 (file)
--- a/include/crypto/sparse_array.h
+++ b/include/crypto/sparse_array.h
@@ -22,6 +22,8 @@ extern "C" {
 
 #define DEFINE_SPARSE_ARRAY_OF_INTERNAL(type, ctype)                                                               \
     SPARSE_ARRAY_OF(type);                                                                                         \
+    typedef void (*sa_##type##_leaffunc)(ossl_uintmax_t idx, type *t);                                             \
+    typedef void (*sa_##type##_leaffunc_arg)(ossl_uintmax_t idx, type *t, void *arg);                              \
     static ossl_unused ossl_inline SPARSE_ARRAY_OF(type) * ossl_sa_##type##_new(void)                              \
     {                                                                                                              \
         return (SPARSE_ARRAY_OF(type) *)ossl_sa_new();                                                             \
@@ -41,20 +43,40 @@ extern "C" {
     {                                                                                                              \
         return ossl_sa_num((OPENSSL_SA *)sa);                                                                      \
     }                                                                                                              \
+    static ossl_unused void                                                                                        \
+    ossl_sa_##type##_doall_thunk(ossl_uintmax_t idx, void *leaf, void *arg)                                        \
+    {                                                                                                              \
+        sa_##type##_leaffunc fn = *(sa_##type##_leaffunc *)arg;                                                    \
+        (*fn)(idx, (type *)leaf);                                                                                  \
+    }                                                                                                              \
     static ossl_unused ossl_inline void                                                                            \
     ossl_sa_##type##_doall(const SPARSE_ARRAY_OF(type) * sa,                                                       \
         void (*leaf)(ossl_uintmax_t, type *))                                                                      \
     {                                                                                                              \
-        ossl_sa_doall((OPENSSL_SA *)sa,                                                                            \
-            (void (*)(ossl_uintmax_t, void *))leaf);                                                               \
+        ossl_sa_doall_arg((OPENSSL_SA *)sa, ossl_sa_##type##_doall_thunk, &leaf);                                  \
+    }                                                                                                              \
+    struct ossl_sa_##type##_doall_thunk {                                                                          \
+        sa_##type##_leaffunc_arg fn;                                                                               \
+        void *arg;                                                                                                 \
+    };                                                                                                             \
+    static ossl_unused void                                                                                        \
+    ossl_sa_##type##_doall_arg_thunk(ossl_uintmax_t idx, void *leaf, void *arg)                                    \
+    {                                                                                                              \
+        struct ossl_sa_##type##_doall_thunk *t = arg;                                                              \
+                                                                                                                   \
+        (*t->fn)(idx, (type *)leaf, t->arg);                                                                       \
     }                                                                                                              \
     static ossl_unused ossl_inline void                                                                            \
     ossl_sa_##type##_doall_arg(const SPARSE_ARRAY_OF(type) * sa,                                                   \
         void (*leaf)(ossl_uintmax_t, type *, void *),                                                              \
         void *arg)                                                                                                 \
     {                                                                                                              \
+        struct ossl_sa_##type##_doall_thunk t;                                                                     \
+                                                                                                                   \
+        t.fn = leaf;                                                                                               \
+        t.arg = arg;                                                                                               \
         ossl_sa_doall_arg((OPENSSL_SA *)sa,                                                                        \
-            (void (*)(ossl_uintmax_t, void *, void *))leaf, arg);                                                  \
+            ossl_sa_##type##_doall_arg_thunk, &t);                                                                 \
     }                                                                                                              \
     static ossl_unused ossl_inline ctype *ossl_sa_##type##_get(const SPARSE_ARRAY_OF(type) * sa, ossl_uintmax_t n) \
     {                                                                                                              \