[common] Update UBSan to be compatible with Clang 18

common/src/avl_tree.c

@@ -514,6 +514,16 @@ struct avl_tree_node* avl_tree_find(struct avl_tree* tree, struct avl_tree_node*
     return avl_tree_find_fn_to(tree, node, tree->cmp);
 }
 
+#ifdef UBSAN
+/*
+ * Function pointer cmp is of type `bool (*)(void*, struct avl_tree_node*)` but the caller
+ * avl_tree_lower_bound() passes cmp as `bool (*)(struct avl_tree_node*, struct avl_tree_node*)`.
+ * UBSan complains about "Indirect call of a function through a function pointer of the wrong type"
+ * because of this mismatch. However, allowing the first argument to be a pointer to any type was
+ * done on purpose; see corresponding comment in avl_tree.h. So, silence this particular complaint.
+ */
+__attribute__((no_sanitize("function")))
+#endif
 struct avl_tree_node* avl_tree_lower_bound_fn(struct avl_tree* tree, void* cmp_arg,
                                               bool cmp(void*, struct avl_tree_node*)) {
     struct avl_tree_node* node = tree->root;

common/src/ubsan.c

@@ -26,6 +26,11 @@
 
 /* Type definitions (adapted from libubsan) */
 
+/*
+ * NOTE: TypeDescriptor contains information about the type of the variable/function, in particular,
+ * `char* TypeName`. Unfortunately, TypeDescriptor is implemented as C++ class in GCC/Clang so we
+ * can't easily represent it in C. Thus, we declare it as opaque struct and can't use TypeName.
+ */
 struct type_descriptor;
 
 struct source_location {
@@ -41,6 +46,11 @@ struct type_mismatch_data {
     uint8_t type_check_kind;
 };
 
+struct function_type_mismatch_data {
+    struct source_location loc;
+    const struct type_descriptor* type;
+};
+
 typedef uintptr_t value_handle;
 
 static void ubsan_log_location(struct source_location* loc) {
@@ -131,6 +141,7 @@ UBSAN_SIMPLE_HANDLER_1(invalid_builtin,
 
 /* More complex handlers, displaying additional information. */
 
+/* type mismatch handlers */
 void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data* data, value_handle pointer);
 void __ubsan_handle_type_mismatch_v1_abort(struct type_mismatch_data* data, value_handle pointer);
 
@@ -151,3 +162,28 @@ void __ubsan_handle_type_mismatch_v1_abort(struct type_mismatch_data* data, valu
     __ubsan_handle_type_mismatch_v1(data, pointer);
     abort();
 }
+
+/* function type mismatch handlers */
+void __ubsan_handle_function_type_mismatch(struct function_type_mismatch_data* data,
+                                           value_handle function_pointer);
+void __ubsan_handle_function_type_mismatch_abort(struct function_type_mismatch_data* data,
+                                                 value_handle function_pointer);
+
+void __ubsan_handle_function_type_mismatch(struct function_type_mismatch_data* data,
+                                           value_handle function_pointer) {
+    /*
+     * NOTE: UBSan in GCC/Clang prints "call to function {getSymbolizedLocation(function_pointer)}
+     * through pointer to incorrect function type {data->type->TypeName}". Unfortunately we can't
+     * learn the name of the func based on the address, and we can't use TypeName (see comment at
+     * the top of this file).
+     */
+    log_error("ubsan: call to function at 0x%lx through pointer to incorrect function type",
+              function_pointer);
+    ubsan_log_location(&data->loc);
+}
+
+void __ubsan_handle_function_type_mismatch_abort(struct function_type_mismatch_data* data,
+                                                 value_handle function_pointer) {
+    __ubsan_handle_function_type_mismatch(data, function_pointer);
+    abort();
+}

libos/src/fs/sys/fs.c

@@ -77,7 +77,7 @@ int sys_print_as_bitmask(char* buf, size_t buf_size, size_t count,
     uint32_t word = 0;
     while (1) {
         if (is_present(pos, callback_arg))
-            word |= 1 << pos % 32;
+            word |= 1U << pos % 32;
         if (pos % 32 == 0) {
             if (count <= 32) {
                 /* Linux sysfs quirk: small bitmasks are printed without leading zeroes. */

libos/src/libos_syscalls.c

@@ -23,6 +23,14 @@ typedef arch_syscall_arg_t (*six_args_syscall_t)(arch_syscall_arg_t, arch_syscal
  * `context` is expected to be placed at the bottom of Gramine-internal stack.
  * If you change this function please also look at `libos_syscall_rt_sigsuspend`!
  */
+#ifdef UBSAN
+/*
+ * Variable syscall_func is of type six_args_syscall_t but points to item inside libos_syscall_table
+ * array, which has a type libos_syscall_t, thus UBSan complains about "Indirect call of a function
+ * through a function pointer of the wrong type". Silence this particular complaint.
+ */
+__attribute__((no_sanitize("function")))
+#endif
 noreturn void libos_emulate_syscall(PAL_CONTEXT* context) {
     LIBOS_TCB_SET(context.regs, context);
 

libos/src/net/unix.c

@@ -319,8 +319,7 @@ static int getsockopt(struct libos_handle* handle, int level, int optname, void*
 }
 
 static int maybe_force_nonblocking_wrapper(bool force_nonblocking, struct libos_handle* handle,
-                                           PAL_HANDLE pal_handle,
-                                           int (*func)(PAL_HANDLE, uint64_t, size_t*, void*),
+                                           PAL_HANDLE pal_handle, bool is_pal_stream_read,
                                            void* buf, size_t* size) {
     /*
      * There are 3 kinds of operations that can race here:
@@ -367,7 +366,11 @@ static int maybe_force_nonblocking_wrapper(bool force_nonblocking, struct libos_
     }
 
 again:
-    ret = func(pal_handle, /*offset=*/0, size, buf);
+    if (is_pal_stream_read) {
+        ret = PalStreamRead(pal_handle, /*offset=*/0, size, buf);
+    } else {
+        ret = PalStreamWrite(pal_handle, /*offset=*/0, size, buf);
+    }
     if (ret < 0) {
         ret = (ret == -PAL_ERROR_TOOLONG) ? -EMSGSIZE : pal_to_unix_errno(ret);
         if (ret == -EAGAIN && !force_nonblocking) {
@@ -475,8 +478,8 @@ static int send(struct libos_handle* handle, struct iovec* iov, size_t iov_len,
         /* `size` is already correct. */
     }
 
-    int ret = maybe_force_nonblocking_wrapper(force_nonblocking, handle, pal_handle, PalStreamWrite,
-                                              buf, &size);
+    int ret = maybe_force_nonblocking_wrapper(force_nonblocking, handle, pal_handle,
+                                              /*is_pal_stream_read=*/false, buf, &size);
     free(backing_buf);
     if (ret < 0) {
         return ret;
@@ -521,8 +524,8 @@ static int recv(struct libos_handle* handle, struct iovec* iov, size_t iov_len,
         /* `size` is already correct. */
     }
 
-    int ret = maybe_force_nonblocking_wrapper(force_nonblocking, handle, pal_handle, PalStreamRead,
-                                              buf, &size);
+    int ret = maybe_force_nonblocking_wrapper(force_nonblocking, handle, pal_handle,
+                                              /*is_pal_stream_read=*/true, buf, &size);
     if (ret == 0) {
         if (backing_buf) {
             /* Need to copy back to user buffers. */

pal/src/host/linux-sgx/pal_main.c

@@ -903,7 +903,7 @@ noreturn void pal_linux_main(void* uptr_libpal_uri, size_t libpal_uri_len, void*
     }
 
     init_handle_hdr(first_thread, PAL_TYPE_THREAD);
-    first_thread->thread.tcs = (void*)(g_enclave_base + GET_ENCLAVE_TCB(tcs_offset));
+    first_thread->thread.tcs = (void*)((uintptr_t)g_enclave_base + GET_ENCLAVE_TCB(tcs_offset));
     g_pal_public_state.first_thread = first_thread;
     SET_ENCLAVE_TCB(thread, &first_thread->thread);
 

pal/src/pal_rtld.c

@@ -404,7 +404,7 @@ static int perform_relocations(struct link_map* map) {
     }
 
     /* perform PLT relocs: supported binaries may have only R_X86_64_JUMP_SLOT relas */
-    elf_rela_t* plt_relas_addr_end = (void*)plt_relas_addr + plt_relas_size;
+    elf_rela_t* plt_relas_addr_end = (elf_rela_t*)((uintptr_t)plt_relas_addr + plt_relas_size);
     for (elf_rela_t* plt_rela = plt_relas_addr; plt_rela < plt_relas_addr_end; plt_rela++) {
         if (ELF_R_TYPE(plt_rela->r_info) != R_X86_64_JUMP_SLOT) {
             log_error("Unrecognized relocation type; PAL loader currently supports only "