Merge pull request #1634 from pguyot/w16/fix-unaligned-accesses-for-modules

bettio · bettio · commit 95ac53cb10e5 · 2025-04-19T14:37:44.000+02:00
Fix read 32 bits accesses to modules to be unaligned

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
diff --git a/.github/workflows/build-and-test-other.yaml b/.github/workflows/build-and-test-other.yaml
@@ -94,7 +94,7 @@ jobs:
 
         - arch: "arm32v7"
           platform: "arm/v7"
-          tag: "bullseye"
+          tag: "bookworm"
           # -D_FILE_OFFSET_BITS=64 is required for making atomvm:posix_readdir/1 test work
           # otherwise readdir will fail due to 64 bits inode numbers with 32 bit ino_t
           cflags: "-mcpu=cortex-a7 -mfloat-abi=hard -O2 -mthumb -mthumb-interwork -D_FILE_OFFSET_BITS=64"
diff --git a/src/libAtomVM/iff.c b/src/libAtomVM/iff.c
@@ -50,7 +50,7 @@ void scan_iff(const void *iff_binary, int buf_size, unsigned long *offsets, unsi
 
     int current_pos = 12;
 
-    uint32_t iff_size = READ_32_ALIGNED(data + 4);
+    uint32_t iff_size = READ_32_UNALIGNED(data + 4);
     int file_size = iff_size;
     if (UNLIKELY(buf_size < file_size)) {
         fprintf(stderr, "error: buffer holding IFF is smaller than IFF size: %i\n", buf_size);
diff --git a/src/libAtomVM/module.c b/src/libAtomVM/module.c
@@ -64,7 +64,8 @@ static void module_parse_line_table(Module *mod, const uint8_t *data, size_t len
 
 static enum ModuleLoadResult module_populate_atoms_table(Module *this_module, uint8_t *table_data, GlobalContext *glb)
 {
-    int atoms_count = READ_32_ALIGNED(table_data + 8);
+    int atoms_count = READ_32_UNALIGNED(table_data + 8);
+
     const char *current_atom = (const char *) table_data + 12;
 
     this_module->local_atoms_to_global_table = calloc(atoms_count + 1, sizeof(int));
@@ -85,7 +86,7 @@ static enum ModuleLoadResult module_populate_atoms_table(Module *this_module, ui
 
 static enum ModuleLoadResult module_build_imported_functions_table(Module *this_module, uint8_t *table_data, GlobalContext *glb)
 {
-    int functions_count = READ_32_ALIGNED(table_data + 8);
+    int functions_count = READ_32_UNALIGNED(table_data + 8);
 
     this_module->imported_funcs = calloc(functions_count, sizeof(struct ExportedFunction *));
     if (IS_NULL_PTR(this_module->imported_funcs)) {
@@ -94,11 +95,11 @@ static enum ModuleLoadResult module_build_imported_functions_table(Module *this_
     }
 
     for (int i = 0; i < functions_count; i++) {
-        int local_module_atom_index = READ_32_ALIGNED(table_data + i * 12 + 12);
-        int local_function_atom_index = READ_32_ALIGNED(table_data + i * 12 + 4 + 12);
+        int local_module_atom_index = READ_32_UNALIGNED(table_data + i * 12 + 12);
+        int local_function_atom_index = READ_32_UNALIGNED(table_data + i * 12 + 4 + 12);
         AtomString module_atom = module_get_atom_string_by_id(this_module, local_module_atom_index, glb);
         AtomString function_atom = module_get_atom_string_by_id(this_module, local_function_atom_index, glb);
-        uint32_t arity = READ_32_ALIGNED(table_data + i * 12 + 8 + 12);
+        uint32_t arity = READ_32_UNALIGNED(table_data + i * 12 + 8 + 12);
 
         const struct ExportedFunction *bif = bif_registry_get_handler(module_atom, function_atom, arity);
 
@@ -130,13 +131,13 @@ static enum ModuleLoadResult module_build_imported_functions_table(Module *this_
 void module_get_imported_function_module_and_name(const Module *this_module, int index, AtomString *module_atom, AtomString *function_atom, GlobalContext *glb)
 {
     const uint8_t *table_data = (const uint8_t *) this_module->import_table;
-    int functions_count = READ_32_ALIGNED(table_data + 8);
+    int functions_count = READ_32_UNALIGNED(table_data + 8);
 
     if (UNLIKELY(index > functions_count)) {
         AVM_ABORT();
     }
-    int local_module_atom_index = READ_32_ALIGNED(table_data + index * 12 + 12);
-    int local_function_atom_index = READ_32_ALIGNED(table_data + index * 12 + 4 + 12);
+    int local_module_atom_index = READ_32_UNALIGNED(table_data + index * 12 + 12);
+    int local_function_atom_index = READ_32_UNALIGNED(table_data + index * 12 + 4 + 12);
     *module_atom = module_get_atom_string_by_id(this_module, local_module_atom_index, glb);
     *function_atom = module_get_atom_string_by_id(this_module, local_function_atom_index, glb);
 }
@@ -146,11 +147,11 @@ bool module_get_function_from_label(Module *this_module, int label, AtomString *
 {
     int best_label = -1;
     const uint8_t *export_table_data = (const uint8_t *) this_module->export_table;
-    int exports_count = READ_32_ALIGNED(export_table_data + 8);
+    int exports_count = READ_32_UNALIGNED(export_table_data + 8);
     for (int export_index = exports_count - 1; export_index >= 0; export_index--) {
-        int fun_atom_index = READ_32_ALIGNED(export_table_data + (export_index * 12) + 12);
-        int fun_arity = READ_32_ALIGNED(export_table_data + (export_index * 12) + 4 + 12);
-        int fun_label = READ_32_ALIGNED(export_table_data + (export_index * 12) + 8 + 12);
+        int fun_atom_index = READ_32_UNALIGNED(export_table_data + (export_index * 12) + 12);
+        int fun_arity = READ_32_UNALIGNED(export_table_data + (export_index * 12) + 4 + 12);
+        int fun_label = READ_32_UNALIGNED(export_table_data + (export_index * 12) + 8 + 12);
         if (fun_label <= label && best_label < fun_label) {
             best_label = fun_label;
             *arity = fun_arity;
@@ -159,11 +160,11 @@ bool module_get_function_from_label(Module *this_module, int label, AtomString *
     }
 
     const uint8_t *local_table_data = (const uint8_t *) this_module->local_table;
-    int locals_count = READ_32_ALIGNED(local_table_data + 8);
+    int locals_count = READ_32_UNALIGNED(local_table_data + 8);
     for (int local_index = locals_count - 1; local_index >= 0; local_index--) {
-        int fun_atom_index = READ_32_ALIGNED(local_table_data + (local_index * 12) + 12);
-        int fun_arity = READ_32_ALIGNED(local_table_data + (local_index * 12) + 4 + 12);
-        int fun_label = READ_32_ALIGNED(local_table_data + (local_index * 12) + 8 + 12);
+        int fun_atom_index = READ_32_UNALIGNED(local_table_data + (local_index * 12) + 12);
+        int fun_arity = READ_32_UNALIGNED(local_table_data + (local_index * 12) + 4 + 12);
+        int fun_label = READ_32_UNALIGNED(local_table_data + (local_index * 12) + 8 + 12);
         if (fun_label <= label && best_label < fun_label) {
             best_label = fun_label;
             *arity = fun_arity;
@@ -180,7 +181,7 @@ bool module_get_function_from_label(Module *this_module, int label, AtomString *
 size_t module_get_exported_functions_count(Module *this_module)
 {
     const uint8_t *table_data = (const uint8_t *) this_module->export_table;
-    size_t functions_count = READ_32_ALIGNED(table_data + 8);
+    size_t functions_count = READ_32_UNALIGNED(table_data + 8);
     return functions_count;
 }
 
@@ -190,10 +191,10 @@ uint32_t module_search_exported_function(Module *this_module, AtomString func_na
 
     const uint8_t *table_data = (const uint8_t *) this_module->export_table;
     for (unsigned int i = 0; i < functions_count; i++) {
-        AtomString function_atom = module_get_atom_string_by_id(this_module, READ_32_ALIGNED(table_data + i * 12 + 12), glb);
-        int32_t arity = READ_32_ALIGNED(table_data + i * 12 + 4 + 12);
+        AtomString function_atom = module_get_atom_string_by_id(this_module, READ_32_UNALIGNED(table_data + i * 12 + 12), glb);
+        int32_t arity = READ_32_UNALIGNED(table_data + i * 12 + 4 + 12);
         if ((func_arity == arity) && atom_are_equals(func_name, function_atom)) {
-            uint32_t label = READ_32_ALIGNED(table_data + i * 12 + 8 + 12);
+            uint32_t label = READ_32_UNALIGNED(table_data + i * 12 + 8 + 12);
             return label;
         }
     }
@@ -208,8 +209,8 @@ term module_get_exported_functions(Module *this_module, Heap *heap, GlobalContex
 
     const uint8_t *table_data = (const uint8_t *) this_module->export_table;
     for (unsigned int i = 0; i < functions_count; i++) {
-        AtomString function_atom = module_get_atom_string_by_id(this_module, READ_32_ALIGNED(table_data + i * 12 + 12), glb);
-        int32_t arity = READ_32_ALIGNED(table_data + i * 12 + 4 + 12);
+        AtomString function_atom = module_get_atom_string_by_id(this_module, READ_32_UNALIGNED(table_data + i * 12 + 12), glb);
+        int32_t arity = READ_32_UNALIGNED(table_data + i * 12 + 4 + 12);
         term function_tuple = term_alloc_tuple(2, heap);
         term_put_tuple_element(function_tuple, 0, globalcontext_existing_term_from_atom_string(glb, function_atom));
         term_put_tuple_element(function_tuple, 1, term_from_int(arity));
@@ -327,7 +328,7 @@ COLD_FUNC void module_destroy(Module *module)
 #ifdef WITH_ZLIB
 static void *module_uncompress_literals(const uint8_t *litT, int size)
 {
-    unsigned int required_buf_size = READ_32_ALIGNED(litT + LITT_UNCOMPRESSED_SIZE_OFFSET);
+    unsigned int required_buf_size = READ_32_UNALIGNED(litT + LITT_UNCOMPRESSED_SIZE_OFFSET);
 
     uint8_t *outBuf = malloc(required_buf_size);
     if (IS_NULL_PTR(outBuf)) {
@@ -362,7 +363,7 @@ static void *module_uncompress_literals(const uint8_t *litT, int size)
 
 static struct LiteralEntry *module_build_literals_table(const void *literalsBuf)
 {
-    uint32_t terms_count = READ_32_ALIGNED(literalsBuf);
+    uint32_t terms_count = READ_32_UNALIGNED(literalsBuf);
 
     const uint8_t *pos = (const uint8_t *) literalsBuf + sizeof(uint32_t);
 
diff --git a/src/libAtomVM/module.h b/src/libAtomVM/module.h
@@ -323,7 +323,7 @@ static inline term module_address(unsigned int module_index, unsigned int instru
 static inline uint32_t module_get_fun_freeze(const Module *this_module, int fun_index)
 {
     const uint8_t *table_data = (const uint8_t *) this_module->fun_table;
-    int funs_count = READ_32_ALIGNED(table_data + 8);
+    int funs_count = READ_32_UNALIGNED(table_data + 8);
 
     if (UNLIKELY(fun_index >= funs_count)) {
         AVM_ABORT();
@@ -333,7 +333,7 @@ static inline uint32_t module_get_fun_freeze(const Module *this_module, int fun_
     // arity
     // label
     // index
-    uint32_t n_freeze = READ_32_ALIGNED(table_data + fun_index * 24 + 16 + 12);
+    uint32_t n_freeze = READ_32_UNALIGNED(table_data + fun_index * 24 + 16 + 12);
     // ouniq
 
     return n_freeze;
@@ -342,17 +342,17 @@ static inline uint32_t module_get_fun_freeze(const Module *this_module, int fun_
 static inline void module_get_fun(const Module *this_module, int fun_index, uint32_t *label, uint32_t *arity, uint32_t *n_freeze)
 {
     const uint8_t *table_data = (const uint8_t *) this_module->fun_table;
-    int funs_count = READ_32_ALIGNED(table_data + 8);
+    int funs_count = READ_32_UNALIGNED(table_data + 8);
 
     if (UNLIKELY(fun_index >= funs_count)) {
         AVM_ABORT();
     }
 
     // fun atom index
-    *arity = READ_32_ALIGNED(table_data + fun_index * 24 + 4 + 12);
-    *label = READ_32_ALIGNED(table_data + fun_index * 24 + 8 + 12);
+    *arity = READ_32_UNALIGNED(table_data + fun_index * 24 + 4 + 12);
+    *label = READ_32_UNALIGNED(table_data + fun_index * 24 + 8 + 12);
     // index
-    *n_freeze = READ_32_ALIGNED(table_data + fun_index * 24 + 16 + 12);
+    *n_freeze = READ_32_UNALIGNED(table_data + fun_index * 24 + 16 + 12);
     // ouniq
 }
 
