From: Kees Cook kees@kernel.org
[ Upstream commit f39f18f3c3531aa802b58a20d39d96e82eb96c14 ]
Based on changes in the 2021 public version of the randstruct out-of-tree GCC plugin[1], more carefully update the attributes on resulting decls, to avoid tripping checks in GCC 15's comptypes_check_enum_int() when it has been configured with "--enable-checking=misc":
arch/arm64/kernel/kexec_image.c:132:14: internal compiler error: in comptypes_check_enum_int, at c/c-typeck.cc:1519 132 | const struct kexec_file_ops kexec_image_ops = { | ^~~~~~~~~~~~~~ internal_error(char const*, ...), at gcc/gcc/diagnostic-global-context.cc:517 fancy_abort(char const*, int, char const*), at gcc/gcc/diagnostic.cc:1803 comptypes_check_enum_int(tree_node*, tree_node*, bool*), at gcc/gcc/c/c-typeck.cc:1519 ...
Link: https://archive.org/download/grsecurity/grsecurity-3.1-5.10.41-202105280954.... [1] Reported-by: Thiago Jung Bauermann thiago.bauermann@linaro.org Closes: https://github.com/KSPP/linux/issues/367 Closes: https://lore.kernel.org/lkml/20250530000646.104457-1-thiago.bauermann@linaro... Reported-by: Ingo Saitz ingo@hannover.ccc.de Closes: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1104745 Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin") Tested-by: Thiago Jung Bauermann thiago.bauermann@linaro.org Link: https://lore.kernel.org/r/20250530221824.work.623-kees@kernel.org Signed-off-by: Kees Cook kees@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- scripts/gcc-plugins/gcc-common.h | 32 +++++++++++++++++++ scripts/gcc-plugins/randomize_layout_plugin.c | 22 ++++++------- 2 files changed, 43 insertions(+), 11 deletions(-)
diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h index 0907ab19202a1..6ec887ae71b64 100644 --- a/scripts/gcc-plugins/gcc-common.h +++ b/scripts/gcc-plugins/gcc-common.h @@ -182,6 +182,38 @@ static inline tree build_const_char_string(int len, const char *str) return cstr; }
+static inline void __add_type_attr(tree type, const char *attr, tree args) +{ + tree oldattr; + + if (type == NULL_TREE) + return; + oldattr = lookup_attribute(attr, TYPE_ATTRIBUTES(type)); + if (oldattr != NULL_TREE) { + gcc_assert(TREE_VALUE(oldattr) == args || TREE_VALUE(TREE_VALUE(oldattr)) == TREE_VALUE(args)); + return; + } + + TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type)); + TYPE_ATTRIBUTES(type) = tree_cons(get_identifier(attr), args, TYPE_ATTRIBUTES(type)); +} + +static inline void add_type_attr(tree type, const char *attr, tree args) +{ + tree main_variant = TYPE_MAIN_VARIANT(type); + + __add_type_attr(TYPE_CANONICAL(type), attr, args); + __add_type_attr(TYPE_CANONICAL(main_variant), attr, args); + __add_type_attr(main_variant, attr, args); + + for (type = TYPE_NEXT_VARIANT(main_variant); type; type = TYPE_NEXT_VARIANT(type)) { + if (!lookup_attribute(attr, TYPE_ATTRIBUTES(type))) + TYPE_ATTRIBUTES(type) = TYPE_ATTRIBUTES(main_variant); + + __add_type_attr(TYPE_CANONICAL(type), attr, args); + } +} + #define PASS_INFO(NAME, REF, ID, POS) \ struct register_pass_info NAME##_pass_info = { \ .pass = make_##NAME##_pass(), \ diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c index a5aea51ecca99..472427f169a4a 100644 --- a/scripts/gcc-plugins/randomize_layout_plugin.c +++ b/scripts/gcc-plugins/randomize_layout_plugin.c @@ -95,6 +95,9 @@ static tree handle_randomize_layout_attr(tree *node, tree name, tree args, int f
if (TYPE_P(*node)) { type = *node; + } else if (TREE_CODE(*node) == FIELD_DECL) { + *no_add_attrs = false; + return NULL_TREE; } else { gcc_assert(TREE_CODE(*node) == TYPE_DECL); type = TREE_TYPE(*node); @@ -381,15 +384,14 @@ static int relayout_struct(tree type) TREE_CHAIN(newtree[i]) = newtree[i+1]; TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE;
+ add_type_attr(type, "randomize_performed", NULL_TREE); + add_type_attr(type, "designated_init", NULL_TREE); + if (has_flexarray) + add_type_attr(type, "has_flexarray", NULL_TREE); + main_variant = TYPE_MAIN_VARIANT(type); - for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) { + for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) TYPE_FIELDS(variant) = newtree[0]; - TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant)); - TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant)); - TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant)); - if (has_flexarray) - TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("has_flexarray"), NULL_TREE, TYPE_ATTRIBUTES(type)); - }
/* * force a re-layout of the main variant @@ -457,10 +459,8 @@ static void randomize_type(tree type) if (lookup_attribute("randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type))) || is_pure_ops_struct(type)) relayout_struct(type);
- for (variant = TYPE_MAIN_VARIANT(type); variant; variant = TYPE_NEXT_VARIANT(variant)) { - TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type)); - TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("randomize_considered"), NULL_TREE, TYPE_ATTRIBUTES(type)); - } + add_type_attr(type, "randomize_considered", NULL_TREE); + #ifdef __DEBUG_PLUGIN fprintf(stderr, "Marking randomize_considered on struct %s\n", ORIG_TYPE_NAME(type)); #ifdef __DEBUG_VERBOSE