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Diffstat (limited to 'scripts/gcc-plugins/randomize_layout_plugin.c')
-rw-r--r--scripts/gcc-plugins/randomize_layout_plugin.c161
1 files changed, 25 insertions, 136 deletions
diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c
index bd29e4e7a524..ff65a4f87f24 100644
--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -19,10 +19,6 @@
#include "gcc-common.h"
#include "randomize_layout_seed.h"
-#if BUILDING_GCC_MAJOR < 4 || (BUILDING_GCC_MAJOR == 4 && BUILDING_GCC_MINOR < 7)
-#error "The RANDSTRUCT plugin requires GCC 4.7 or newer."
-#endif
-
#define ORIG_TYPE_NAME(node) \
(TYPE_NAME(TYPE_MAIN_VARIANT(node)) != NULL_TREE ? ((const unsigned char *)IDENTIFIER_POINTER(TYPE_NAME(TYPE_MAIN_VARIANT(node)))) : (const unsigned char *)"anonymous")
@@ -34,29 +30,11 @@ __visible int plugin_is_GPL_compatible;
static int performance_mode;
static struct plugin_info randomize_layout_plugin_info = {
- .version = "201402201816vanilla",
+ .version = PLUGIN_VERSION,
.help = "disable\t\t\tdo not activate plugin\n"
"performance-mode\tenable cacheline-aware layout randomization\n"
};
-struct whitelist_entry {
- const char *pathname;
- const char *lhs;
- const char *rhs;
-};
-
-static const struct whitelist_entry whitelist[] = {
- /* NIU overloads mapping with page struct */
- { "drivers/net/ethernet/sun/niu.c", "page", "address_space" },
- /* unix_skb_parms via UNIXCB() buffer */
- { "net/unix/af_unix.c", "unix_skb_parms", "char" },
- /* big_key payload.data struct splashing */
- { "security/keys/big_key.c", "path", "void *" },
- /* walk struct security_hook_heads as an array of struct hlist_head */
- { "security/security.c", "hlist_head", "security_hook_heads" },
- { }
-};
-
/* from old Linux dcache.h */
static inline unsigned long
partial_name_hash(unsigned long c, unsigned long prevhash)
@@ -95,6 +73,9 @@ 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);
@@ -209,12 +190,14 @@ static void partition_struct(tree *fields, unsigned long length, struct partitio
static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prng_state)
{
- unsigned long i, x;
+ unsigned long i, x, index;
struct partition_group size_group[length];
unsigned long num_groups = 0;
unsigned long randnum;
partition_struct(newtree, length, (struct partition_group *)&size_group, &num_groups);
+
+ /* FIXME: this group shuffle is currently a no-op. */
for (i = num_groups - 1; i > 0; i--) {
struct partition_group tmp;
randnum = ranval(prng_state) % (i + 1);
@@ -224,11 +207,14 @@ static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prn
}
for (x = 0; x < num_groups; x++) {
- for (i = size_group[x].start + size_group[x].length - 1; i > size_group[x].start; i--) {
+ for (index = size_group[x].length - 1; index > 0; index--) {
tree tmp;
+
+ i = size_group[x].start + index;
if (DECL_BIT_FIELD_TYPE(newtree[i]))
continue;
- randnum = ranval(prng_state) % (i + 1);
+ randnum = ranval(prng_state) % (index + 1);
+ randnum += size_group[x].start;
// we could handle this case differently if desired
if (DECL_BIT_FIELD_TYPE(newtree[randnum]))
continue;
@@ -291,8 +277,6 @@ static bool is_flexible_array(const_tree field)
{
const_tree fieldtype;
const_tree typesize;
- const_tree elemtype;
- const_tree elemsize;
fieldtype = TREE_TYPE(field);
typesize = TYPE_SIZE(fieldtype);
@@ -300,20 +284,12 @@ static bool is_flexible_array(const_tree field)
if (TREE_CODE(fieldtype) != ARRAY_TYPE)
return false;
- elemtype = TREE_TYPE(fieldtype);
- elemsize = TYPE_SIZE(elemtype);
-
/* size of type is represented in bits */
if (typesize == NULL_TREE && TYPE_DOMAIN(fieldtype) != NULL_TREE &&
TYPE_MAX_VALUE(TYPE_DOMAIN(fieldtype)) == NULL_TREE)
return true;
- if (typesize != NULL_TREE &&
- (TREE_CONSTANT(typesize) && (!tree_to_uhwi(typesize) ||
- tree_to_uhwi(typesize) == tree_to_uhwi(elemsize))))
- return true;
-
return false;
}
@@ -362,8 +338,7 @@ static int relayout_struct(tree type)
/*
* enforce that we don't randomize the layout of the last
- * element of a struct if it's a 0 or 1-length array
- * or a proper flexible array
+ * element of a struct if it's a proper flexible array
*/
if (is_flexible_array(newtree[num_fields - 1])) {
has_flexarray = true;
@@ -372,35 +347,18 @@ static int relayout_struct(tree type)
shuffle(type, (tree *)newtree, shuffle_length);
- /*
- * set up a bogus anonymous struct field designed to error out on unnamed struct initializers
- * as gcc provides no other way to detect such code
- */
- list = make_node(FIELD_DECL);
- TREE_CHAIN(list) = newtree[0];
- TREE_TYPE(list) = void_type_node;
- DECL_SIZE(list) = bitsize_zero_node;
- DECL_NONADDRESSABLE_P(list) = 1;
- DECL_FIELD_BIT_OFFSET(list) = bitsize_zero_node;
- DECL_SIZE_UNIT(list) = size_zero_node;
- DECL_FIELD_OFFSET(list) = size_zero_node;
- DECL_CONTEXT(list) = type;
- // to satisfy the constify plugin
- TREE_READONLY(list) = 1;
-
for (i = 0; i < num_fields - 1; i++)
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)) {
- TYPE_FIELDS(variant) = list;
- 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));
- }
+ for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant))
+ TYPE_FIELDS(variant) = newtree[0];
/*
* force a re-layout of the main variant
@@ -468,10 +426,8 @@ 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
@@ -590,16 +546,12 @@ static void register_attributes(void *event_data, void *data)
randomize_layout_attr.name = "randomize_layout";
randomize_layout_attr.type_required = true;
randomize_layout_attr.handler = handle_randomize_layout_attr;
-#if BUILDING_GCC_VERSION >= 4007
randomize_layout_attr.affects_type_identity = true;
-#endif
no_randomize_layout_attr.name = "no_randomize_layout";
no_randomize_layout_attr.type_required = true;
no_randomize_layout_attr.handler = handle_randomize_layout_attr;
-#if BUILDING_GCC_VERSION >= 4007
no_randomize_layout_attr.affects_type_identity = true;
-#endif
randomize_considered_attr.name = "randomize_considered";
randomize_considered_attr.type_required = true;
@@ -746,60 +698,6 @@ static void handle_local_var_initializers(void)
}
}
-static bool type_name_eq(gimple stmt, const_tree type_tree, const char *wanted_name)
-{
- const char *type_name;
-
- if (type_tree == NULL_TREE)
- return false;
-
- switch (TREE_CODE(type_tree)) {
- case RECORD_TYPE:
- type_name = TYPE_NAME_POINTER(type_tree);
- break;
- case INTEGER_TYPE:
- if (TYPE_PRECISION(type_tree) == CHAR_TYPE_SIZE)
- type_name = "char";
- else {
- INFORM(gimple_location(stmt), "found non-char INTEGER_TYPE cast comparison: %qT\n", type_tree);
- debug_tree(type_tree);
- return false;
- }
- break;
- case POINTER_TYPE:
- if (TREE_CODE(TREE_TYPE(type_tree)) == VOID_TYPE) {
- type_name = "void *";
- break;
- } else {
- INFORM(gimple_location(stmt), "found non-void POINTER_TYPE cast comparison %qT\n", type_tree);
- debug_tree(type_tree);
- return false;
- }
- default:
- INFORM(gimple_location(stmt), "unhandled cast comparison: %qT\n", type_tree);
- debug_tree(type_tree);
- return false;
- }
-
- return strcmp(type_name, wanted_name) == 0;
-}
-
-static bool whitelisted_cast(gimple stmt, const_tree lhs_tree, const_tree rhs_tree)
-{
- const struct whitelist_entry *entry;
- expanded_location xloc = expand_location(gimple_location(stmt));
-
- for (entry = whitelist; entry->pathname; entry++) {
- if (!strstr(xloc.file, entry->pathname))
- continue;
-
- if (type_name_eq(stmt, lhs_tree, entry->lhs) && type_name_eq(stmt, rhs_tree, entry->rhs))
- return true;
- }
-
- return false;
-}
-
/*
* iterate over all statements to find "bad" casts:
* those where the address of the start of a structure is cast
@@ -876,10 +774,7 @@ static unsigned int find_bad_casts_execute(void)
#ifndef __DEBUG_PLUGIN
if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_lhs_type)))
#endif
- {
- if (!whitelisted_cast(stmt, ptr_lhs_type, ptr_rhs_type))
- MISMATCH(gimple_location(stmt), "rhs", ptr_lhs_type, ptr_rhs_type);
- }
+ MISMATCH(gimple_location(stmt), "rhs", ptr_lhs_type, ptr_rhs_type);
continue;
}
@@ -902,10 +797,7 @@ static unsigned int find_bad_casts_execute(void)
#ifndef __DEBUG_PLUGIN
if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(op0_type)))
#endif
- {
- if (!whitelisted_cast(stmt, ptr_lhs_type, op0_type))
- MISMATCH(gimple_location(stmt), "op0", ptr_lhs_type, op0_type);
- }
+ MISMATCH(gimple_location(stmt), "op0", ptr_lhs_type, op0_type);
} else {
const_tree ssa_name_var = SSA_NAME_VAR(rhs1);
/* skip bogus type casts introduced by container_of */
@@ -915,10 +807,7 @@ static unsigned int find_bad_casts_execute(void)
#ifndef __DEBUG_PLUGIN
if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_rhs_type)))
#endif
- {
- if (!whitelisted_cast(stmt, ptr_lhs_type, ptr_rhs_type))
- MISMATCH(gimple_location(stmt), "ssa", ptr_lhs_type, ptr_rhs_type);
- }
+ MISMATCH(gimple_location(stmt), "ssa", ptr_lhs_type, ptr_rhs_type);
}
}
generated by cgit (git 2.34.1) at 2025-12-21 18:56:38 +0000