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907 lines
24 KiB
907 lines
24 KiB
/* |
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* Copyright 2014-2016 by Open Source Security, Inc., Brad Spengler <[email protected]> |
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* and PaX Team <[email protected]> |
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* Licensed under the GPL v2 |
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* |
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* Note: the choice of the license means that the compilation process is |
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* NOT 'eligible' as defined by gcc's library exception to the GPL v3, |
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* but for the kernel it doesn't matter since it doesn't link against |
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* any of the gcc libraries |
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* |
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* Usage: |
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* $ # for 4.5/4.6/C based 4.7 |
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* $ gcc -I`gcc -print-file-name=plugin`/include -I`gcc -print-file-name=plugin`/include/c-family -fPIC -shared -O2 -o randomize_layout_plugin.so randomize_layout_plugin.c |
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* $ # for C++ based 4.7/4.8+ |
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* $ g++ -I`g++ -print-file-name=plugin`/include -I`g++ -print-file-name=plugin`/include/c-family -fPIC -shared -O2 -o randomize_layout_plugin.so randomize_layout_plugin.c |
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* $ gcc -fplugin=./randomize_layout_plugin.so test.c -O2 |
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*/ |
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#include "gcc-common.h" |
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#include "randomize_layout_seed.h" |
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#if BUILDING_GCC_MAJOR < 4 || (BUILDING_GCC_MAJOR == 4 && BUILDING_GCC_MINOR < 7) |
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#error "The RANDSTRUCT plugin requires GCC 4.7 or newer." |
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#endif |
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#define ORIG_TYPE_NAME(node) \ |
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(TYPE_NAME(TYPE_MAIN_VARIANT(node)) != NULL_TREE ? ((const unsigned char *)IDENTIFIER_POINTER(TYPE_NAME(TYPE_MAIN_VARIANT(node)))) : (const unsigned char *)"anonymous") |
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#define INFORM(loc, msg, ...) inform(loc, "randstruct: " msg, ##__VA_ARGS__) |
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#define MISMATCH(loc, how, ...) INFORM(loc, "casting between randomized structure pointer types (" how "): %qT and %qT\n", __VA_ARGS__) |
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__visible int plugin_is_GPL_compatible; |
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static int performance_mode; |
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|
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static struct plugin_info randomize_layout_plugin_info = { |
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.version = PLUGIN_VERSION, |
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.help = "disable\t\t\tdo not activate plugin\n" |
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"performance-mode\tenable cacheline-aware layout randomization\n" |
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}; |
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|
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/* from old Linux dcache.h */ |
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static inline unsigned long |
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partial_name_hash(unsigned long c, unsigned long prevhash) |
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{ |
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return (prevhash + (c << 4) + (c >> 4)) * 11; |
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} |
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static inline unsigned int |
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name_hash(const unsigned char *name) |
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{ |
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unsigned long hash = 0; |
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unsigned int len = strlen((const char *)name); |
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while (len--) |
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hash = partial_name_hash(*name++, hash); |
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return (unsigned int)hash; |
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} |
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|
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static tree handle_randomize_layout_attr(tree *node, tree name, tree args, int flags, bool *no_add_attrs) |
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{ |
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tree type; |
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*no_add_attrs = true; |
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if (TREE_CODE(*node) == FUNCTION_DECL) { |
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error("%qE attribute does not apply to functions (%qF)", name, *node); |
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return NULL_TREE; |
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} |
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if (TREE_CODE(*node) == PARM_DECL) { |
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error("%qE attribute does not apply to function parameters (%qD)", name, *node); |
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return NULL_TREE; |
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} |
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if (TREE_CODE(*node) == VAR_DECL) { |
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error("%qE attribute does not apply to variables (%qD)", name, *node); |
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return NULL_TREE; |
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} |
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if (TYPE_P(*node)) { |
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type = *node; |
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} else { |
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gcc_assert(TREE_CODE(*node) == TYPE_DECL); |
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type = TREE_TYPE(*node); |
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} |
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if (TREE_CODE(type) != RECORD_TYPE) { |
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error("%qE attribute used on %qT applies to struct types only", name, type); |
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return NULL_TREE; |
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} |
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if (lookup_attribute(IDENTIFIER_POINTER(name), TYPE_ATTRIBUTES(type))) { |
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error("%qE attribute is already applied to the type %qT", name, type); |
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return NULL_TREE; |
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} |
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*no_add_attrs = false; |
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return NULL_TREE; |
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} |
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/* set on complete types that we don't need to inspect further at all */ |
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static tree handle_randomize_considered_attr(tree *node, tree name, tree args, int flags, bool *no_add_attrs) |
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{ |
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*no_add_attrs = false; |
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return NULL_TREE; |
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} |
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|
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/* |
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* set on types that we've performed a shuffle on, to prevent re-shuffling |
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* this does not preclude us from inspecting its fields for potential shuffles |
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*/ |
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static tree handle_randomize_performed_attr(tree *node, tree name, tree args, int flags, bool *no_add_attrs) |
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{ |
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*no_add_attrs = false; |
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return NULL_TREE; |
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} |
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/* |
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* 64bit variant of Bob Jenkins' public domain PRNG |
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* 256 bits of internal state |
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*/ |
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typedef unsigned long long u64; |
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typedef struct ranctx { u64 a; u64 b; u64 c; u64 d; } ranctx; |
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#define rot(x,k) (((x)<<(k))|((x)>>(64-(k)))) |
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static u64 ranval(ranctx *x) { |
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u64 e = x->a - rot(x->b, 7); |
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x->a = x->b ^ rot(x->c, 13); |
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x->b = x->c + rot(x->d, 37); |
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x->c = x->d + e; |
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x->d = e + x->a; |
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return x->d; |
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} |
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static void raninit(ranctx *x, u64 *seed) { |
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int i; |
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x->a = seed[0]; |
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x->b = seed[1]; |
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x->c = seed[2]; |
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x->d = seed[3]; |
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for (i=0; i < 30; ++i) |
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(void)ranval(x); |
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} |
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static u64 shuffle_seed[4]; |
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struct partition_group { |
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tree tree_start; |
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unsigned long start; |
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unsigned long length; |
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}; |
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static void partition_struct(tree *fields, unsigned long length, struct partition_group *size_groups, unsigned long *num_groups) |
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{ |
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unsigned long i; |
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unsigned long accum_size = 0; |
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unsigned long accum_length = 0; |
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unsigned long group_idx = 0; |
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gcc_assert(length < INT_MAX); |
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memset(size_groups, 0, sizeof(struct partition_group) * length); |
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for (i = 0; i < length; i++) { |
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if (size_groups[group_idx].tree_start == NULL_TREE) { |
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size_groups[group_idx].tree_start = fields[i]; |
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size_groups[group_idx].start = i; |
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accum_length = 0; |
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accum_size = 0; |
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} |
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accum_size += (unsigned long)int_size_in_bytes(TREE_TYPE(fields[i])); |
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accum_length++; |
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if (accum_size >= 64) { |
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size_groups[group_idx].length = accum_length; |
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accum_length = 0; |
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group_idx++; |
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} |
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} |
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if (size_groups[group_idx].tree_start != NULL_TREE && |
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!size_groups[group_idx].length) { |
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size_groups[group_idx].length = accum_length; |
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group_idx++; |
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} |
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*num_groups = group_idx; |
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} |
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static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prng_state) |
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{ |
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unsigned long i, x; |
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struct partition_group size_group[length]; |
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unsigned long num_groups = 0; |
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unsigned long randnum; |
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partition_struct(newtree, length, (struct partition_group *)&size_group, &num_groups); |
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for (i = num_groups - 1; i > 0; i--) { |
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struct partition_group tmp; |
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randnum = ranval(prng_state) % (i + 1); |
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tmp = size_group[i]; |
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size_group[i] = size_group[randnum]; |
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size_group[randnum] = tmp; |
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} |
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for (x = 0; x < num_groups; x++) { |
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for (i = size_group[x].start + size_group[x].length - 1; i > size_group[x].start; i--) { |
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tree tmp; |
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if (DECL_BIT_FIELD_TYPE(newtree[i])) |
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continue; |
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randnum = ranval(prng_state) % (i + 1); |
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// we could handle this case differently if desired |
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if (DECL_BIT_FIELD_TYPE(newtree[randnum])) |
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continue; |
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tmp = newtree[i]; |
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newtree[i] = newtree[randnum]; |
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newtree[randnum] = tmp; |
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} |
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} |
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} |
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static void full_shuffle(tree *newtree, unsigned long length, ranctx *prng_state) |
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{ |
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unsigned long i, randnum; |
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for (i = length - 1; i > 0; i--) { |
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tree tmp; |
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randnum = ranval(prng_state) % (i + 1); |
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tmp = newtree[i]; |
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newtree[i] = newtree[randnum]; |
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newtree[randnum] = tmp; |
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} |
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} |
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/* modern in-place Fisher-Yates shuffle */ |
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static void shuffle(const_tree type, tree *newtree, unsigned long length) |
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{ |
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unsigned long i; |
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u64 seed[4]; |
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ranctx prng_state; |
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const unsigned char *structname; |
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if (length == 0) |
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return; |
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gcc_assert(TREE_CODE(type) == RECORD_TYPE); |
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structname = ORIG_TYPE_NAME(type); |
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#ifdef __DEBUG_PLUGIN |
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fprintf(stderr, "Shuffling struct %s %p\n", (const char *)structname, type); |
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#ifdef __DEBUG_VERBOSE |
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debug_tree((tree)type); |
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#endif |
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#endif |
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for (i = 0; i < 4; i++) { |
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seed[i] = shuffle_seed[i]; |
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seed[i] ^= name_hash(structname); |
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} |
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raninit(&prng_state, (u64 *)&seed); |
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if (performance_mode) |
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performance_shuffle(newtree, length, &prng_state); |
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else |
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full_shuffle(newtree, length, &prng_state); |
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} |
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static bool is_flexible_array(const_tree field) |
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{ |
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const_tree fieldtype; |
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const_tree typesize; |
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const_tree elemtype; |
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const_tree elemsize; |
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fieldtype = TREE_TYPE(field); |
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typesize = TYPE_SIZE(fieldtype); |
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if (TREE_CODE(fieldtype) != ARRAY_TYPE) |
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return false; |
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elemtype = TREE_TYPE(fieldtype); |
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elemsize = TYPE_SIZE(elemtype); |
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/* size of type is represented in bits */ |
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if (typesize == NULL_TREE && TYPE_DOMAIN(fieldtype) != NULL_TREE && |
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TYPE_MAX_VALUE(TYPE_DOMAIN(fieldtype)) == NULL_TREE) |
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return true; |
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if (typesize != NULL_TREE && |
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(TREE_CONSTANT(typesize) && (!tree_to_uhwi(typesize) || |
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tree_to_uhwi(typesize) == tree_to_uhwi(elemsize)))) |
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return true; |
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return false; |
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} |
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static int relayout_struct(tree type) |
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{ |
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unsigned long num_fields = (unsigned long)list_length(TYPE_FIELDS(type)); |
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unsigned long shuffle_length = num_fields; |
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tree field; |
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tree newtree[num_fields]; |
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unsigned long i; |
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tree list; |
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tree variant; |
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tree main_variant; |
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expanded_location xloc; |
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bool has_flexarray = false; |
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if (TYPE_FIELDS(type) == NULL_TREE) |
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return 0; |
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if (num_fields < 2) |
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return 0; |
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gcc_assert(TREE_CODE(type) == RECORD_TYPE); |
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gcc_assert(num_fields < INT_MAX); |
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if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(type)) || |
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lookup_attribute("no_randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type)))) |
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return 0; |
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/* Workaround for 3rd-party VirtualBox source that we can't modify ourselves */ |
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if (!strcmp((const char *)ORIG_TYPE_NAME(type), "INTNETTRUNKFACTORY") || |
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!strcmp((const char *)ORIG_TYPE_NAME(type), "RAWPCIFACTORY")) |
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return 0; |
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/* throw out any structs in uapi */ |
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xloc = expand_location(DECL_SOURCE_LOCATION(TYPE_FIELDS(type))); |
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if (strstr(xloc.file, "/uapi/")) |
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error(G_("attempted to randomize userland API struct %s"), ORIG_TYPE_NAME(type)); |
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for (field = TYPE_FIELDS(type), i = 0; field; field = TREE_CHAIN(field), i++) { |
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gcc_assert(TREE_CODE(field) == FIELD_DECL); |
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newtree[i] = field; |
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} |
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/* |
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* enforce that we don't randomize the layout of the last |
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* element of a struct if it's a 0 or 1-length array |
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* or a proper flexible array |
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*/ |
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if (is_flexible_array(newtree[num_fields - 1])) { |
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has_flexarray = true; |
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shuffle_length--; |
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} |
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shuffle(type, (tree *)newtree, shuffle_length); |
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/* |
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* set up a bogus anonymous struct field designed to error out on unnamed struct initializers |
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* as gcc provides no other way to detect such code |
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*/ |
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list = make_node(FIELD_DECL); |
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TREE_CHAIN(list) = newtree[0]; |
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TREE_TYPE(list) = void_type_node; |
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DECL_SIZE(list) = bitsize_zero_node; |
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DECL_NONADDRESSABLE_P(list) = 1; |
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DECL_FIELD_BIT_OFFSET(list) = bitsize_zero_node; |
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DECL_SIZE_UNIT(list) = size_zero_node; |
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DECL_FIELD_OFFSET(list) = size_zero_node; |
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DECL_CONTEXT(list) = type; |
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// to satisfy the constify plugin |
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TREE_READONLY(list) = 1; |
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for (i = 0; i < num_fields - 1; i++) |
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TREE_CHAIN(newtree[i]) = newtree[i+1]; |
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TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE; |
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main_variant = TYPE_MAIN_VARIANT(type); |
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for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) { |
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TYPE_FIELDS(variant) = list; |
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TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant)); |
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TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant)); |
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TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), NULL_TREE, TYPE_ATTRIBUTES(variant)); |
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if (has_flexarray) |
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TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("has_flexarray"), NULL_TREE, TYPE_ATTRIBUTES(type)); |
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} |
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/* |
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* force a re-layout of the main variant |
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* the TYPE_SIZE for all variants will be recomputed |
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* by finalize_type_size() |
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*/ |
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TYPE_SIZE(main_variant) = NULL_TREE; |
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layout_type(main_variant); |
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gcc_assert(TYPE_SIZE(main_variant) != NULL_TREE); |
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return 1; |
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} |
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/* from constify plugin */ |
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static const_tree get_field_type(const_tree field) |
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{ |
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return strip_array_types(TREE_TYPE(field)); |
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} |
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/* from constify plugin */ |
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static bool is_fptr(const_tree fieldtype) |
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{ |
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if (TREE_CODE(fieldtype) != POINTER_TYPE) |
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return false; |
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return TREE_CODE(TREE_TYPE(fieldtype)) == FUNCTION_TYPE; |
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} |
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/* derived from constify plugin */ |
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static int is_pure_ops_struct(const_tree node) |
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{ |
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const_tree field; |
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gcc_assert(TREE_CODE(node) == RECORD_TYPE || TREE_CODE(node) == UNION_TYPE); |
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for (field = TYPE_FIELDS(node); field; field = TREE_CHAIN(field)) { |
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const_tree fieldtype = get_field_type(field); |
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enum tree_code code = TREE_CODE(fieldtype); |
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if (node == fieldtype) |
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continue; |
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if (code == RECORD_TYPE || code == UNION_TYPE) { |
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if (!is_pure_ops_struct(fieldtype)) |
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return 0; |
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continue; |
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} |
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if (!is_fptr(fieldtype)) |
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return 0; |
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} |
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return 1; |
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} |
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static void randomize_type(tree type) |
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{ |
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tree variant; |
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gcc_assert(TREE_CODE(type) == RECORD_TYPE); |
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if (lookup_attribute("randomize_considered", TYPE_ATTRIBUTES(type))) |
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return; |
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if (lookup_attribute("randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type))) || is_pure_ops_struct(type)) |
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relayout_struct(type); |
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for (variant = TYPE_MAIN_VARIANT(type); variant; variant = TYPE_NEXT_VARIANT(variant)) { |
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TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type)); |
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TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("randomize_considered"), NULL_TREE, TYPE_ATTRIBUTES(type)); |
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} |
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#ifdef __DEBUG_PLUGIN |
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fprintf(stderr, "Marking randomize_considered on struct %s\n", ORIG_TYPE_NAME(type)); |
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#ifdef __DEBUG_VERBOSE |
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debug_tree(type); |
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#endif |
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#endif |
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} |
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static void update_decl_size(tree decl) |
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{ |
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tree lastval, lastidx, field, init, type, flexsize; |
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unsigned HOST_WIDE_INT len; |
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type = TREE_TYPE(decl); |
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if (!lookup_attribute("has_flexarray", TYPE_ATTRIBUTES(type))) |
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return; |
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init = DECL_INITIAL(decl); |
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if (init == NULL_TREE || init == error_mark_node) |
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return; |
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if (TREE_CODE(init) != CONSTRUCTOR) |
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return; |
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len = CONSTRUCTOR_NELTS(init); |
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if (!len) |
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return; |
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lastval = CONSTRUCTOR_ELT(init, CONSTRUCTOR_NELTS(init) - 1)->value; |
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lastidx = CONSTRUCTOR_ELT(init, CONSTRUCTOR_NELTS(init) - 1)->index; |
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for (field = TYPE_FIELDS(TREE_TYPE(decl)); TREE_CHAIN(field); field = TREE_CHAIN(field)) |
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; |
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if (lastidx != field) |
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return; |
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if (TREE_CODE(lastval) != STRING_CST) { |
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error("Only string constants are supported as initializers " |
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"for randomized structures with flexible arrays"); |
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return; |
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} |
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flexsize = bitsize_int(TREE_STRING_LENGTH(lastval) * |
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tree_to_uhwi(TYPE_SIZE(TREE_TYPE(TREE_TYPE(lastval))))); |
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DECL_SIZE(decl) = size_binop(PLUS_EXPR, TYPE_SIZE(type), flexsize); |
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return; |
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} |
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static void randomize_layout_finish_decl(void *event_data, void *data) |
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{ |
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tree decl = (tree)event_data; |
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tree type; |
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if (decl == NULL_TREE || decl == error_mark_node) |
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return; |
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type = TREE_TYPE(decl); |
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if (TREE_CODE(decl) != VAR_DECL) |
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return; |
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if (TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE) |
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return; |
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if (!lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(type))) |
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return; |
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DECL_SIZE(decl) = 0; |
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DECL_SIZE_UNIT(decl) = 0; |
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SET_DECL_ALIGN(decl, 0); |
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SET_DECL_MODE (decl, VOIDmode); |
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SET_DECL_RTL(decl, 0); |
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update_decl_size(decl); |
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layout_decl(decl, 0); |
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} |
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static void finish_type(void *event_data, void *data) |
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{ |
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tree type = (tree)event_data; |
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if (type == NULL_TREE || type == error_mark_node) |
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return; |
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if (TREE_CODE(type) != RECORD_TYPE) |
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return; |
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if (TYPE_FIELDS(type) == NULL_TREE) |
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return; |
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if (lookup_attribute("randomize_considered", TYPE_ATTRIBUTES(type))) |
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return; |
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#ifdef __DEBUG_PLUGIN |
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fprintf(stderr, "Calling randomize_type on %s\n", ORIG_TYPE_NAME(type)); |
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#endif |
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#ifdef __DEBUG_VERBOSE |
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debug_tree(type); |
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#endif |
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randomize_type(type); |
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|
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return; |
|
} |
|
|
|
static struct attribute_spec randomize_layout_attr = { }; |
|
static struct attribute_spec no_randomize_layout_attr = { }; |
|
static struct attribute_spec randomize_considered_attr = { }; |
|
static struct attribute_spec randomize_performed_attr = { }; |
|
|
|
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; |
|
randomize_layout_attr.affects_type_identity = true; |
|
|
|
no_randomize_layout_attr.name = "no_randomize_layout"; |
|
no_randomize_layout_attr.type_required = true; |
|
no_randomize_layout_attr.handler = handle_randomize_layout_attr; |
|
no_randomize_layout_attr.affects_type_identity = true; |
|
|
|
randomize_considered_attr.name = "randomize_considered"; |
|
randomize_considered_attr.type_required = true; |
|
randomize_considered_attr.handler = handle_randomize_considered_attr; |
|
|
|
randomize_performed_attr.name = "randomize_performed"; |
|
randomize_performed_attr.type_required = true; |
|
randomize_performed_attr.handler = handle_randomize_performed_attr; |
|
|
|
register_attribute(&randomize_layout_attr); |
|
register_attribute(&no_randomize_layout_attr); |
|
register_attribute(&randomize_considered_attr); |
|
register_attribute(&randomize_performed_attr); |
|
} |
|
|
|
static void check_bad_casts_in_constructor(tree var, tree init) |
|
{ |
|
unsigned HOST_WIDE_INT idx; |
|
tree field, val; |
|
tree field_type, val_type; |
|
|
|
FOR_EACH_CONSTRUCTOR_ELT(CONSTRUCTOR_ELTS(init), idx, field, val) { |
|
if (TREE_CODE(val) == CONSTRUCTOR) { |
|
check_bad_casts_in_constructor(var, val); |
|
continue; |
|
} |
|
|
|
/* pipacs' plugin creates franken-arrays that differ from those produced by |
|
normal code which all have valid 'field' trees. work around this */ |
|
if (field == NULL_TREE) |
|
continue; |
|
field_type = TREE_TYPE(field); |
|
val_type = TREE_TYPE(val); |
|
|
|
if (TREE_CODE(field_type) != POINTER_TYPE || TREE_CODE(val_type) != POINTER_TYPE) |
|
continue; |
|
|
|
if (field_type == val_type) |
|
continue; |
|
|
|
field_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(field_type)))); |
|
val_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(val_type)))); |
|
|
|
if (field_type == void_type_node) |
|
continue; |
|
if (field_type == val_type) |
|
continue; |
|
if (TREE_CODE(val_type) != RECORD_TYPE) |
|
continue; |
|
|
|
if (!lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(val_type))) |
|
continue; |
|
MISMATCH(DECL_SOURCE_LOCATION(var), "constructor\n", TYPE_MAIN_VARIANT(field_type), TYPE_MAIN_VARIANT(val_type)); |
|
} |
|
} |
|
|
|
/* derived from the constify plugin */ |
|
static void check_global_variables(void *event_data, void *data) |
|
{ |
|
struct varpool_node *node; |
|
tree init; |
|
|
|
FOR_EACH_VARIABLE(node) { |
|
tree var = NODE_DECL(node); |
|
init = DECL_INITIAL(var); |
|
if (init == NULL_TREE) |
|
continue; |
|
|
|
if (TREE_CODE(init) != CONSTRUCTOR) |
|
continue; |
|
|
|
check_bad_casts_in_constructor(var, init); |
|
} |
|
} |
|
|
|
static bool dominated_by_is_err(const_tree rhs, basic_block bb) |
|
{ |
|
basic_block dom; |
|
gimple dom_stmt; |
|
gimple call_stmt; |
|
const_tree dom_lhs; |
|
const_tree poss_is_err_cond; |
|
const_tree poss_is_err_func; |
|
const_tree is_err_arg; |
|
|
|
dom = get_immediate_dominator(CDI_DOMINATORS, bb); |
|
if (!dom) |
|
return false; |
|
|
|
dom_stmt = last_stmt(dom); |
|
if (!dom_stmt) |
|
return false; |
|
|
|
if (gimple_code(dom_stmt) != GIMPLE_COND) |
|
return false; |
|
|
|
if (gimple_cond_code(dom_stmt) != NE_EXPR) |
|
return false; |
|
|
|
if (!integer_zerop(gimple_cond_rhs(dom_stmt))) |
|
return false; |
|
|
|
poss_is_err_cond = gimple_cond_lhs(dom_stmt); |
|
|
|
if (TREE_CODE(poss_is_err_cond) != SSA_NAME) |
|
return false; |
|
|
|
call_stmt = SSA_NAME_DEF_STMT(poss_is_err_cond); |
|
|
|
if (gimple_code(call_stmt) != GIMPLE_CALL) |
|
return false; |
|
|
|
dom_lhs = gimple_get_lhs(call_stmt); |
|
poss_is_err_func = gimple_call_fndecl(call_stmt); |
|
if (!poss_is_err_func) |
|
return false; |
|
if (dom_lhs != poss_is_err_cond) |
|
return false; |
|
if (strcmp(DECL_NAME_POINTER(poss_is_err_func), "IS_ERR")) |
|
return false; |
|
|
|
is_err_arg = gimple_call_arg(call_stmt, 0); |
|
if (!is_err_arg) |
|
return false; |
|
|
|
if (is_err_arg != rhs) |
|
return false; |
|
|
|
return true; |
|
} |
|
|
|
static void handle_local_var_initializers(void) |
|
{ |
|
tree var; |
|
unsigned int i; |
|
|
|
FOR_EACH_LOCAL_DECL(cfun, i, var) { |
|
tree init = DECL_INITIAL(var); |
|
if (!init) |
|
continue; |
|
if (TREE_CODE(init) != CONSTRUCTOR) |
|
continue; |
|
check_bad_casts_in_constructor(var, init); |
|
} |
|
} |
|
|
|
/* |
|
* iterate over all statements to find "bad" casts: |
|
* those where the address of the start of a structure is cast |
|
* to a pointer of a structure of a different type, or a |
|
* structure pointer type is cast to a different structure pointer type |
|
*/ |
|
static unsigned int find_bad_casts_execute(void) |
|
{ |
|
basic_block bb; |
|
|
|
handle_local_var_initializers(); |
|
|
|
FOR_EACH_BB_FN(bb, cfun) { |
|
gimple_stmt_iterator gsi; |
|
|
|
for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) { |
|
gimple stmt; |
|
const_tree lhs; |
|
const_tree lhs_type; |
|
const_tree rhs1; |
|
const_tree rhs_type; |
|
const_tree ptr_lhs_type; |
|
const_tree ptr_rhs_type; |
|
const_tree op0; |
|
const_tree op0_type; |
|
enum tree_code rhs_code; |
|
|
|
stmt = gsi_stmt(gsi); |
|
|
|
#ifdef __DEBUG_PLUGIN |
|
#ifdef __DEBUG_VERBOSE |
|
debug_gimple_stmt(stmt); |
|
debug_tree(gimple_get_lhs(stmt)); |
|
#endif |
|
#endif |
|
|
|
if (gimple_code(stmt) != GIMPLE_ASSIGN) |
|
continue; |
|
|
|
#ifdef __DEBUG_PLUGIN |
|
#ifdef __DEBUG_VERBOSE |
|
debug_tree(gimple_assign_rhs1(stmt)); |
|
#endif |
|
#endif |
|
|
|
|
|
rhs_code = gimple_assign_rhs_code(stmt); |
|
|
|
if (rhs_code != ADDR_EXPR && rhs_code != SSA_NAME) |
|
continue; |
|
|
|
lhs = gimple_get_lhs(stmt); |
|
lhs_type = TREE_TYPE(lhs); |
|
rhs1 = gimple_assign_rhs1(stmt); |
|
rhs_type = TREE_TYPE(rhs1); |
|
|
|
if (TREE_CODE(rhs_type) != POINTER_TYPE || |
|
TREE_CODE(lhs_type) != POINTER_TYPE) |
|
continue; |
|
|
|
ptr_lhs_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(lhs_type)))); |
|
ptr_rhs_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(rhs_type)))); |
|
|
|
if (ptr_rhs_type == void_type_node) |
|
continue; |
|
|
|
if (ptr_lhs_type == void_type_node) |
|
continue; |
|
|
|
if (dominated_by_is_err(rhs1, bb)) |
|
continue; |
|
|
|
if (TREE_CODE(ptr_rhs_type) != RECORD_TYPE) { |
|
#ifndef __DEBUG_PLUGIN |
|
if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_lhs_type))) |
|
#endif |
|
MISMATCH(gimple_location(stmt), "rhs", ptr_lhs_type, ptr_rhs_type); |
|
continue; |
|
} |
|
|
|
if (rhs_code == SSA_NAME && ptr_lhs_type == ptr_rhs_type) |
|
continue; |
|
|
|
if (rhs_code == ADDR_EXPR) { |
|
op0 = TREE_OPERAND(rhs1, 0); |
|
|
|
if (op0 == NULL_TREE) |
|
continue; |
|
|
|
if (TREE_CODE(op0) != VAR_DECL) |
|
continue; |
|
|
|
op0_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(op0)))); |
|
if (op0_type == ptr_lhs_type) |
|
continue; |
|
|
|
#ifndef __DEBUG_PLUGIN |
|
if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(op0_type))) |
|
#endif |
|
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 */ |
|
if (ssa_name_var != NULL_TREE && DECL_NAME(ssa_name_var) && |
|
!strcmp((const char *)DECL_NAME_POINTER(ssa_name_var), "__mptr")) |
|
continue; |
|
#ifndef __DEBUG_PLUGIN |
|
if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_rhs_type))) |
|
#endif |
|
MISMATCH(gimple_location(stmt), "ssa", ptr_lhs_type, ptr_rhs_type); |
|
} |
|
|
|
} |
|
} |
|
return 0; |
|
} |
|
|
|
#define PASS_NAME find_bad_casts |
|
#define NO_GATE |
|
#define TODO_FLAGS_FINISH TODO_dump_func |
|
#include "gcc-generate-gimple-pass.h" |
|
|
|
__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) |
|
{ |
|
int i; |
|
const char * const plugin_name = plugin_info->base_name; |
|
const int argc = plugin_info->argc; |
|
const struct plugin_argument * const argv = plugin_info->argv; |
|
bool enable = true; |
|
int obtained_seed = 0; |
|
struct register_pass_info find_bad_casts_pass_info; |
|
|
|
find_bad_casts_pass_info.pass = make_find_bad_casts_pass(); |
|
find_bad_casts_pass_info.reference_pass_name = "ssa"; |
|
find_bad_casts_pass_info.ref_pass_instance_number = 1; |
|
find_bad_casts_pass_info.pos_op = PASS_POS_INSERT_AFTER; |
|
|
|
if (!plugin_default_version_check(version, &gcc_version)) { |
|
error(G_("incompatible gcc/plugin versions")); |
|
return 1; |
|
} |
|
|
|
if (strncmp(lang_hooks.name, "GNU C", 5) && !strncmp(lang_hooks.name, "GNU C+", 6)) { |
|
inform(UNKNOWN_LOCATION, G_("%s supports C only, not %s"), plugin_name, lang_hooks.name); |
|
enable = false; |
|
} |
|
|
|
for (i = 0; i < argc; ++i) { |
|
if (!strcmp(argv[i].key, "disable")) { |
|
enable = false; |
|
continue; |
|
} |
|
if (!strcmp(argv[i].key, "performance-mode")) { |
|
performance_mode = 1; |
|
continue; |
|
} |
|
error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); |
|
} |
|
|
|
if (strlen(randstruct_seed) != 64) { |
|
error(G_("invalid seed value supplied for %s plugin"), plugin_name); |
|
return 1; |
|
} |
|
obtained_seed = sscanf(randstruct_seed, "%016llx%016llx%016llx%016llx", |
|
&shuffle_seed[0], &shuffle_seed[1], &shuffle_seed[2], &shuffle_seed[3]); |
|
if (obtained_seed != 4) { |
|
error(G_("Invalid seed supplied for %s plugin"), plugin_name); |
|
return 1; |
|
} |
|
|
|
register_callback(plugin_name, PLUGIN_INFO, NULL, &randomize_layout_plugin_info); |
|
if (enable) { |
|
register_callback(plugin_name, PLUGIN_ALL_IPA_PASSES_START, check_global_variables, NULL); |
|
register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &find_bad_casts_pass_info); |
|
register_callback(plugin_name, PLUGIN_FINISH_TYPE, finish_type, NULL); |
|
register_callback(plugin_name, PLUGIN_FINISH_DECL, randomize_layout_finish_decl, NULL); |
|
} |
|
register_callback(plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL); |
|
|
|
return 0; |
|
}
|
|
|