Message ID | 20121017111131.GU584@tucnak.redhat.com |
---|---|
State | New |
Headers | show |
Yes, I think it is good for the branch. thanks, David On Wed, Oct 17, 2012 at 4:11 AM, Jakub Jelinek <jakub@redhat.com> wrote: > On Tue, Oct 16, 2012 at 02:41:42PM -0700, Xinliang David Li wrote: >> On Tue, Oct 16, 2012 at 7:58 AM, Jakub Jelinek <jakub@redhat.com> wrote: >> Why the above two condition? If the linker picks the larger size one, >> it is ok to do the instrumentation. > > Added more comments, creation of local aliases when needed, and construction > of global var description strings. > Again, only very lightly tested. > > __has_dynamic_init is still always 0, setting it to non-zero would require > dynamic initialization order support, which I'll happily leave to others. > > And the addresses are still absolute (i.e. the global vars descriptor is > still likely .data.relro.local section for -fpic), both the __beg and > __name fields, but changing it would require first libasan changes. > > Ok for asan? > > 2012-10-17 Jakub Jelinek <jakub@redhat.com> > > * varasm.c: Include asan.h. > (assemble_noswitch_variable): Grow size by asan_red_zone_size > if decl is asan protected. > (place_block_symbol): Likewise. > (assemble_variable): If decl is asan protected, increase > DECL_ALIGN if needed, and for decls emitted using > assemble_variable_contents append padding zeros after it. > * Makefile.in (varasm.o): Depend on asan.h. > * asan.c: Include output.h. > (asan_pp, asan_pp_initialized): New variables. > (asan_pp_initialize, asan_pp_string): New functions. > (asan_emit_stack_protection): Use asan_pp{,_initialized} > instead of local pp{,_initialized} vars, use asan_pp_initialize > and asan_pp_string helpers. > (asan_needs_local_alias, asan_protect_global, > asan_global_struct, asan_add_global): New functions. > (asan_finish_file): Protect global vars that can be protected. > * asan.h (asan_protect_global): New prototype. > (asan_red_zone_size): New inline function. > > --- gcc/varasm.c.jj 2012-10-11 19:10:39.000000000 +0200 > +++ gcc/varasm.c 2012-10-16 15:40:37.075662625 +0200 > @@ -51,6 +51,7 @@ along with GCC; see the file COPYING3. > #include "tree-mudflap.h" > #include "cgraph.h" > #include "pointer-set.h" > +#include "asan.h" > > #ifdef XCOFF_DEBUGGING_INFO > #include "xcoffout.h" /* Needed for external data > @@ -1831,6 +1832,9 @@ assemble_noswitch_variable (tree decl, c > size = tree_low_cst (DECL_SIZE_UNIT (decl), 1); > rounded = size; > > + if (flag_asan && asan_protect_global (decl)) > + size += asan_red_zone_size (size); > + > /* Don't allocate zero bytes of common, > since that means "undefined external" in the linker. */ > if (size == 0) > @@ -1897,6 +1901,7 @@ assemble_variable (tree decl, int top_le > const char *name; > rtx decl_rtl, symbol; > section *sect; > + bool asan_protected = false; > > /* This function is supposed to handle VARIABLES. Ensure we have one. */ > gcc_assert (TREE_CODE (decl) == VAR_DECL); > @@ -1984,6 +1989,15 @@ assemble_variable (tree decl, int top_le > /* Compute the alignment of this data. */ > > align_variable (decl, dont_output_data); > + > + if (flag_asan > + && asan_protect_global (decl) > + && DECL_ALIGN (decl) < ASAN_RED_ZONE_SIZE * BITS_PER_UNIT) > + { > + asan_protected = true; > + DECL_ALIGN (decl) = ASAN_RED_ZONE_SIZE * BITS_PER_UNIT; > + } > + > set_mem_align (decl_rtl, DECL_ALIGN (decl)); > > if (TREE_PUBLIC (decl)) > @@ -2022,6 +2036,12 @@ assemble_variable (tree decl, int top_le > if (DECL_ALIGN (decl) > BITS_PER_UNIT) > ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (DECL_ALIGN_UNIT (decl))); > assemble_variable_contents (decl, name, dont_output_data); > + if (asan_protected) > + { > + unsigned HOST_WIDE_INT int size > + = tree_low_cst (DECL_SIZE_UNIT (decl), 1); > + assemble_zeros (asan_red_zone_size (size)); > + } > } > } > > @@ -6926,6 +6946,8 @@ place_block_symbol (rtx symbol) > decl = SYMBOL_REF_DECL (symbol); > alignment = DECL_ALIGN (decl); > size = tree_low_cst (DECL_SIZE_UNIT (decl), 1); > + if (flag_asan && asan_protect_global (decl)) > + size += asan_red_zone_size (size); > } > > /* Calculate the object's offset from the start of the block. */ > --- gcc/Makefile.in.jj 2012-10-15 09:40:40.000000000 +0200 > +++ gcc/Makefile.in 2012-10-17 13:00:02.995133686 +0200 > @@ -2712,7 +2712,7 @@ varasm.o : varasm.c $(CONFIG_H) $(SYSTEM > output.h $(DIAGNOSTIC_CORE_H) xcoffout.h debug.h $(GGC_H) $(TM_P_H) \ > $(HASHTAB_H) $(TARGET_H) langhooks.h gt-varasm.h $(BASIC_BLOCK_H) \ > $(CGRAPH_H) $(TARGET_DEF_H) tree-mudflap.h \ > - pointer-set.h $(COMMON_TARGET_H) > + pointer-set.h $(COMMON_TARGET_H) asan.h > function.o : function.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_ERROR_H) \ > $(TREE_H) $(GIMPLE_H) $(FLAGS_H) $(FUNCTION_H) $(EXPR_H) \ > $(OPTABS_H) $(LIBFUNCS_H) $(REGS_H) hard-reg-set.h insn-config.h $(RECOG_H) \ > --- gcc/asan.c.jj 2012-10-16 12:18:41.000000000 +0200 > +++ gcc/asan.c 2012-10-17 12:59:45.663228828 +0200 > @@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. > #include "target.h" > #include "expr.h" > #include "optabs.h" > +#include "output.h" > > /* > AddressSanitizer finds out-of-bounds and use-after-free bugs > @@ -87,6 +88,34 @@ alias_set_type asan_shadow_set = -1; > alias set is used for all shadow memory accesses. */ > static GTY(()) tree shadow_ptr_types[2]; > > +/* Asan pretty-printer, used for buidling of the description STRING_CSTs. */ > +static pretty_printer asan_pp; > +static bool asan_pp_initialized; > + > +/* Initialize asan_pp. */ > + > +static void > +asan_pp_initialize (void) > +{ > + pp_construct (&asan_pp, /* prefix */NULL, /* line-width */0); > + asan_pp_initialized = true; > +} > + > +/* Create ADDR_EXPR of STRING_CST with asan_pp text. */ > + > +static tree > +asan_pp_string (void) > +{ > + const char *buf = pp_base_formatted_text (&asan_pp); > + size_t len = strlen (buf); > + tree ret = build_string (len + 1, buf); > + TREE_TYPE (ret) > + = build_array_type (char_type_node, build_index_type (size_int (len))); > + TREE_READONLY (ret) = 1; > + TREE_STATIC (ret) = 1; > + return build1 (ADDR_EXPR, build_pointer_type (char_type_node), ret); > +} > + > /* Return a CONST_INT representing 4 subsequent shadow memory bytes. */ > > static rtx > @@ -121,51 +150,38 @@ asan_emit_stack_protection (rtx base, HO > HOST_WIDE_INT last_offset, last_size; > int l; > unsigned char cur_shadow_byte = ASAN_STACK_MAGIC_LEFT; > - static pretty_printer pp; > - static bool pp_initialized; > - const char *buf; > - size_t len; > tree str_cst; > > /* First of all, prepare the description string. */ > - if (!pp_initialized) > - { > - pp_construct (&pp, /* prefix */NULL, /* line-width */0); > - pp_initialized = true; > - } > - pp_clear_output_area (&pp); > + if (!asan_pp_initialized) > + asan_pp_initialize (); > + > + pp_clear_output_area (&asan_pp); > if (DECL_NAME (current_function_decl)) > - pp_base_tree_identifier (&pp, DECL_NAME (current_function_decl)); > + pp_base_tree_identifier (&asan_pp, DECL_NAME (current_function_decl)); > else > - pp_string (&pp, "<unknown>"); > - pp_space (&pp); > - pp_decimal_int (&pp, length / 2 - 1); > - pp_space (&pp); > + pp_string (&asan_pp, "<unknown>"); > + pp_space (&asan_pp); > + pp_decimal_int (&asan_pp, length / 2 - 1); > + pp_space (&asan_pp); > for (l = length - 2; l; l -= 2) > { > tree decl = decls[l / 2 - 1]; > - pp_wide_integer (&pp, offsets[l] - base_offset); > - pp_space (&pp); > - pp_wide_integer (&pp, offsets[l - 1] - offsets[l]); > - pp_space (&pp); > + pp_wide_integer (&asan_pp, offsets[l] - base_offset); > + pp_space (&asan_pp); > + pp_wide_integer (&asan_pp, offsets[l - 1] - offsets[l]); > + pp_space (&asan_pp); > if (DECL_P (decl) && DECL_NAME (decl)) > { > - pp_decimal_int (&pp, IDENTIFIER_LENGTH (DECL_NAME (decl))); > - pp_space (&pp); > - pp_base_tree_identifier (&pp, DECL_NAME (decl)); > + pp_decimal_int (&asan_pp, IDENTIFIER_LENGTH (DECL_NAME (decl))); > + pp_space (&asan_pp); > + pp_base_tree_identifier (&asan_pp, DECL_NAME (decl)); > } > else > - pp_string (&pp, "9 <unknown>"); > - pp_space (&pp); > + pp_string (&asan_pp, "9 <unknown>"); > + pp_space (&asan_pp); > } > - buf = pp_base_formatted_text (&pp); > - len = strlen (buf); > - str_cst = build_string (len + 1, buf); > - TREE_TYPE (str_cst) > - = build_array_type (char_type_node, build_index_type (size_int (len))); > - TREE_READONLY (str_cst) = 1; > - TREE_STATIC (str_cst) = 1; > - str_cst = build1 (ADDR_EXPR, build_pointer_type (char_type_node), str_cst); > + str_cst = asan_pp_string (); > > /* Emit the prologue sequence. */ > base = expand_binop (Pmode, add_optab, base, GEN_INT (base_offset), > @@ -270,6 +286,75 @@ asan_emit_stack_protection (rtx base, HO > return ret; > } > > +/* Return true if DECL, a global var, might be overridden and needs > + therefore a local alias. */ > + > +static bool > +asan_needs_local_alias (tree decl) > +{ > + return DECL_WEAK (decl) || !targetm.binds_local_p (decl); > +} > + > +/* Return true if DECL is a VAR_DECL that should be protected > + by Address Sanitizer, by appending a red zone with protected > + shadow memory after it and aligning it to at least > + ASAN_RED_ZONE_SIZE bytes. */ > + > +bool > +asan_protect_global (tree decl) > +{ > + rtx rtl, symbol; > + section *sect; > + > + if (TREE_CODE (decl) != VAR_DECL > + /* TLS vars aren't statically protectable. */ > + || DECL_THREAD_LOCAL_P (decl) > + /* Externs will be protected elsewhere. */ > + || DECL_EXTERNAL (decl) > + || !TREE_ASM_WRITTEN (decl) > + || !DECL_RTL_SET_P (decl) > + /* Comdat vars pose an ABI problem, we can't know if > + the var that is selected by the linker will have > + padding or not. */ > + || DECL_ONE_ONLY (decl) > + /* Similarly for common vars. People can use -fno-common. */ > + || DECL_COMMON (decl) > + /* Don't protect if using user section, often vars placed > + into user section from multiple TUs are then assumed > + to be an array of such vars, putting padding in there > + breaks this assumption. */ > + || (DECL_SECTION_NAME (decl) != NULL_TREE > + && !DECL_HAS_IMPLICIT_SECTION_NAME_P (decl)) > + || DECL_SIZE (decl) == 0 > + || ASAN_RED_ZONE_SIZE * BITS_PER_UNIT > MAX_OFILE_ALIGNMENT > + || !valid_constant_size_p (DECL_SIZE_UNIT (decl)) > + || DECL_ALIGN_UNIT (decl) > 2 * ASAN_RED_ZONE_SIZE) > + return false; > + > + rtl = DECL_RTL (decl); > + if (!MEM_P (rtl) || GET_CODE (XEXP (rtl, 0)) != SYMBOL_REF) > + return false; > + symbol = XEXP (rtl, 0); > + > + if (CONSTANT_POOL_ADDRESS_P (symbol) > + || TREE_CONSTANT_POOL_ADDRESS_P (symbol)) > + return false; > + > + sect = get_variable_section (decl, false); > + if (sect->common.flags & SECTION_COMMON) > + return false; > + > + if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl))) > + return false; > + > +#ifndef ASM_OUTPUT_DEF > + if (asan_needs_local_alias (decl)) > + return false; > +#endif > + > + return true; > +} > + > /* Construct a function tree for __asan_report_{load,store}{1,2,4,8,16}. > IS_STORE is either 1 (for a store) or 0 (for a load). > SIZE_IN_BYTES is one of 1, 2, 4, 8, 16. */ > @@ -568,6 +653,101 @@ transform_statements (void) > } > } > > +/* Build > + struct __asan_global > + { > + const void *__beg; > + uptr __size; > + uptr __size_with_redzone; > + const void *__name; > + uptr __has_dynamic_init; > + } type. */ > + > +static tree > +asan_global_struct (void) > +{ > + static const char *field_names[5] > + = { "__beg", "__size", "__size_with_redzone", > + "__name", "__has_dynamic_init" }; > + tree fields[5], ret; > + int i; > + > + ret = make_node (RECORD_TYPE); > + for (i = 0; i < 5; i++) > + { > + fields[i] > + = build_decl (UNKNOWN_LOCATION, FIELD_DECL, > + get_identifier (field_names[i]), > + (i == 0 || i == 3) ? const_ptr_type_node > + : build_nonstandard_integer_type (POINTER_SIZE, 1)); > + DECL_CONTEXT (fields[i]) = ret; > + if (i) > + DECL_CHAIN (fields[i - 1]) = fields[i]; > + } > + TYPE_FIELDS (ret) = fields[0]; > + TYPE_NAME (ret) = get_identifier ("__asan_global"); > + layout_type (ret); > + return ret; > +} > + > +/* Append description of a single global DECL into vector V. > + TYPE is __asan_global struct type as returned by asan_global_struct. */ > + > +static void > +asan_add_global (tree decl, tree type, VEC(constructor_elt, gc) *v) > +{ > + tree init, uptr = TREE_TYPE (DECL_CHAIN (TYPE_FIELDS (type))); > + unsigned HOST_WIDE_INT size; > + tree str_cst, refdecl = decl; > + VEC(constructor_elt, gc) *vinner = NULL; > + > + if (!asan_pp_initialized) > + asan_pp_initialize (); > + > + pp_clear_output_area (&asan_pp); > + if (DECL_NAME (decl)) > + pp_base_tree_identifier (&asan_pp, DECL_NAME (decl)); > + else > + pp_string (&asan_pp, "<unknown>"); > + pp_space (&asan_pp); > + pp_left_paren (&asan_pp); > + pp_string (&asan_pp, main_input_filename); > + pp_right_paren (&asan_pp); > + str_cst = asan_pp_string (); > + > + if (asan_needs_local_alias (decl)) > + { > + char buf[20]; > + ASM_GENERATE_INTERNAL_LABEL (buf, "LASAN", > + VEC_length (constructor_elt, v) + 1); > + refdecl = build_decl (DECL_SOURCE_LOCATION (decl), > + VAR_DECL, get_identifier (buf), TREE_TYPE (decl)); > + TREE_ADDRESSABLE (refdecl) = TREE_ADDRESSABLE (decl); > + TREE_READONLY (refdecl) = TREE_READONLY (decl); > + TREE_THIS_VOLATILE (refdecl) = TREE_THIS_VOLATILE (decl); > + DECL_GIMPLE_REG_P (refdecl) = DECL_GIMPLE_REG_P (decl); > + DECL_ARTIFICIAL (refdecl) = DECL_ARTIFICIAL (decl); > + DECL_IGNORED_P (refdecl) = DECL_IGNORED_P (decl); > + TREE_STATIC (refdecl) = 1; > + TREE_PUBLIC (refdecl) = 0; > + TREE_USED (refdecl) = 1; > + assemble_alias (refdecl, DECL_ASSEMBLER_NAME (decl)); > + } > + > + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, > + fold_convert (const_ptr_type_node, > + build_fold_addr_expr (refdecl))); > + size = tree_low_cst (DECL_SIZE_UNIT (decl), 1); > + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, build_int_cst (uptr, size)); > + size += asan_red_zone_size (size); > + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, build_int_cst (uptr, size)); > + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, > + fold_convert (const_ptr_type_node, str_cst)); > + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, build_int_cst (uptr, 0)); > + init = build_constructor (type, vinner); > + CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init); > +} > + > /* Module-level instrumentation. > - Insert __asan_init() into the list of CTORs. > - TODO: insert redzones around globals. > @@ -577,10 +757,61 @@ void > asan_finish_file (void) > { > tree ctor_statements = NULL_TREE; > + struct varpool_node *vnode; > + unsigned HOST_WIDE_INT gcount = 0; > + > append_to_statement_list (build_call_expr (asan_init_func (), 0), > - &ctor_statements); > + &ctor_statements); > + FOR_EACH_DEFINED_VARIABLE (vnode) > + if (asan_protect_global (vnode->symbol.decl)) > + ++gcount; > + if (gcount) > + { > + tree type = asan_global_struct (), var, ctor, decl; > + tree uptr = build_nonstandard_integer_type (POINTER_SIZE, 1); > + tree dtor_statements = NULL_TREE; > + VEC(constructor_elt, gc) *v; > + char buf[20]; > + > + type = build_array_type_nelts (type, gcount); > + ASM_GENERATE_INTERNAL_LABEL (buf, "LASAN", 0); > + var = build_decl (UNKNOWN_LOCATION, VAR_DECL, get_identifier (buf), > + type); > + TREE_STATIC (var) = 1; > + TREE_PUBLIC (var) = 0; > + DECL_ARTIFICIAL (var) = 1; > + DECL_IGNORED_P (var) = 1; > + v = VEC_alloc (constructor_elt, gc, gcount); > + FOR_EACH_DEFINED_VARIABLE (vnode) > + if (asan_protect_global (vnode->symbol.decl)) > + asan_add_global (vnode->symbol.decl, TREE_TYPE (type), v); > + ctor = build_constructor (type, v); > + TREE_CONSTANT (ctor) = 1; > + TREE_STATIC (ctor) = 1; > + DECL_INITIAL (var) = ctor; > + varpool_assemble_decl (varpool_node (var)); > + > + type = build_function_type_list (void_type_node, > + build_pointer_type (TREE_TYPE (type)), > + uptr, NULL_TREE); > + decl = build_fn_decl ("__asan_register_globals", type); > + TREE_NOTHROW (decl) = 1; > + append_to_statement_list (build_call_expr (decl, 2, > + build_fold_addr_expr (var), > + build_int_cst (uptr, gcount)), > + &ctor_statements); > + > + decl = build_fn_decl ("__asan_unregister_globals", type); > + TREE_NOTHROW (decl) = 1; > + append_to_statement_list (build_call_expr (decl, 2, > + build_fold_addr_expr (var), > + build_int_cst (uptr, gcount)), > + &dtor_statements); > + cgraph_build_static_cdtor ('D', dtor_statements, > + MAX_RESERVED_INIT_PRIORITY - 1); > + } > cgraph_build_static_cdtor ('I', ctor_statements, > - MAX_RESERVED_INIT_PRIORITY - 1); > + MAX_RESERVED_INIT_PRIORITY - 1); > } > > /* Initialize shadow_ptr_types array. */ > --- gcc/asan.h.jj 2012-10-17 11:01:17.720950926 +0200 > +++ gcc/asan.h 2012-10-17 11:01:05.669018002 +0200 > @@ -23,6 +23,7 @@ along with GCC; see the file COPYING3. > > extern void asan_finish_file (void); > extern rtx asan_emit_stack_protection (rtx, HOST_WIDE_INT *, tree *, int); > +extern bool asan_protect_global (tree); > > /* Alias set for accessing the shadow memory. */ > extern alias_set_type asan_shadow_set; > @@ -56,4 +57,14 @@ asan_protect_stack_decl (tree decl) > return DECL_P (decl) && !DECL_ARTIFICIAL (decl); > } > > +/* Return the size of padding needed to insert after a protected > + decl of SIZE. */ > + > +static inline unsigned int > +asan_red_zone_size (unsigned int size) > +{ > + unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1); > + return c ? 2 * ASAN_RED_ZONE_SIZE - c : ASAN_RED_ZONE_SIZE; > +} > + > #endif /* TREE_ASAN */ > > Jakub
On 2012-10-17 07:11 , Jakub Jelinek wrote: > 2012-10-17 Jakub Jelinek <jakub@redhat.com> > > * varasm.c: Include asan.h. > (assemble_noswitch_variable): Grow size by asan_red_zone_size > if decl is asan protected. > (place_block_symbol): Likewise. > (assemble_variable): If decl is asan protected, increase > DECL_ALIGN if needed, and for decls emitted using > assemble_variable_contents append padding zeros after it. > * Makefile.in (varasm.o): Depend on asan.h. > * asan.c: Include output.h. > (asan_pp, asan_pp_initialized): New variables. > (asan_pp_initialize, asan_pp_string): New functions. > (asan_emit_stack_protection): Use asan_pp{,_initialized} > instead of local pp{,_initialized} vars, use asan_pp_initialize > and asan_pp_string helpers. > (asan_needs_local_alias, asan_protect_global, > asan_global_struct, asan_add_global): New functions. > (asan_finish_file): Protect global vars that can be protected. > * asan.h (asan_protect_global): New prototype. > (asan_red_zone_size): New inline function. This is OK. Thanks. Diego.
--- gcc/varasm.c.jj 2012-10-11 19:10:39.000000000 +0200 +++ gcc/varasm.c 2012-10-16 15:40:37.075662625 +0200 @@ -51,6 +51,7 @@ along with GCC; see the file COPYING3. #include "tree-mudflap.h" #include "cgraph.h" #include "pointer-set.h" +#include "asan.h" #ifdef XCOFF_DEBUGGING_INFO #include "xcoffout.h" /* Needed for external data @@ -1831,6 +1832,9 @@ assemble_noswitch_variable (tree decl, c size = tree_low_cst (DECL_SIZE_UNIT (decl), 1); rounded = size; + if (flag_asan && asan_protect_global (decl)) + size += asan_red_zone_size (size); + /* Don't allocate zero bytes of common, since that means "undefined external" in the linker. */ if (size == 0) @@ -1897,6 +1901,7 @@ assemble_variable (tree decl, int top_le const char *name; rtx decl_rtl, symbol; section *sect; + bool asan_protected = false; /* This function is supposed to handle VARIABLES. Ensure we have one. */ gcc_assert (TREE_CODE (decl) == VAR_DECL); @@ -1984,6 +1989,15 @@ assemble_variable (tree decl, int top_le /* Compute the alignment of this data. */ align_variable (decl, dont_output_data); + + if (flag_asan + && asan_protect_global (decl) + && DECL_ALIGN (decl) < ASAN_RED_ZONE_SIZE * BITS_PER_UNIT) + { + asan_protected = true; + DECL_ALIGN (decl) = ASAN_RED_ZONE_SIZE * BITS_PER_UNIT; + } + set_mem_align (decl_rtl, DECL_ALIGN (decl)); if (TREE_PUBLIC (decl)) @@ -2022,6 +2036,12 @@ assemble_variable (tree decl, int top_le if (DECL_ALIGN (decl) > BITS_PER_UNIT) ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (DECL_ALIGN_UNIT (decl))); assemble_variable_contents (decl, name, dont_output_data); + if (asan_protected) + { + unsigned HOST_WIDE_INT int size + = tree_low_cst (DECL_SIZE_UNIT (decl), 1); + assemble_zeros (asan_red_zone_size (size)); + } } } @@ -6926,6 +6946,8 @@ place_block_symbol (rtx symbol) decl = SYMBOL_REF_DECL (symbol); alignment = DECL_ALIGN (decl); size = tree_low_cst (DECL_SIZE_UNIT (decl), 1); + if (flag_asan && asan_protect_global (decl)) + size += asan_red_zone_size (size); } /* Calculate the object's offset from the start of the block. */ --- gcc/Makefile.in.jj 2012-10-15 09:40:40.000000000 +0200 +++ gcc/Makefile.in 2012-10-17 13:00:02.995133686 +0200 @@ -2712,7 +2712,7 @@ varasm.o : varasm.c $(CONFIG_H) $(SYSTEM output.h $(DIAGNOSTIC_CORE_H) xcoffout.h debug.h $(GGC_H) $(TM_P_H) \ $(HASHTAB_H) $(TARGET_H) langhooks.h gt-varasm.h $(BASIC_BLOCK_H) \ $(CGRAPH_H) $(TARGET_DEF_H) tree-mudflap.h \ - pointer-set.h $(COMMON_TARGET_H) + pointer-set.h $(COMMON_TARGET_H) asan.h function.o : function.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_ERROR_H) \ $(TREE_H) $(GIMPLE_H) $(FLAGS_H) $(FUNCTION_H) $(EXPR_H) \ $(OPTABS_H) $(LIBFUNCS_H) $(REGS_H) hard-reg-set.h insn-config.h $(RECOG_H) \ --- gcc/asan.c.jj 2012-10-16 12:18:41.000000000 +0200 +++ gcc/asan.c 2012-10-17 12:59:45.663228828 +0200 @@ -45,6 +45,7 @@ along with GCC; see the file COPYING3. #include "target.h" #include "expr.h" #include "optabs.h" +#include "output.h" /* AddressSanitizer finds out-of-bounds and use-after-free bugs @@ -87,6 +88,34 @@ alias_set_type asan_shadow_set = -1; alias set is used for all shadow memory accesses. */ static GTY(()) tree shadow_ptr_types[2]; +/* Asan pretty-printer, used for buidling of the description STRING_CSTs. */ +static pretty_printer asan_pp; +static bool asan_pp_initialized; + +/* Initialize asan_pp. */ + +static void +asan_pp_initialize (void) +{ + pp_construct (&asan_pp, /* prefix */NULL, /* line-width */0); + asan_pp_initialized = true; +} + +/* Create ADDR_EXPR of STRING_CST with asan_pp text. */ + +static tree +asan_pp_string (void) +{ + const char *buf = pp_base_formatted_text (&asan_pp); + size_t len = strlen (buf); + tree ret = build_string (len + 1, buf); + TREE_TYPE (ret) + = build_array_type (char_type_node, build_index_type (size_int (len))); + TREE_READONLY (ret) = 1; + TREE_STATIC (ret) = 1; + return build1 (ADDR_EXPR, build_pointer_type (char_type_node), ret); +} + /* Return a CONST_INT representing 4 subsequent shadow memory bytes. */ static rtx @@ -121,51 +150,38 @@ asan_emit_stack_protection (rtx base, HO HOST_WIDE_INT last_offset, last_size; int l; unsigned char cur_shadow_byte = ASAN_STACK_MAGIC_LEFT; - static pretty_printer pp; - static bool pp_initialized; - const char *buf; - size_t len; tree str_cst; /* First of all, prepare the description string. */ - if (!pp_initialized) - { - pp_construct (&pp, /* prefix */NULL, /* line-width */0); - pp_initialized = true; - } - pp_clear_output_area (&pp); + if (!asan_pp_initialized) + asan_pp_initialize (); + + pp_clear_output_area (&asan_pp); if (DECL_NAME (current_function_decl)) - pp_base_tree_identifier (&pp, DECL_NAME (current_function_decl)); + pp_base_tree_identifier (&asan_pp, DECL_NAME (current_function_decl)); else - pp_string (&pp, "<unknown>"); - pp_space (&pp); - pp_decimal_int (&pp, length / 2 - 1); - pp_space (&pp); + pp_string (&asan_pp, "<unknown>"); + pp_space (&asan_pp); + pp_decimal_int (&asan_pp, length / 2 - 1); + pp_space (&asan_pp); for (l = length - 2; l; l -= 2) { tree decl = decls[l / 2 - 1]; - pp_wide_integer (&pp, offsets[l] - base_offset); - pp_space (&pp); - pp_wide_integer (&pp, offsets[l - 1] - offsets[l]); - pp_space (&pp); + pp_wide_integer (&asan_pp, offsets[l] - base_offset); + pp_space (&asan_pp); + pp_wide_integer (&asan_pp, offsets[l - 1] - offsets[l]); + pp_space (&asan_pp); if (DECL_P (decl) && DECL_NAME (decl)) { - pp_decimal_int (&pp, IDENTIFIER_LENGTH (DECL_NAME (decl))); - pp_space (&pp); - pp_base_tree_identifier (&pp, DECL_NAME (decl)); + pp_decimal_int (&asan_pp, IDENTIFIER_LENGTH (DECL_NAME (decl))); + pp_space (&asan_pp); + pp_base_tree_identifier (&asan_pp, DECL_NAME (decl)); } else - pp_string (&pp, "9 <unknown>"); - pp_space (&pp); + pp_string (&asan_pp, "9 <unknown>"); + pp_space (&asan_pp); } - buf = pp_base_formatted_text (&pp); - len = strlen (buf); - str_cst = build_string (len + 1, buf); - TREE_TYPE (str_cst) - = build_array_type (char_type_node, build_index_type (size_int (len))); - TREE_READONLY (str_cst) = 1; - TREE_STATIC (str_cst) = 1; - str_cst = build1 (ADDR_EXPR, build_pointer_type (char_type_node), str_cst); + str_cst = asan_pp_string (); /* Emit the prologue sequence. */ base = expand_binop (Pmode, add_optab, base, GEN_INT (base_offset), @@ -270,6 +286,75 @@ asan_emit_stack_protection (rtx base, HO return ret; } +/* Return true if DECL, a global var, might be overridden and needs + therefore a local alias. */ + +static bool +asan_needs_local_alias (tree decl) +{ + return DECL_WEAK (decl) || !targetm.binds_local_p (decl); +} + +/* Return true if DECL is a VAR_DECL that should be protected + by Address Sanitizer, by appending a red zone with protected + shadow memory after it and aligning it to at least + ASAN_RED_ZONE_SIZE bytes. */ + +bool +asan_protect_global (tree decl) +{ + rtx rtl, symbol; + section *sect; + + if (TREE_CODE (decl) != VAR_DECL + /* TLS vars aren't statically protectable. */ + || DECL_THREAD_LOCAL_P (decl) + /* Externs will be protected elsewhere. */ + || DECL_EXTERNAL (decl) + || !TREE_ASM_WRITTEN (decl) + || !DECL_RTL_SET_P (decl) + /* Comdat vars pose an ABI problem, we can't know if + the var that is selected by the linker will have + padding or not. */ + || DECL_ONE_ONLY (decl) + /* Similarly for common vars. People can use -fno-common. */ + || DECL_COMMON (decl) + /* Don't protect if using user section, often vars placed + into user section from multiple TUs are then assumed + to be an array of such vars, putting padding in there + breaks this assumption. */ + || (DECL_SECTION_NAME (decl) != NULL_TREE + && !DECL_HAS_IMPLICIT_SECTION_NAME_P (decl)) + || DECL_SIZE (decl) == 0 + || ASAN_RED_ZONE_SIZE * BITS_PER_UNIT > MAX_OFILE_ALIGNMENT + || !valid_constant_size_p (DECL_SIZE_UNIT (decl)) + || DECL_ALIGN_UNIT (decl) > 2 * ASAN_RED_ZONE_SIZE) + return false; + + rtl = DECL_RTL (decl); + if (!MEM_P (rtl) || GET_CODE (XEXP (rtl, 0)) != SYMBOL_REF) + return false; + symbol = XEXP (rtl, 0); + + if (CONSTANT_POOL_ADDRESS_P (symbol) + || TREE_CONSTANT_POOL_ADDRESS_P (symbol)) + return false; + + sect = get_variable_section (decl, false); + if (sect->common.flags & SECTION_COMMON) + return false; + + if (lookup_attribute ("weakref", DECL_ATTRIBUTES (decl))) + return false; + +#ifndef ASM_OUTPUT_DEF + if (asan_needs_local_alias (decl)) + return false; +#endif + + return true; +} + /* Construct a function tree for __asan_report_{load,store}{1,2,4,8,16}. IS_STORE is either 1 (for a store) or 0 (for a load). SIZE_IN_BYTES is one of 1, 2, 4, 8, 16. */ @@ -568,6 +653,101 @@ transform_statements (void) } } +/* Build + struct __asan_global + { + const void *__beg; + uptr __size; + uptr __size_with_redzone; + const void *__name; + uptr __has_dynamic_init; + } type. */ + +static tree +asan_global_struct (void) +{ + static const char *field_names[5] + = { "__beg", "__size", "__size_with_redzone", + "__name", "__has_dynamic_init" }; + tree fields[5], ret; + int i; + + ret = make_node (RECORD_TYPE); + for (i = 0; i < 5; i++) + { + fields[i] + = build_decl (UNKNOWN_LOCATION, FIELD_DECL, + get_identifier (field_names[i]), + (i == 0 || i == 3) ? const_ptr_type_node + : build_nonstandard_integer_type (POINTER_SIZE, 1)); + DECL_CONTEXT (fields[i]) = ret; + if (i) + DECL_CHAIN (fields[i - 1]) = fields[i]; + } + TYPE_FIELDS (ret) = fields[0]; + TYPE_NAME (ret) = get_identifier ("__asan_global"); + layout_type (ret); + return ret; +} + +/* Append description of a single global DECL into vector V. + TYPE is __asan_global struct type as returned by asan_global_struct. */ + +static void +asan_add_global (tree decl, tree type, VEC(constructor_elt, gc) *v) +{ + tree init, uptr = TREE_TYPE (DECL_CHAIN (TYPE_FIELDS (type))); + unsigned HOST_WIDE_INT size; + tree str_cst, refdecl = decl; + VEC(constructor_elt, gc) *vinner = NULL; + + if (!asan_pp_initialized) + asan_pp_initialize (); + + pp_clear_output_area (&asan_pp); + if (DECL_NAME (decl)) + pp_base_tree_identifier (&asan_pp, DECL_NAME (decl)); + else + pp_string (&asan_pp, "<unknown>"); + pp_space (&asan_pp); + pp_left_paren (&asan_pp); + pp_string (&asan_pp, main_input_filename); + pp_right_paren (&asan_pp); + str_cst = asan_pp_string (); + + if (asan_needs_local_alias (decl)) + { + char buf[20]; + ASM_GENERATE_INTERNAL_LABEL (buf, "LASAN", + VEC_length (constructor_elt, v) + 1); + refdecl = build_decl (DECL_SOURCE_LOCATION (decl), + VAR_DECL, get_identifier (buf), TREE_TYPE (decl)); + TREE_ADDRESSABLE (refdecl) = TREE_ADDRESSABLE (decl); + TREE_READONLY (refdecl) = TREE_READONLY (decl); + TREE_THIS_VOLATILE (refdecl) = TREE_THIS_VOLATILE (decl); + DECL_GIMPLE_REG_P (refdecl) = DECL_GIMPLE_REG_P (decl); + DECL_ARTIFICIAL (refdecl) = DECL_ARTIFICIAL (decl); + DECL_IGNORED_P (refdecl) = DECL_IGNORED_P (decl); + TREE_STATIC (refdecl) = 1; + TREE_PUBLIC (refdecl) = 0; + TREE_USED (refdecl) = 1; + assemble_alias (refdecl, DECL_ASSEMBLER_NAME (decl)); + } + + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, + fold_convert (const_ptr_type_node, + build_fold_addr_expr (refdecl))); + size = tree_low_cst (DECL_SIZE_UNIT (decl), 1); + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, build_int_cst (uptr, size)); + size += asan_red_zone_size (size); + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, build_int_cst (uptr, size)); + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, + fold_convert (const_ptr_type_node, str_cst)); + CONSTRUCTOR_APPEND_ELT (vinner, NULL_TREE, build_int_cst (uptr, 0)); + init = build_constructor (type, vinner); + CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, init); +} + /* Module-level instrumentation. - Insert __asan_init() into the list of CTORs. - TODO: insert redzones around globals. @@ -577,10 +757,61 @@ void asan_finish_file (void) { tree ctor_statements = NULL_TREE; + struct varpool_node *vnode; + unsigned HOST_WIDE_INT gcount = 0; + append_to_statement_list (build_call_expr (asan_init_func (), 0), - &ctor_statements); + &ctor_statements); + FOR_EACH_DEFINED_VARIABLE (vnode) + if (asan_protect_global (vnode->symbol.decl)) + ++gcount; + if (gcount) + { + tree type = asan_global_struct (), var, ctor, decl; + tree uptr = build_nonstandard_integer_type (POINTER_SIZE, 1); + tree dtor_statements = NULL_TREE; + VEC(constructor_elt, gc) *v; + char buf[20]; + + type = build_array_type_nelts (type, gcount); + ASM_GENERATE_INTERNAL_LABEL (buf, "LASAN", 0); + var = build_decl (UNKNOWN_LOCATION, VAR_DECL, get_identifier (buf), + type); + TREE_STATIC (var) = 1; + TREE_PUBLIC (var) = 0; + DECL_ARTIFICIAL (var) = 1; + DECL_IGNORED_P (var) = 1; + v = VEC_alloc (constructor_elt, gc, gcount); + FOR_EACH_DEFINED_VARIABLE (vnode) + if (asan_protect_global (vnode->symbol.decl)) + asan_add_global (vnode->symbol.decl, TREE_TYPE (type), v); + ctor = build_constructor (type, v); + TREE_CONSTANT (ctor) = 1; + TREE_STATIC (ctor) = 1; + DECL_INITIAL (var) = ctor; + varpool_assemble_decl (varpool_node (var)); + + type = build_function_type_list (void_type_node, + build_pointer_type (TREE_TYPE (type)), + uptr, NULL_TREE); + decl = build_fn_decl ("__asan_register_globals", type); + TREE_NOTHROW (decl) = 1; + append_to_statement_list (build_call_expr (decl, 2, + build_fold_addr_expr (var), + build_int_cst (uptr, gcount)), + &ctor_statements); + + decl = build_fn_decl ("__asan_unregister_globals", type); + TREE_NOTHROW (decl) = 1; + append_to_statement_list (build_call_expr (decl, 2, + build_fold_addr_expr (var), + build_int_cst (uptr, gcount)), + &dtor_statements); + cgraph_build_static_cdtor ('D', dtor_statements, + MAX_RESERVED_INIT_PRIORITY - 1); + } cgraph_build_static_cdtor ('I', ctor_statements, - MAX_RESERVED_INIT_PRIORITY - 1); + MAX_RESERVED_INIT_PRIORITY - 1); } /* Initialize shadow_ptr_types array. */ --- gcc/asan.h.jj 2012-10-17 11:01:17.720950926 +0200 +++ gcc/asan.h 2012-10-17 11:01:05.669018002 +0200 @@ -23,6 +23,7 @@ along with GCC; see the file COPYING3. extern void asan_finish_file (void); extern rtx asan_emit_stack_protection (rtx, HOST_WIDE_INT *, tree *, int); +extern bool asan_protect_global (tree); /* Alias set for accessing the shadow memory. */ extern alias_set_type asan_shadow_set; @@ -56,4 +57,14 @@ asan_protect_stack_decl (tree decl) return DECL_P (decl) && !DECL_ARTIFICIAL (decl); } +/* Return the size of padding needed to insert after a protected + decl of SIZE. */ + +static inline unsigned int +asan_red_zone_size (unsigned int size) +{ + unsigned int c = size & (ASAN_RED_ZONE_SIZE - 1); + return c ? 2 * ASAN_RED_ZONE_SIZE - c : ASAN_RED_ZONE_SIZE; +} + #endif /* TREE_ASAN */