Message ID | ebab2c43-4fb6-0137-e292-4b6633e74b37@suse.cz |
---|---|
State | New |
Headers | show |
PING^1 On 06/20/2017 03:06 PM, Martin Liška wrote: > On 06/20/2017 11:32 AM, Jakub Jelinek wrote: >> On Tue, Jun 20, 2017 at 11:23:36AM +0200, Martin Liška wrote: >>>> Then something needs to be done for debugging too. If it is without VTA, >>>> then probably just having DECL_VALUE_EXPR is good enough, otherwise >>>> (VTA) you probably don't want that (or can reset it at that point), but >>>> instead emit after the initialization stmt a debug stmt that the variable >>>> value now lives in a different var. Though ideally we want the debugger >>>> to be able to also change the value of the var, that might be harder. >>>> With DECL_VALUE_EXPR on the other side the debug info will be incorrect in >>>> the prologue until it is assigned to the slot. >>> >>> Here I'm not sure about how to distinguish whether to build or not to build >>> the debug statement. According to flag_var_tracking? >> >> More like if (target_for_debug_bind (arg)) >> And if that is false, just make sure DECL_VALUE_EXPR is set to var. >> >>> You mean something like: >>> g = gimple_build_debug_bind (arg, var, g); >>> ? >> >> Well, there is no stmt, so the last argument would be just NULL. >> >>>> I don't understand the distinction. If you turn the original parm >>>> for complex/vector DECL_GIMPLE_REG_P, you should need the exact same code >>>> (but I think it would be better to use the default SSA_NAME of the PARM_DECL >>>> if it is a gimple reg type, rather than use the PARM_DECL itself >>>> and wait for update_ssa). >>> >>> Yes, the test-case /gcc/testsuite/g++.dg/asan/function-argument-3.C fails for me >>> as one needs to have a temporary SSA name, otherwise: >>> >>> /home/marxin/Programming/gcc/gcc/testsuite/g++.dg/asan/function-argument-3.C:13:1: error: invalid rhs for gimple memory store >>> foo (v4si arg) >>> ^~~ >>> arg >>> >>> arg >>> >>> # .MEM_4 = VDEF <.MEM_1(D)> >>> arg = arg; >>> during GIMPLE pass: sanopt >>> >>> If I see correctly the function in my test-case does not have default def SSA name for the parameter. >>> Thus I guess I need to create a SSA name? >> >> I'd expect if you have DECL_GIMPLE_REG_P set on the PARM_DECL and >> use the default def, you shouldn't run into this. >> >> Jakub >> > > Good I fixed that in v2, that passes regression tests. > Ale objections should be resolved in the version. > > Ready for trunk? > Martin >
On Tue, Jun 20, 2017 at 03:06:56PM +0200, Martin Liška wrote: > +/* Rewrite all usages of tree OP which is a PARM_DECL with a VAR_DECL > + that is it's DECL_VALUE_EXPR. */ > + > +static tree > +rewrite_usage_of_param (tree *op, int *walk_subtrees, void *) > +{ > + if (TREE_CODE (*op) == PARM_DECL && DECL_VALUE_EXPR (*op) != NULL_TREE) DECL_VALUE_EXPR testing is costly (it is a hash table lookup). Therefore you should test DECL_HAS_VALUE_EXPR_P (*op) after checking == PARM_DECL. And DECL_HAS_VALUE_EXPR_P should apply non-NULL DECL_VALUE_EXPR. That said, I wonder if we don't create DECL_VALUE_EXPR for PARM_DECLs in other parts of the compiler, whether it wouldn't be safer to also test here after == PARM_DECL and DECL_HAS_VALUE_EXPR_P check whether *op is in addressable_params hash table. > + { > + *op = DECL_VALUE_EXPR (*op); > + *walk_subtrees = 0; > + } > + > + return NULL; > +} > + > +/* For a given function FUN, rewrite all addressable parameters so that > + a new automatic variable is introduced. Right after function entry > + a parameter is assigned to the variable. */ > + > +static void > +sanitize_rewrite_addressable_params (function *fun) > +{ > + gimple *g; > + gimple_seq stmts = NULL; > + auto_vec<tree> addressable_params; You don't really use the addressable_params vector anywhere, right? Except for: > + > + for (tree arg = DECL_ARGUMENTS (current_function_decl); > + arg; arg = DECL_CHAIN (arg)) > + { > + if (TREE_ADDRESSABLE (arg) && !TREE_ADDRESSABLE (TREE_TYPE (arg))) > + { > + TREE_ADDRESSABLE (arg) = 0; > + /* The parameter is no longer addressable. */ > + tree type = TREE_TYPE (arg); > + addressable_params.safe_push (arg); pushing stuff into it and later > + if (addressable_params.is_empty ()) > + return; If you only need that, a bool flag if any params have been changed is enough. But see above whether it wouldn't be safer to use a hash table to verify it. Plus, I think it would be desirable to clear DECL_HAS_VALUE_EXPR_P and SET_DECL_VALUE_EXPR to NULL afterwards if (target_for_debug_bind (arg)) - whch can be done either the with vec or with a hash table traversal, for that we don't care about the ordering. > + > + /* Create a new automatic variable. */ > + tree var = build_decl (DECL_SOURCE_LOCATION (arg), > + VAR_DECL, DECL_NAME (arg), type); > + TREE_ADDRESSABLE (var) = 1; > + DECL_ARTIFICIAL (var) = 1; > + DECL_SEEN_IN_BIND_EXPR_P (var) = 0; This is 0 already from build_decl, IMHO no need to set it. > + gimple_add_tmp_var (var); > + > + if (dump_file) > + fprintf (dump_file, > + "Rewriting parameter whose address is taken: %s\n", > + IDENTIFIER_POINTER (DECL_NAME (arg))); > + > + SET_DECL_VALUE_EXPR (arg, var); But obviously you miss setting DECL_HAS_VALUE_EXPR_P here. > + /* Assign value of parameter to newly created variable. */ > + if ((TREE_CODE (type) == COMPLEX_TYPE > + || TREE_CODE (type) == VECTOR_TYPE)) > + { > + /* We need to create a SSA name that will be used for the > + assignment. */ Why don't you just set DECL_GIMPLE_REG_P (arg) = 1; for COMPLEX_TYPE/VECTOR_TYPE? The arg is going to be only used to copy it into the new var. And then just use get_or_create_ssa_default_def, regardless of whether if is complex/vector or other. > + /* Replace all usages of PARM_DECLs with the newly > + created variable VAR. */ > + basic_block bb; > + FOR_EACH_BB_FN (bb, fun) > + { > + gimple_stmt_iterator gsi; > + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) > + { > + gimple *stmt = gsi_stmt (gsi); > + gimple_stmt_iterator it = gsi_for_stmt (stmt); > + walk_gimple_stmt (&it, NULL, rewrite_usage_of_param, NULL); > + } > + for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) > + { > + gphi *phi = dyn_cast<gphi *> (gsi_stmt (gsi)); > + for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i) > + { > + hash_set<tree> visited_nodes; > + walk_tree (gimple_phi_arg_def_ptr (phi, i), > + rewrite_usage_of_param, NULL, &visited_nodes); > + } Doesn't walk_gimple_stmt on the PHI handle this? Jakub
From ed5da705250c3015e964de8d23d1aa3d0056012a Mon Sep 17 00:00:00 2001 From: marxin <mliska@suse.cz> Date: Wed, 14 Jun 2017 11:40:01 +0200 Subject: [PATCH] ASAN: handle addressable params (PR sanitize/81040). gcc/testsuite/ChangeLog: 2017-06-19 Martin Liska <mliska@suse.cz> PR sanitize/81040 * g++.dg/asan/function-argument-1.C: New test. * g++.dg/asan/function-argument-2.C: New test. * g++.dg/asan/function-argument-3.C: New test. gcc/ChangeLog: 2017-06-19 Martin Liska <mliska@suse.cz> PR sanitize/81040 * sanopt.c (rewrite_usage_of_param): New function. (sanitize_rewrite_addressable_params): Likewise. (pass_sanopt::execute): Call rewrite_usage_of_param. --- gcc/sanopt.c | 132 ++++++++++++++++++++++++ gcc/testsuite/g++.dg/asan/function-argument-1.C | 30 ++++++ gcc/testsuite/g++.dg/asan/function-argument-2.C | 24 +++++ gcc/testsuite/g++.dg/asan/function-argument-3.C | 27 +++++ 4 files changed, 213 insertions(+) create mode 100644 gcc/testsuite/g++.dg/asan/function-argument-1.C create mode 100644 gcc/testsuite/g++.dg/asan/function-argument-2.C create mode 100644 gcc/testsuite/g++.dg/asan/function-argument-3.C diff --git a/gcc/sanopt.c b/gcc/sanopt.c index 16bdba76042..077811b5b93 100644 --- a/gcc/sanopt.c +++ b/gcc/sanopt.c @@ -37,6 +37,12 @@ along with GCC; see the file COPYING3. If not see #include "gimple-ssa.h" #include "tree-phinodes.h" #include "ssa-iterators.h" +#include "gimplify.h" +#include "gimple-iterator.h" +#include "gimple-walk.h" +#include "cfghooks.h" +#include "tree-dfa.h" +#include "tree-ssa.h" /* This is used to carry information about basic blocks. It is attached to the AUX field of the standard CFG block. */ @@ -858,6 +864,129 @@ sanitize_asan_mark_poison (void) } } +/* Rewrite all usages of tree OP which is a PARM_DECL with a VAR_DECL + that is it's DECL_VALUE_EXPR. */ + +static tree +rewrite_usage_of_param (tree *op, int *walk_subtrees, void *) +{ + if (TREE_CODE (*op) == PARM_DECL && DECL_VALUE_EXPR (*op) != NULL_TREE) + { + *op = DECL_VALUE_EXPR (*op); + *walk_subtrees = 0; + } + + return NULL; +} + +/* For a given function FUN, rewrite all addressable parameters so that + a new automatic variable is introduced. Right after function entry + a parameter is assigned to the variable. */ + +static void +sanitize_rewrite_addressable_params (function *fun) +{ + gimple *g; + gimple_seq stmts = NULL; + auto_vec<tree> addressable_params; + + for (tree arg = DECL_ARGUMENTS (current_function_decl); + arg; arg = DECL_CHAIN (arg)) + { + if (TREE_ADDRESSABLE (arg) && !TREE_ADDRESSABLE (TREE_TYPE (arg))) + { + TREE_ADDRESSABLE (arg) = 0; + /* The parameter is no longer addressable. */ + tree type = TREE_TYPE (arg); + addressable_params.safe_push (arg); + + /* Create a new automatic variable. */ + tree var = build_decl (DECL_SOURCE_LOCATION (arg), + VAR_DECL, DECL_NAME (arg), type); + TREE_ADDRESSABLE (var) = 1; + DECL_ARTIFICIAL (var) = 1; + DECL_SEEN_IN_BIND_EXPR_P (var) = 0; + + gimple_add_tmp_var (var); + + if (dump_file) + fprintf (dump_file, + "Rewriting parameter whose address is taken: %s\n", + IDENTIFIER_POINTER (DECL_NAME (arg))); + + SET_DECL_VALUE_EXPR (arg, var); + + /* Assign value of parameter to newly created variable. */ + if ((TREE_CODE (type) == COMPLEX_TYPE + || TREE_CODE (type) == VECTOR_TYPE)) + { + /* We need to create a SSA name that will be used for the + assignment. */ + tree tmp; + if (DECL_GIMPLE_REG_P (arg)) + tmp = ssa_default_def (cfun, arg); + else + { + tmp = make_ssa_name (type); + g = gimple_build_assign (tmp, arg); + gimple_set_location (g, DECL_SOURCE_LOCATION (arg)); + gimple_seq_add_stmt (&stmts, g); + } + g = gimple_build_assign (var, tmp); + gimple_set_location (g, DECL_SOURCE_LOCATION (arg)); + gimple_seq_add_stmt (&stmts, g); + } + else + { + dump_function (0, cfun->decl); + g = gimple_build_assign (var, arg); + gimple_set_location (g, DECL_SOURCE_LOCATION (arg)); + gimple_seq_add_stmt (&stmts, g); + } + + if (target_for_debug_bind (arg)) + { + g = gimple_build_debug_bind (arg, var, NULL); + gimple_seq_add_stmt (&stmts, g); + } + } + } + + if (addressable_params.is_empty ()) + return; + + /* Replace all usages of PARM_DECLs with the newly + created variable VAR. */ + basic_block bb; + FOR_EACH_BB_FN (bb, fun) + { + gimple_stmt_iterator gsi; + for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple *stmt = gsi_stmt (gsi); + gimple_stmt_iterator it = gsi_for_stmt (stmt); + walk_gimple_stmt (&it, NULL, rewrite_usage_of_param, NULL); + } + for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gphi *phi = dyn_cast<gphi *> (gsi_stmt (gsi)); + for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i) + { + hash_set<tree> visited_nodes; + walk_tree (gimple_phi_arg_def_ptr (phi, i), + rewrite_usage_of_param, NULL, &visited_nodes); + } + } + } + + /* Insert default assignments at the beginning of a function. */ + basic_block entry_bb = ENTRY_BLOCK_PTR_FOR_FN (fun); + entry_bb = split_edge (single_succ_edge (entry_bb)); + + gimple_stmt_iterator gsi = gsi_start_bb (entry_bb); + gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT); +} + unsigned int pass_sanopt::execute (function *fun) { @@ -891,6 +1020,9 @@ pass_sanopt::execute (function *fun) sanitize_asan_mark_poison (); } + if (asan_sanitize_stack_p ()) + sanitize_rewrite_addressable_params (fun); + bool use_calls = ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD < INT_MAX && asan_num_accesses >= ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD; diff --git a/gcc/testsuite/g++.dg/asan/function-argument-1.C b/gcc/testsuite/g++.dg/asan/function-argument-1.C new file mode 100644 index 00000000000..148c4628316 --- /dev/null +++ b/gcc/testsuite/g++.dg/asan/function-argument-1.C @@ -0,0 +1,30 @@ +// { dg-do run } +// { dg-shouldfail "asan" } + +struct A +{ + int a[5]; +}; + +static __attribute__ ((noinline)) int +goo (A *a) +{ + int *ptr = &a->a[0]; + return *(volatile int *) (ptr - 1); +} + +__attribute__ ((noinline)) int +foo (A arg) +{ + return goo (&arg); +} + +int +main () +{ + return foo (A ()); +} + +// { dg-output "ERROR: AddressSanitizer: stack-buffer-underflow on address.*(\n|\r\n|\r)" } +// { dg-output "READ of size . at.*" } +// { dg-output ".*'arg' <== Memory access at offset \[0-9\]* underflows this variable.*" } diff --git a/gcc/testsuite/g++.dg/asan/function-argument-2.C b/gcc/testsuite/g++.dg/asan/function-argument-2.C new file mode 100644 index 00000000000..3a7c33bdaaa --- /dev/null +++ b/gcc/testsuite/g++.dg/asan/function-argument-2.C @@ -0,0 +1,24 @@ +// { dg-do run } +// { dg-shouldfail "asan" } + +static __attribute__ ((noinline)) int +goo (int *a) +{ + return *(volatile int *)a; +} + +__attribute__ ((noinline)) int +foo (char arg) +{ + return goo ((int *)&arg); +} + +int +main () +{ + return foo (12); +} + +// { dg-output "ERROR: AddressSanitizer: stack-buffer-overflow on address.*(\n|\r\n|\r)" } +// { dg-output "READ of size . at.*" } +// { dg-output ".*'arg' <== Memory access at offset \[0-9\]* partially overflows this variable.*" } diff --git a/gcc/testsuite/g++.dg/asan/function-argument-3.C b/gcc/testsuite/g++.dg/asan/function-argument-3.C new file mode 100644 index 00000000000..14617ba8425 --- /dev/null +++ b/gcc/testsuite/g++.dg/asan/function-argument-3.C @@ -0,0 +1,27 @@ +// { dg-do run } +// { dg-shouldfail "asan" } + +typedef int v4si __attribute__ ((vector_size (16))); + +static __attribute__ ((noinline)) int +goo (v4si *a) +{ + return (*(volatile v4si *) (a + 1))[2]; +} + +__attribute__ ((noinline)) int +foo (v4si arg) +{ + return goo (&arg); +} + +int +main () +{ + v4si v = {1,2,3,4}; + return foo (v); +} + +// { dg-output "ERROR: AddressSanitizer: stack-buffer-overflow on address.*(\n|\r\n|\r)" } +// { dg-output "READ of size . at.*" } +// { dg-output ".*'arg' <== Memory access at offset \[0-9\]* overflows this variable.*" } -- 2.13.1