@@ -888,6 +888,8 @@ c_cpp_builtins (cpp_reader *pfile)
/* Make the choice of the stack protector runtime visible to source code.
The macro names and values here were chosen for compatibility with an
earlier implementation, i.e. ProPolice. */
+ if (flag_stack_protect == 3)
+ cpp_define (pfile, "__SSP_STRONG__=3");
if (flag_stack_protect == 2)
cpp_define (pfile, "__SSP_ALL__=2");
else if (flag_stack_protect == 1)
@@ -1291,6 +1291,10 @@ clear_tree_used (tree block)
clear_tree_used (t);
}
+#define SPCT_FLAG_ALL 2
+#define SPCT_FLAG_DEFAULT 1
+#define SPCT_FLAG_STRONG 3
+
/* Examine TYPE and determine a bit mask of the following features. */
#define SPCT_HAS_LARGE_CHAR_ARRAY 1
@@ -1360,7 +1364,8 @@ stack_protect_decl_phase (tree decl)
if (bits & SPCT_HAS_SMALL_CHAR_ARRAY)
has_short_buffer = true;
- if (flag_stack_protect == 2)
+ if (flag_stack_protect == SPCT_FLAG_ALL ||
+ flag_stack_protect == SPCT_FLAG_STRONG)
{
if ((bits & (SPCT_HAS_SMALL_CHAR_ARRAY | SPCT_HAS_LARGE_CHAR_ARRAY))
&& !(bits & SPCT_HAS_AGGREGATE))
@@ -1514,6 +1519,29 @@ estimated_stack_frame_size (struct cgraph_node *node)
return size;
}
+/* Helper routine to check if a record or union contains an array field. */
+
+static int
+record_or_union_type_has_array_p (const_tree tree_type)
+{
+ tree fields = TYPE_FIELDS (tree_type);
+ tree f;
+
+ for (f = fields; f; f = DECL_CHAIN (f))
+ {
+ if (TREE_CODE (f) == FIELD_DECL)
+ {
+ tree field_type = TREE_TYPE (f);
+ if (RECORD_OR_UNION_TYPE_P (field_type)
+ && record_or_union_type_has_array_p (field_type))
+ return 1;
+ if (TREE_CODE (field_type) == ARRAY_TYPE)
+ return 1;
+ }
+ }
+ return 0;
+}
+
/* Expand all variables used in the function. */
static rtx
@@ -1525,6 +1553,7 @@ expand_used_vars (void)
struct pointer_map_t *ssa_name_decls;
unsigned i;
unsigned len;
+ int gen_stack_protect_signal = 0;
/* Compute the phase of the stack frame for this function. */
{
@@ -1576,6 +1605,23 @@ expand_used_vars (void)
}
pointer_map_destroy (ssa_name_decls);
+ FOR_EACH_LOCAL_DECL (cfun, i, var)
+ if (!is_global_var (var))
+ {
+ tree var_type = TREE_TYPE (var);
+ /* Examine local referenced variables that have their addresses taken,
+ contain an array, or are arrays. */
+ if (TREE_CODE (var) == VAR_DECL
+ && (TREE_CODE (var_type) == ARRAY_TYPE
+ || TREE_ADDRESSABLE (var)
+ || (RECORD_OR_UNION_TYPE_P (var_type)
+ && record_or_union_type_has_array_p (var_type))))
+ {
+ ++gen_stack_protect_signal;
+ break;
+ }
+ }
+
/* At this point all variables on the local_decls with TREE_USED
set are not associated with any block scope. Lay them out. */
@@ -1662,11 +1708,18 @@ expand_used_vars (void)
dump_stack_var_partition ();
}
- /* There are several conditions under which we should create a
- stack guard: protect-all, alloca used, protected decls present. */
- if (flag_stack_protect == 2
- || (flag_stack_protect
- && (cfun->calls_alloca || has_protected_decls)))
+ /* Create stack guard, if
+ a) "-fstack-protector-all" - always;
+ b) "-fstack-protector-strong" - if there are arrays, memory
+ references to local variables, alloca used, or protected decls present;
+ c) "-fstack-protector" - if alloca used, or protected decls present */
+ if (flag_stack_protect == SPCT_FLAG_ALL
+ || (flag_stack_protect == SPCT_FLAG_STRONG
+ && (gen_stack_protect_signal || cfun->calls_alloca
+ || has_protected_decls))
+ || (flag_stack_protect == SPCT_FLAG_DEFAULT
+ && (cfun->calls_alloca
+ || has_protected_decls)))
create_stack_guard ();
/* Assign rtl to each variable based on these partitions. */
@@ -1914,6 +1914,10 @@ fstack-protector-all
Common Report RejectNegative Var(flag_stack_protect, 2)
Use a stack protection method for every function
+fstack-protector-strong
+Common Report RejectNegative Var(flag_stack_protect, 3)
+Use a smart stack protection method for certain functions
+
fstack-usage
Common RejectNegative Var(flag_stack_usage)
Output stack usage information on a per-function basis
@@ -2349,6 +2349,10 @@ use.
This macro is defined, with value 2, when @option{-fstack-protector-all} is
in use.
+@item __SSP_STRONG__
+This macro is defined, with value 3, when @option{-fstack-protector-strong} is
+in use.
+
@item __SANITIZE_ADDRESS__
This macro is defined, with value 1, when @option{-fsanitize=address} is
in use.
@@ -406,8 +406,8 @@ Objective-C and Objective-C++ Dialects}.
-fsel-sched-pipelining -fsel-sched-pipelining-outer-loops @gol
-fshrink-wrap -fsignaling-nans -fsingle-precision-constant @gol
-fsplit-ivs-in-unroller -fsplit-wide-types -fstack-protector @gol
--fstack-protector-all -fstrict-aliasing -fstrict-overflow @gol
--fthread-jumps -ftracer -ftree-bit-ccp @gol
+-fstack-protector-all -fstack-protector-strong -fstrict-aliasing @gol
+-fstrict-overflow -fthread-jumps -ftracer -ftree-bit-ccp @gol
-ftree-builtin-call-dce -ftree-ccp -ftree-ch @gol
-ftree-coalesce-inline-vars -ftree-coalesce-vars -ftree-copy-prop @gol
-ftree-copyrename -ftree-dce -ftree-dominator-opts -ftree-dse @gol
@@ -8880,6 +8880,12 @@ If a guard check fails, an error message is
printed and the program exits.
@opindex fstack-protector-all
Like @option{-fstack-protector} except that all functions are protected.
+@item -fstack-protector-strong
+@opindex fstack-protector-strong
+Like @option{-fstack-protector-strong} but includes additional functions to be
+protected - those that have local array definitions, or have
references to local
+frame addresses.
+
@item -fsection-anchors
@opindex fsection-anchors
Try to reduce the number of symbolic address calculations by using
@@ -655,7 +655,7 @@ proper position among the other output files. */
#ifdef TARGET_LIBC_PROVIDES_SSP
#define LINK_SSP_SPEC "%{fstack-protector:}"
#else
-#define LINK_SSP_SPEC
"%{fstack-protector|fstack-protector-all:-lssp_nonshared -lssp}"
+#define LINK_SSP_SPEC
"%{fstack-protector|fstack-protector-strong|fstack-protector-all:-lssp_nonshared
-lssp}"
#endif
#endif
b/gcc/testsuite/g++.dg/fstack-protector-strong.C
new file mode 100644
@@ -0,0 +1,35 @@
+/* Test that stack protection is done on chosen functions. */
+
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 -fstack-protector-strong" } */
+
+class A
+{
+public:
+ A() {}
+ ~A() {}
+ void method();
+ int state;
+};
+
+/* Frame address exposed to A::method via "this". */
+int
+foo1 ()
+{
+ A a;
+ a.method ();
+ return a.state;
+}
+
+/* Possible destroying foo2's stack via &a. */
+int
+global_func (A& a);
+
+/* Frame address exposed to global_func. */
+int foo2 ()
+{
+ A a;
+ return global_func (a);
+}
+
+/* { dg-final { scan-assembler-times "stack_chk_fail" 2 } } */
b/gcc/testsuite/gcc.dg/fstack-protector-strong.c
new file mode 100644
@@ -0,0 +1,135 @@
+/* Test that stack protection is done on chosen functions. */
+
+/* { dg-do compile { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 -fstack-protector-strong" } */
+
+#include<string.h>
+#include<stdlib.h>
+
+extern int g0;
+extern int* pg0;
+int
+goo (int *);
+int
+hoo (int);
+
+/* Function frame address escaped function call. */
+int
+foo1 ()
+{
+ int i;
+ return goo (&i);
+}
+
+struct ArrayStruct
+{
+ int a;
+ int array[10];
+};
+
+struct AA
+{
+ int b;
+ struct ArrayStruct as;
+};
+
+/* Function frame contains array. */
+int
+foo2 ()
+{
+ struct AA aa;
+ int i;
+ for (i = 0; i < 10; ++i)
+ {
+ aa.as.array[i] = i * (i-1) + i / 2;
+ }
+ return aa.as.array[5];
+}
+
+/* Address computation based on a function frame address. */
+int
+foo3 ()
+{
+ int a;
+ int *p;
+ p = &a + 5;
+ return goo (p);
+}
+
+/* Address cast based on a function frame address. */
+int
+foo4 ()
+{
+ int a;
+ return goo (g0 << 2 ? (int *)(3 * (long)(void *)(&a)) : 0);
+}
+
+/* Address cast based on a local array. */
+int
+foo5 ()
+{
+ short array[10];
+ return goo ((int *)(array + 5));
+}
+
+struct BB
+{
+ int one;
+ int two;
+ int three;
+};
+
+/* Address computaton based on a function frame address.*/
+int
+foo6 ()
+{
+ struct BB bb;
+ return goo (&bb.one + sizeof(int));
+}
+
+/* Function frame address escaped via global variable. */
+int
+foo7 ()
+{
+ int a;
+ pg0 = &a;
+ goo (pg0);
+ return *pg0;
+}
+
+/* Check that this covers -fstack-protector. */
+int
+foo8 ()
+{
+ char base[100];
+ memcpy ((void *)base, (const void *)pg0, 105);
+ return (int)(base[32]);
+}
+
+/* Check that this covers -fstack-protector. */
+int
+foo9 ()
+{
+ char* p = alloca (100);
+ return goo ((int *)(p + 50));
+}
+
+int
+global2 (struct BB* pbb);
+
+/* Address taken on struct. */
+int
+foo10 ()
+{
+ struct BB bb;
+ int i;
+ bb.one = global2 (&bb);
+ for (i = 0; i < 10; ++i)
+ {
+ bb.two = bb.one + bb.two;
+ bb.three = bb.one + bb.two + bb.three;
+ }
+ return bb.three;
+}
+
+/* { dg-final { scan-assembler-times "stack_chk_fail" 10 } } */