const gcall *call, unsigned int num_args);
extern bool is_setjmp_call_p (const gcall *call);
extern bool is_longjmp_call_p (const gcall *call);
+extern bool is_placement_new_p (const gcall *call);
extern const char *get_user_facing_name (const gcall *call);
return m_model->get_rvalue (arg, m_ctxt);
}
+/* If argument IDX's svalue at the callsite is of pointer type,
+ return the region it points to.
+ Otherwise return NULL. */
+
+const region *
+call_details::deref_ptr_arg (unsigned idx) const
+{
+ const svalue *ptr_sval = get_arg_svalue (idx);
+ return m_model->deref_rvalue (ptr_sval, get_arg_tree (idx), m_ctxt);
+}
+
/* Attempt to get the string literal for argument IDX, or return NULL
otherwise.
For use when implementing "__analyzer_*" functions that take
tree get_arg_tree (unsigned idx) const;
tree get_arg_type (unsigned idx) const;
const svalue *get_arg_svalue (unsigned idx) const;
+ const region *deref_ptr_arg (unsigned idx) const;
const char *get_arg_string_literal (unsigned idx) const;
tree get_fndecl_for_call () const;
#if ENABLE_ANALYZER
+/* Return true if CALL is a non-allocating operator new or operator new []
+ that contains no user-defined args, i.e. having any signature of:
+
+ - void* operator new (std::size_t count, void* ptr);
+ - void* operator new[] (std::size_t count, void* ptr);
+
+ See https://en.cppreference.com/w/cpp/memory/new/operator_new. */
+
+bool is_placement_new_p (const gcall *call)
+{
+ gcc_assert (call);
+ tree fndecl = gimple_call_fndecl (call);
+
+ if (!fndecl || TREE_CODE (TREE_TYPE (fndecl)) == METHOD_TYPE)
+ /* Give up on overloaded operator new. */
+ return false;
+
+ if (!is_named_call_p (fndecl, "operator new", call, 2)
+ && !is_named_call_p (fndecl, "operator new []", call, 2))
+ return false;
+
+ /* We must distinguish between an allocating non-throwing new
+ and a non-allocating new.
+
+ The former might have one of the following signatures :
+ void* operator new (std::size_t count, const std::nothrow_t& tag);
+ void* operator new[] (std::size_t count, const std::nothrow_t& tag);
+ Whereas a placement new would take a pointer. */
+ tree arg1_type = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fndecl)));
+ return TREE_CODE (TREE_VALUE (arg1_type)) == POINTER_TYPE;
+}
+
namespace ana {
/* Implementations of specific functions. */
public:
bool matches_call_types_p (const call_details &cd) const final override
{
- return cd.num_args () == 1;
+ return (cd.num_args () == 1
+ && cd.arg_is_size_p (0))
+ || (cd.num_args () == 2
+ && cd.arg_is_size_p (0)
+ && POINTER_TYPE_P (cd.get_arg_type (1)));
}
void impl_call_pre (const call_details &cd) const final override
region_model *model = cd.get_model ();
region_model_manager *mgr = cd.get_manager ();
const svalue *size_sval = cd.get_arg_svalue (0);
- const region *new_reg
- = model->get_or_create_region_for_heap_alloc (size_sval, cd.get_ctxt ());
- if (cd.get_lhs_type ())
+ region_model_context *ctxt = cd.get_ctxt ();
+ const gcall *call = cd.get_call_stmt ();
+
+ /* If the call was actually a placement new, check that accessing
+ the buffer lhs is placed into does not result in out-of-bounds. */
+ if (is_placement_new_p (call))
{
- const svalue *ptr_sval
- = mgr->get_ptr_svalue (cd.get_lhs_type (), new_reg);
- cd.maybe_set_lhs (ptr_sval);
+ const region *ptr_reg = cd.deref_ptr_arg (1);
+ if (ptr_reg && cd.get_lhs_type ())
+ {
+ const svalue *num_bytes_sval = cd.get_arg_svalue (0);
+ const region *sized_new_reg
+ = mgr->get_sized_region (ptr_reg,
+ cd.get_lhs_type (),
+ num_bytes_sval);
+ model->check_region_for_write (sized_new_reg,
+ nullptr,
+ ctxt);
+ const svalue *ptr_sval
+ = mgr->get_ptr_svalue (cd.get_lhs_type (), sized_new_reg);
+ cd.maybe_set_lhs (ptr_sval);
+ }
+ }
+ /* If the call is an allocating new, then create a heap allocated
+ region. */
+ else
+ {
+ const region *new_reg
+ = model->get_or_create_region_for_heap_alloc (size_sval, ctxt);
+ if (cd.get_lhs_type ())
+ {
+ const svalue *ptr_sval
+ = mgr->get_ptr_svalue (cd.get_lhs_type (), new_reg);
+ cd.maybe_set_lhs (ptr_sval);
+ }
+ }
+ }
+
+ void impl_call_post (const call_details &cd) const final override
+ {
+ region_model *model = cd.get_model ();
+ region_model_manager *mgr = cd.get_manager ();
+ tree callee_fndecl = cd.get_fndecl_for_call ();
+ region_model_context *ctxt = cd.get_ctxt ();
+
+ /* If the call is guaranteed to return nonnull
+ then add a nonnull constraint to the allocated region. */
+ if (!TREE_NOTHROW (callee_fndecl) && flag_exceptions)
+ {
+ const svalue *null_sval
+ = mgr->get_or_create_null_ptr (cd.get_lhs_type ());
+ const svalue *result
+ = model->get_store_value (cd.get_lhs_region (), ctxt);
+ model->add_constraint (result, NE_EXPR, null_sval, ctxt);
}
}
};
-/* Handler for "operator delete", both the sized and unsized variants
- (2 arguments and 1 argument respectively), and for "operator delete []" */
+/* Handler for "operator delete" and for "operator delete []",
+ both the sized and unsized variants
+ (2 arguments and 1 argument respectively). */
class kf_operator_delete : public known_function
{
public:
- kf_operator_delete (unsigned num_args) : m_num_args (num_args) {}
-
bool matches_call_types_p (const call_details &cd) const final override
{
- return cd.num_args () == m_num_args;
+ return cd.num_args () == 1 or cd.num_args () == 2;
}
void impl_call_post (const call_details &cd) const final override
{
/* If the ptr points to an underlying heap region, delete it,
poisoning pointers. */
- model->unbind_region_and_descendents (freed_reg, POISON_KIND_FREED);
+ model->unbind_region_and_descendents (freed_reg,
+ POISON_KIND_DELETED);
}
}
-private:
- unsigned m_num_args;
};
/* Populate KFM with instances of known functions relating to C++. */
{
kfm.add ("operator new", make_unique<kf_operator_new> ());
kfm.add ("operator new []", make_unique<kf_operator_new> ());
- kfm.add ("operator delete", make_unique<kf_operator_delete> (1));
- kfm.add ("operator delete", make_unique<kf_operator_delete> (2));
- kfm.add ("operator delete []", make_unique<kf_operator_delete> (1));
+ kfm.add ("operator delete", make_unique<kf_operator_delete> ());
+ kfm.add ("operator delete []", make_unique<kf_operator_delete> ());
}
} // namespace ana
case POISON_KIND_UNINIT:
return OPT_Wanalyzer_use_of_uninitialized_value;
case POISON_KIND_FREED:
+ case POISON_KIND_DELETED:
return OPT_Wanalyzer_use_after_free;
case POISON_KIND_POPPED_STACK:
return OPT_Wanalyzer_use_of_pointer_in_stale_stack_frame;
m_expr);
}
break;
+ case POISON_KIND_DELETED:
+ {
+ diagnostic_metadata m;
+ m.add_cwe (416); /* "CWE-416: Use After Free". */
+ return warning_meta (rich_loc, m, get_controlling_option (),
+ "use after %<delete%> of %qE",
+ m_expr);
+ }
+ break;
case POISON_KIND_POPPED_STACK:
{
/* TODO: which CWE? */
case POISON_KIND_FREED:
return ev.formatted_print ("use after %<free%> of %qE here",
m_expr);
+ case POISON_KIND_DELETED:
+ return ev.formatted_print ("use after %<delete%> of %qE here",
+ m_expr);
case POISON_KIND_POPPED_STACK:
return ev.formatted_print
("dereferencing pointer %qE to within stale stack frame",
}
}
+ /* Attempt to unwrap cast if there is one, and the types match. */
+ tree lhs_type = lhs->get_type ();
+ tree rhs_type = rhs->get_type ();
+ if (lhs_type && rhs_type)
+ {
+ const unaryop_svalue *lhs_un_op = dyn_cast <const unaryop_svalue *> (lhs);
+ const unaryop_svalue *rhs_un_op = dyn_cast <const unaryop_svalue *> (rhs);
+ if (lhs_un_op && CONVERT_EXPR_CODE_P (lhs_un_op->get_op ())
+ && rhs_un_op && CONVERT_EXPR_CODE_P (rhs_un_op->get_op ())
+ && lhs_type == rhs_type)
+ return eval_condition (lhs_un_op->get_arg (),
+ op,
+ rhs_un_op->get_arg ());
+
+ else if (lhs_un_op && CONVERT_EXPR_CODE_P (lhs_un_op->get_op ())
+ && lhs_type == rhs_type)
+ return eval_condition (lhs_un_op->get_arg (), op, rhs);
+
+ else if (rhs_un_op && CONVERT_EXPR_CODE_P (rhs_un_op->get_op ())
+ && lhs_type == rhs_type)
+ return eval_condition (lhs, op, rhs_un_op->get_arg ());
+ }
+
/* Otherwise, try constraints.
Cast to const to ensure we don't change the constraint_manager as we
do this (e.g. by creating equivalence classes). */
override
{
if (change.m_old_state == m_sm.get_start_state ()
- && unchecked_p (change.m_new_state))
+ && (unchecked_p (change.m_new_state) || nonnull_p (change.m_new_state)))
// TODO: verify that it's the allocation stmt, not a copy
return label_text::borrow ("allocated here");
if (unchecked_p (change.m_old_state)
{
return ev.formatted_print ("dereference of NULL %qE", ev.m_expr);
}
+
+ /* Implementation of pending_diagnostic::supercedes_p for
+ null-deref.
+
+ We want null-deref to supercede use-of-unitialized-value,
+ so that if we have these at the same stmt, we don't emit
+ a use-of-uninitialized, just the null-deref. */
+
+ bool supercedes_p (const pending_diagnostic &other) const final override
+ {
+ if (other.use_of_uninit_p ())
+ return true;
+
+ return false;
+ }
};
/* Concrete subclass for describing passing a NULL value to a
return true;
}
- if (is_named_call_p (callee_fndecl, "operator new", call, 1))
- on_allocator_call (sm_ctxt, call, &m_scalar_delete);
- else if (is_named_call_p (callee_fndecl, "operator new []", call, 1))
- on_allocator_call (sm_ctxt, call, &m_vector_delete);
- else if (is_named_call_p (callee_fndecl, "operator delete", call, 1)
- || is_named_call_p (callee_fndecl, "operator delete", call, 2))
+ if (!is_placement_new_p (call))
+ {
+ bool returns_nonnull = !TREE_NOTHROW (callee_fndecl)
+ && flag_exceptions;
+ if (is_named_call_p (callee_fndecl, "operator new"))
+ on_allocator_call (sm_ctxt, call,
+ &m_scalar_delete, returns_nonnull);
+ else if (is_named_call_p (callee_fndecl, "operator new []"))
+ on_allocator_call (sm_ctxt, call,
+ &m_vector_delete, returns_nonnull);
+ }
+
+ if (is_named_call_p (callee_fndecl, "operator delete", call, 1)
+ || is_named_call_p (callee_fndecl, "operator delete", call, 2))
{
on_deallocator_call (sm_ctxt, node, call,
&m_scalar_delete.m_deallocator, 0);
return "uninit";
case POISON_KIND_FREED:
return "freed";
+ case POISON_KIND_DELETED:
+ return "deleted";
case POISON_KIND_POPPED_STACK:
return "popped stack";
}
/* For use to describe freed memory. */
POISON_KIND_FREED,
+ /* For use to describe deleted memory. */
+ POISON_KIND_DELETED,
+
/* For use on pointers to regions within popped stack frames. */
POISON_KIND_POPPED_STACK
};
--- /dev/null
+// { dg-additional-options "-O0 -fno-analyzer-suppress-followups -fexceptions" }
+#include <new>
+
+struct A
+{
+ int x;
+ int y;
+};
+
+void test_spurious_null_warning_throwing ()
+{
+ int *x = new int; /* { dg-bogus "dereference of possibly-NULL" } */
+ int *y = new int (); /* { dg-bogus "dereference of possibly-NULL" "non-throwing" } */
+ int *arr = new int[3]; /* { dg-bogus "dereference of possibly-NULL" } */
+ A *a = new A (); /* { dg-bogus "dereference of possibly-NULL" "throwing new cannot be null" } */
+
+ int z = *y + 2;
+ z = *x + 4; /* { dg-bogus "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1 } */
+ z = arr[0] + 4; /* { dg-bogus "dereference of possibly-NULL" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* } .-1 } */
+
+ delete a;
+ delete y;
+ delete x;
+ delete[] arr;
+}
+
+void test_default_initialization ()
+{
+ int *y = ::new int;
+ int *x = ::new int (); /* { dg-bogus "dereference of possibly-NULL 'operator new" } */
+
+ int b = *x + 3; /* { dg-bogus "dereference of possibly-NULL" } */
+ /* { dg-bogus "use of uninitialized ‘*x’" "" { target *-*-* } .-1 } */
+ int a = *y + 2; /* { dg-bogus "dereference of possibly-NULL 'y'" } */
+ /* { dg-warning "use of uninitialized value '\\*y'" "no default init" { target *-*-* } .-1 } */
+
+ delete x;
+ delete y;
+}
+
+/* From clang core.uninitialized.NewArraySize
+new[] should not be called with an undefined size argument */
+
+void test_garbage_new_array ()
+{
+ int n;
+ int *arr = ::new int[n]; /* { dg-warning "use of uninitialized value 'n'" } */
+ arr[0] = 7;
+ ::delete[] arr; /* no warnings emitted here either */
+}
+
+void test_nonthrowing ()
+{
+ int* x = new(std::nothrow) int;
+ int* y = new(std::nothrow) int();
+ int* arr = new(std::nothrow) int[10];
+
+ int z = *y + 2; /* { dg-warning "dereference of NULL 'y'" } */
+ /* { dg-bogus "use of uninitialized value '\\*y'" "" { target *-*-* } .-1 } */
+ z = *x + 4; /* { dg-warning "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1 } */
+ z = arr[0] + 4; /* { dg-warning "dereference of possibly-NULL 'arr'" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* } .-1 } */
+
+ delete y;
+ delete x;
+ delete[] arr;
+}
--- /dev/null
+/* { dg-additional-options "-O0 -fno-exceptions -fno-analyzer-suppress-followups" } */
+#include <new>
+
+/* Test non-throwing variants of operator new */
+
+struct A
+{
+ int x;
+ int y;
+};
+
+void test_throwing ()
+{
+ int* x = new int;
+ int* y = new int(); /* { dg-warning "dereference of possibly-NULL" } */
+ int* arr = new int[10];
+ A *a = new A(); /* { dg-warning "dereference of possibly-NULL" } */
+
+ int z = *y + 2;
+ z = *x + 4; /* { dg-warning "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1 } */
+ z = arr[0] + 4; /* { dg-warning "dereference of possibly-NULL 'arr'" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* } .-1 } */
+ a->y = a->x + 3;
+
+ delete a;
+ delete y;
+ delete x;
+ delete[] arr;
+}
+
+void test_nonthrowing ()
+{
+ int* x = new(std::nothrow) int;
+ int* y = new(std::nothrow) int();
+ int* arr = new(std::nothrow) int[10];
+
+ int z = *y + 2; /* { dg-warning "dereference of NULL 'y'" } */
+ /* { dg-bogus "use of uninitialized value '\\*y'" "" { target *-*-* } .-1 } */
+ z = *x + 4; /* { dg-warning "dereference of possibly-NULL 'x'" } */
+ /* { dg-warning "use of uninitialized value '\\*x'" "" { target *-*-* } .-1 } */
+ z = arr[0] + 4; /* { dg-warning "dereference of possibly-NULL 'arr'" } */
+ /* { dg-warning "use of uninitialized value '\\*arr'" "" { target *-*-* } .-1 } */
+
+ delete y;
+ delete x;
+ delete[] arr;
+}
int test (int_container ic)
{
- int_and_addr *iaddr = new (ic.addr ()) int_and_addr;
+ int_and_addr *iaddr = new (ic.addr ()) int_and_addr; /* { dg-warning "stack-based buffer overflow" } */
return iaddr->i;
}
--- /dev/null
+/* { dg-additional-options "-Wno-placement-new -Wno-analyzer-use-of-uninitialized-value" } */
+
+#include <new>
+#include <stdlib.h>
+
+extern int get_buf_size ();
+
+void var_too_short ()
+{
+ int8_t s;
+ int64_t *lp = new (&s) int64_t; /* { dg-warning "stack-based buffer overflow" } */
+ /* { dg-warning "allocated buffer size is not a multiple of the pointee's size" "" { target *-*-* } .-1 } */
+}
+
+void static_buffer_too_short ()
+{
+ int n = 16;
+ int buf[n];
+ int *p = new (buf) int[n + 1]; /* { dg-warning "stack-based buffer overflow" } */
+}
+
+void symbolic_buffer_too_short ()
+{
+ int n = get_buf_size ();
+ char buf[n];
+ char *p = new (buf) char[n + 10]; /* { dg-warning "stack-based buffer overflow" } */
+}
+
+void test_binop ()
+{
+ char *p = (char *) malloc (4);
+ if (!p)
+ return;
+ int32_t *i = ::new (p + 1) int32_t; /* { dg-warning "heap-based buffer overflow" } */
+ *i = 42; /* { dg-warning "heap-based buffer overflow" } */
+ free (p);
+}
\ No newline at end of file
{
char buf[sizeof(int) * 10];
int *p = new(buf) int[10];
-}
+} // { dg-prune-output "-Wfree-nonheap-object" }
/* Delete of placement new. */
void test_3 (void)
{
char buf[sizeof(int)]; // { dg-message "region created on stack here" }
- int *p = new(buf) int (42);
+ int *p = new (buf) int (42);
delete p; // { dg-warning "memory on the stack" }
}
// { dg-prune-output "-Wfree-nonheap-object" }
+
+void test_4 (void)
+{
+ int buf[5]; // { dg-message "region created on stack here" }
+ int *p = new (&buf[2]) int (42);
+ delete p; // { dg-warning "memory on the stack" }
+}
+
+
+// { dg-prune-output "-Wfree-nonheap-object" }
+
+void test_write_placement_after_delete (void)
+{
+ short *s = ::new short;
+ short *lp = ::new (s) short;
+ ::delete s;
+ *lp = 12; /* { dg-warning "use after 'delete' of 'lp'" "write placement new after buffer deletion" } */
+}
+
+void test_read_placement_after_delete (void)
+{
+ short *s = ::new short;
+ short *lp = ::new (s) short;
+ ::delete s;
+ short m = *lp; // { dg-warning "use after 'delete' of 'lp'" "read placement new after buffer deletion" }
+}
+
+struct A
+{
+ int x;
+ int y;
+};
+
+void test_use_placement_after_destruction (void)
+{
+ A a;
+ int *lp = ::new (&a.y) int;
+ *lp = 2; /* { dg-bogus "-Wanalyzer-use-of-uninitialized-value" } */
+ a.~A();
+ int m = *lp; /* { dg-warning "use of uninitialized value '\\*lp'" "use of placement after the underlying buffer was destructed." } */
+}
+
+void test_initialization_through_placement (void)
+{
+ int x;
+ int *p = ::new (&x) int;
+ *p = 10;
+ int z = x + 2; /* { dg-bogus "use of uninitialized value 'x'" "x has been initialized through placement pointer" } */
+}
+
+void test_partial_initialization_through_placement (void)
+{
+ char buf[4];
+ char *p = ::new (&buf[2]) char;
+ *p = 10;
+ char *y = ::new (&buf[0]) char;
+ char z = buf[2] + 2; /* { dg-bogus "use of uninitialized value" } */
+ z = *y + 2; /* { dg-warning "use of uninitialized value '\\*y'" "y has only been partially initialized" } */
+}
+
+
+void test_delete_placement (void)
+{
+ A *a = ::new A; /* { dg-bogus "use of possibly-NULL 'operator new(8)' where non-null expected" "throwing new cannot be null" } */
+ int *z = ::new (&a->y) int;
+ a->~A(); // deconstruct properly
+ ::operator delete (a);
+ ::operator delete (z); /* { dg-warning "use after 'delete' of 'z'" } */
+}
+
+void test_delete_placement_2 (void)
+{
+ A *a = ::new A; /* { dg-bogus "use of possibly-NULL 'operator new(8)' where non-null expected" "throwing new cannot be null" } */
+ int *z = ::new (&a->y) int;
+ delete a;
+ ::operator delete (z); /* { dg-warning "use after 'delete' of 'z'" } */
+}
+
+void test_use_placement_after_deallocation (void)
+{
+ A *a = ::new A ();
+ int *lp = ::new (&a->y) int;
+ *lp = 2; /* { dg-bogus "use of uninitialized value" } */
+ ::operator delete (a);
+ int m = *lp; /* { dg-warning "use after 'delete' of 'lp'" "use of placement after the underlying buffer was deallocated." } */
+}
projects / thirdparty / gcc.git / commitdiff
