asan: Add --param=asan-kernel-mem-intrinsic-prefix= [PR108777]

While in the -fsanitize=address case libasan overloads memcpy, memset,
memmove and many other builtins, such that they are always instrumented,
Linux kernel for -fsanitize=kernel-address recently changed or is changing,
such that memcpy, memset and memmove actually aren't instrumented because
they are often used also from no_sanitize ("kernel-address") functions
and wants __{,hw,}asaN_{memcpy,memset,memmove} to be used instead
for the instrumented calls.  See e.g. the https://lkml.org/lkml/2023/2/9/1182
thread.  Without appropriate support on the compiler side, that will mean
any time a kernel-address instrumented function (most of them) calls
memcpy/memset/memmove, they will not be instrumented and thus won't catch
kernel bugs.  Apparently clang 15 has a param for this.

The following patch implements the same (except it is a usual GCC --param,
not -mllvm argument) on the GCC side.  I know this isn't a regression
bugfix, but given that -fsanitize=kernel-address has a single project that
uses it which badly wants this I think it would be worthwhile to make an
exception and get this into GCC 13 rather than waiting another year, it
won't affect non-kernel code, nor even the kernel unless the new parameter
is used.

2023-02-14  Jakub Jelinek  <jakub@redhat.com>

	PR sanitizer/108777
	* params.opt (-param=asan-kernel-mem-intrinsic-prefix=): New param.
	* asan.h (asan_memfn_rtl): Declare.
	* asan.cc (asan_memfn_rtls): New variable.
	(asan_memfn_rtl): New function.
	* builtins.cc (expand_builtin): If
	param_asan_kernel_mem_intrinsic_prefix and function is
	kernel-{,hw}address sanitized, emit calls to
	__{,hw}asan_{memcpy,memmove,memset} rather than
	{memcpy,memmove,memset}.  Use sanitize_flags_p (SANITIZE_ADDRESS)
	instead of flag_sanitize & SANITIZE_ADDRESS to check if
	asan_intercepted_p functions shouldn't be expanded inline.

	* gcc.dg/asan/pr108777-1.c: New test.
	* gcc.dg/asan/pr108777-2.c: New test.
	* gcc.dg/asan/pr108777-3.c: New test.
	* gcc.dg/asan/pr108777-4.c: New test.
	* gcc.dg/asan/pr108777-5.c: New test.
	* gcc.dg/asan/pr108777-6.c: New test.
	* gcc.dg/completion-3.c: Adjust expected multiline output.

diff --git a/gcc/asan.cc b/gcc/asan.cc
index 57834b70dbae31b432905a8bbc095053e8359101..f56d084bc7ab5c311fdfd837d83051e4213c3935 100644 (file)
--- a/gcc/asan.cc
+++ b/gcc/asan.cc
@@ -391,6 +391,46 @@ asan_memintrin (void)
 }
 
 
+/* Support for --param asan-kernel-mem-intrinsic-prefix=1.  */
+static GTY(()) rtx asan_memfn_rtls[3];
+
+rtx
+asan_memfn_rtl (tree fndecl)
+{
+  int i;
+  const char *f, *p;
+  char buf[sizeof ("__hwasan_memmove")];
+
+  switch (DECL_FUNCTION_CODE (fndecl))
+    {
+    case BUILT_IN_MEMCPY: i = 0; f = "memcpy"; break;
+    case BUILT_IN_MEMSET: i = 1; f = "memset"; break;
+    case BUILT_IN_MEMMOVE: i = 2; f = "memmove"; break;
+    default: gcc_unreachable ();
+    }
+  if (asan_memfn_rtls[i] == NULL_RTX)
+    {
+      tree save_name = DECL_NAME (fndecl);
+      tree save_assembler_name = DECL_ASSEMBLER_NAME (fndecl);
+      rtx save_rtl = DECL_RTL (fndecl);
+      if (flag_sanitize & SANITIZE_KERNEL_HWADDRESS)
+       p = "__hwasan_";
+      else
+       p = "__asan_";
+      strcpy (buf, p);
+      strcat (buf, f);
+      DECL_NAME (fndecl) = get_identifier (buf);
+      DECL_ASSEMBLER_NAME_RAW (fndecl) = NULL_TREE;
+      SET_DECL_RTL (fndecl, NULL_RTX);
+      asan_memfn_rtls[i] = DECL_RTL (fndecl);
+      DECL_NAME (fndecl) = save_name;
+      DECL_ASSEMBLER_NAME_RAW (fndecl) = save_assembler_name;
+      SET_DECL_RTL (fndecl, save_rtl);
+    }
+  return asan_memfn_rtls[i];
+}
+
+
 /* Checks whether section SEC should be sanitized.  */
 
 static bool

diff --git a/gcc/asan.h b/gcc/asan.h
index 902e93b848a901ec1132c4eea10079f22a715e21..b049c8903a60cf59c042e1c075eac787ca4fb176 100644 (file)
--- a/gcc/asan.h
+++ b/gcc/asan.h
@@ -33,6 +33,7 @@ extern bool asan_expand_check_ifn (gimple_stmt_iterator *, bool);
 extern bool asan_expand_mark_ifn (gimple_stmt_iterator *);
 extern bool asan_expand_poison_ifn (gimple_stmt_iterator *, bool *,
                                    hash_map<tree, tree> &);
+extern rtx asan_memfn_rtl (tree);
 
 extern void hwasan_record_frame_init ();
 extern void hwasan_record_stack_var (rtx, rtx, poly_int64, poly_int64);

diff --git a/gcc/builtins.cc b/gcc/builtins.cc
index 8327bcb2c3a301a1b380143f54db6935e2e25318..4d467c8c5c10a5f86875fd0a3dbca435ec4e63c9 100644 (file)
--- a/gcc/builtins.cc
+++ b/gcc/builtins.cc
@@ -7326,7 +7326,24 @@ expand_builtin (tree exp, rtx target, rtx subtarget, machine_mode mode,
      by ASan.  */
 
   enum built_in_function fcode = DECL_FUNCTION_CODE (fndecl);
-  if ((flag_sanitize & SANITIZE_ADDRESS) && asan_intercepted_p (fcode))
+  if (param_asan_kernel_mem_intrinsic_prefix
+      && sanitize_flags_p (SANITIZE_KERNEL_ADDRESS
+                          | SANITIZE_KERNEL_HWADDRESS))
+    switch (fcode)
+      {
+       rtx save_decl_rtl, ret;
+      case BUILT_IN_MEMCPY:
+      case BUILT_IN_MEMMOVE:
+      case BUILT_IN_MEMSET:
+       save_decl_rtl = DECL_RTL (fndecl);
+       DECL_RTL (fndecl) = asan_memfn_rtl (fndecl);
+       ret = expand_call (exp, target, ignore);
+       DECL_RTL (fndecl) = save_decl_rtl;
+       return ret;
+      default:
+       break;
+      }
+  if (sanitize_flags_p (SANITIZE_ADDRESS) && asan_intercepted_p (fcode))
     return expand_call (exp, target, ignore);
 
   /* When not optimizing, generate calls to library functions for a certain

diff --git a/gcc/params.opt b/gcc/params.opt
index c7913d9063a66be5e970cc275e181d7091d15b69..41d8bef245ea358cde416be9e0a54d540f6f7660 100644 (file)
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -50,6 +50,10 @@ Enable asan store operations protection.
 Common Joined UInteger Var(param_asan_instrumentation_with_call_threshold) Init(7000) Param Optimization
 Use callbacks instead of inline code if number of accesses in function becomes greater or equal to this number.
 
+-param=asan-kernel-mem-intrinsic-prefix=
+Common Joined UInteger Var(param_asan_kernel_mem_intrinsic_prefix) Init(0) IntegerRange(0, 1) Param Optimization
+Prefix calls to memcpy, memset and memmove with __asan_ or __hwasan_ for -fsanitize=kernel-address or -fsanitize=kernel-hwaddress.
+
 -param=asan-memintrin=
 Common Joined UInteger Var(param_asan_memintrin) Init(1) IntegerRange(0, 1) Param Optimization
 Enable asan builtin functions protection.

diff --git a/gcc/testsuite/gcc.dg/asan/pr108777-1.c b/gcc/testsuite/gcc.dg/asan/pr108777-1.c
new file mode 100644 (file)
index 0000000..2cf4c52
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr108777-1.c
@@ -0,0 +1,28 @@
+/* PR sanitizer/108777 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-sanitize=all -fsanitize=kernel-address --param asan-kernel-mem-intrinsic-prefix=1" } */
+/* { dg-final { scan-assembler "__asan_memcpy" } } */
+/* { dg-final { scan-assembler "__asan_memset" } } */
+/* { dg-final { scan-assembler "__asan_memmove" } } */
+
+extern void *memcpy (void *, const void *, __SIZE_TYPE__);
+extern void *memmove (void *, const void *, __SIZE_TYPE__);
+extern void *memset (void *, int, __SIZE_TYPE__);
+
+void
+foo (void *p, void *q, int s)
+{
+  memcpy (p, q, s);
+}
+
+void
+bar (void *p, void *q, int s)
+{
+  memmove (p, q, s);
+}
+
+void
+baz (void *p, int c, int s)
+{
+  memset (p, c, s);
+}

diff --git a/gcc/testsuite/gcc.dg/asan/pr108777-2.c b/gcc/testsuite/gcc.dg/asan/pr108777-2.c
new file mode 100644 (file)
index 0000000..e944b63
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr108777-2.c
@@ -0,0 +1,24 @@
+/* PR sanitizer/108777 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-sanitize=all -fsanitize=kernel-address --param asan-kernel-mem-intrinsic-prefix=1" } */
+/* { dg-final { scan-assembler "__asan_memcpy" } } */
+/* { dg-final { scan-assembler "__asan_memset" } } */
+/* { dg-final { scan-assembler "__asan_memmove" } } */
+
+void
+foo (void *p, void *q, int s)
+{
+  __builtin_memcpy (p, q, s);
+}
+
+void
+bar (void *p, void *q, int s)
+{
+  __builtin_memmove (p, q, s);
+}
+
+void
+baz (void *p, int c, int s)
+{
+  __builtin_memset (p, c, s);
+}

diff --git a/gcc/testsuite/gcc.dg/asan/pr108777-3.c b/gcc/testsuite/gcc.dg/asan/pr108777-3.c
new file mode 100644 (file)
index 0000000..11d3ef3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr108777-3.c
@@ -0,0 +1,28 @@
+/* PR sanitizer/108777 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-sanitize=all -fsanitize=kernel-address --param asan-kernel-mem-intrinsic-prefix=1" } */
+/* { dg-final { scan-assembler-not "__asan_memcpy" } } */
+/* { dg-final { scan-assembler-not "__asan_memset" } } */
+/* { dg-final { scan-assembler-not "__asan_memmove" } } */
+
+extern void *memcpy (void *, const void *, __SIZE_TYPE__);
+extern void *memmove (void *, const void *, __SIZE_TYPE__);
+extern void *memset (void *, int, __SIZE_TYPE__);
+
+__attribute__((no_sanitize("kernel-address"))) void
+foo (void *p, void *q, int s)
+{
+  memcpy (p, q, s);
+}
+
+__attribute__((no_sanitize("kernel-address"))) void
+bar (void *p, void *q, int s)
+{
+  memmove (p, q, s);
+}
+
+__attribute__((no_sanitize("kernel-address"))) void
+baz (void *p, int c, int s)
+{
+  memset (p, c, s);
+}

diff --git a/gcc/testsuite/gcc.dg/asan/pr108777-4.c b/gcc/testsuite/gcc.dg/asan/pr108777-4.c
new file mode 100644 (file)
index 0000000..804924c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr108777-4.c
@@ -0,0 +1,24 @@
+/* PR sanitizer/108777 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-sanitize=all -fsanitize=kernel-address --param asan-kernel-mem-intrinsic-prefix=1" } */
+/* { dg-final { scan-assembler-not "__asan_memcpy" } } */
+/* { dg-final { scan-assembler-not "__asan_memset" } } */
+/* { dg-final { scan-assembler-not "__asan_memmove" } } */
+
+__attribute__((no_sanitize("kernel-address"))) void
+foo (void *p, void *q, int s)
+{
+  __builtin_memcpy (p, q, s);
+}
+
+__attribute__((no_sanitize("kernel-address"))) void
+bar (void *p, void *q, int s)
+{
+  __builtin_memmove (p, q, s);
+}
+
+__attribute__((no_sanitize("kernel-address"))) void
+baz (void *p, int c, int s)
+{
+  __builtin_memset (p, c, s);
+}

diff --git a/gcc/testsuite/gcc.dg/asan/pr108777-5.c b/gcc/testsuite/gcc.dg/asan/pr108777-5.c
new file mode 100644 (file)
index 0000000..83d44a7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr108777-5.c
@@ -0,0 +1,28 @@
+/* PR sanitizer/108777 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-sanitize=all -fsanitize=kernel-address" } */
+/* { dg-final { scan-assembler-not "__asan_memcpy" } } */
+/* { dg-final { scan-assembler-not "__asan_memset" } } */
+/* { dg-final { scan-assembler-not "__asan_memmove" } } */
+
+extern void *memcpy (void *, const void *, __SIZE_TYPE__);
+extern void *memmove (void *, const void *, __SIZE_TYPE__);
+extern void *memset (void *, int, __SIZE_TYPE__);
+
+void
+foo (void *p, void *q, int s)
+{
+  memcpy (p, q, s);
+}
+
+void
+bar (void *p, void *q, int s)
+{
+  memmove (p, q, s);
+}
+
+void
+baz (void *p, int c, int s)
+{
+  memset (p, c, s);
+}

diff --git a/gcc/testsuite/gcc.dg/asan/pr108777-6.c b/gcc/testsuite/gcc.dg/asan/pr108777-6.c
new file mode 100644 (file)
index 0000000..dc07818
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr108777-6.c
@@ -0,0 +1,24 @@
+/* PR sanitizer/108777 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-sanitize=all -fsanitize=kernel-address" } */
+/* { dg-final { scan-assembler-not "__asan_memcpy" } } */
+/* { dg-final { scan-assembler-not "__asan_memset" } } */
+/* { dg-final { scan-assembler-not "__asan_memmove" } } */
+
+void
+foo (void *p, void *q, int s)
+{
+  __builtin_memcpy (p, q, s);
+}
+
+void
+bar (void *p, void *q, int s)
+{
+  __builtin_memmove (p, q, s);
+}
+
+void
+baz (void *p, int c, int s)
+{
+  __builtin_memset (p, c, s);
+}

diff --git a/gcc/testsuite/gcc.dg/completion-3.c b/gcc/testsuite/gcc.dg/completion-3.c
index a240993dd45e3d162ad9ed95118cb2faba16b22e..462d356250fb3bb98388e1385572563658e24088 100644 (file)
--- a/gcc/testsuite/gcc.dg/completion-3.c
+++ b/gcc/testsuite/gcc.dg/completion-3.c
@@ -7,6 +7,7 @@
 --param=asan-instrument-reads=
 --param=asan-instrument-writes=
 --param=asan-instrumentation-with-call-threshold=
+--param=asan-kernel-mem-intrinsic-prefix=
 --param=asan-memintrin=
 --param=asan-stack=
 --param=asan-use-after-return=