stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth

The Clang stack depth tracking implementation has a fixed name for
the stack depth tracking callback, "__sanitizer_cov_stack_depth", so
rename the GCC plugin function to match since the plugin has no external
dependencies on naming.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Kees Cook <[email protected]>

Author: kees

include/linux/kstack_erase.h

@@ -80,7 +80,7 @@ static inline void stackleak_task_init(struct task_struct *t)
 asmlinkage void noinstr stackleak_erase(void);
 asmlinkage void noinstr stackleak_erase_on_task_stack(void);
 asmlinkage void noinstr stackleak_erase_off_task_stack(void);
-void __no_caller_saved_registers noinstr stackleak_track_stack(void);
+void __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void);
 
 #else /* !CONFIG_KSTACK_ERASE */
 static inline void stackleak_task_init(struct task_struct *t) { }

kernel/kstack_erase.c

@@ -156,7 +156,7 @@ asmlinkage void noinstr stackleak_erase_off_task_stack(void)
 	__stackleak_erase(false);
 }
 
-void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
+void __used __no_caller_saved_registers noinstr __sanitizer_cov_stack_depth(void)
 {
 	unsigned long sp = current_stack_pointer;
 
@@ -174,4 +174,4 @@ void __used __no_caller_saved_registers noinstr stackleak_track_stack(void)
 		current->lowest_stack = sp;
 	}
 }
-EXPORT_SYMBOL(stackleak_track_stack);
+EXPORT_SYMBOL(__sanitizer_cov_stack_depth);

scripts/gcc-plugins/stackleak_plugin.c

@@ -9,7 +9,7 @@
  * any of the gcc libraries
  *
  * This gcc plugin is needed for tracking the lowest border of the kernel stack.
- * It instruments the kernel code inserting stackleak_track_stack() calls:
+ * It instruments the kernel code inserting __sanitizer_cov_stack_depth() calls:
  *  - after alloca();
  *  - for the functions with a stack frame size greater than or equal
  *     to the "track-min-size" plugin parameter.
@@ -33,7 +33,7 @@ __visible int plugin_is_GPL_compatible;
 
 static int track_frame_size = -1;
 static bool build_for_x86 = false;
-static const char track_function[] = "stackleak_track_stack";
+static const char track_function[] = "__sanitizer_cov_stack_depth";
 static bool disable = false;
 static bool verbose = false;
 
@@ -58,7 +58,7 @@ static void add_stack_tracking_gcall(gimple_stmt_iterator *gsi, bool after)
 	cgraph_node_ptr node;
 	basic_block bb;
 
-	/* Insert calling stackleak_track_stack() */
+	/* Insert calling __sanitizer_cov_stack_depth() */
 	stmt = gimple_build_call(track_function_decl, 0);
 	gimple_call = as_a_gcall(stmt);
 	if (after)
@@ -120,12 +120,12 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after)
 	gcc_assert(build_for_x86);
 
 	/*
-	 * Insert calling stackleak_track_stack() in asm:
-	 *   asm volatile("call stackleak_track_stack"
+	 * Insert calling __sanitizer_cov_stack_depth() in asm:
+	 *   asm volatile("call __sanitizer_cov_stack_depth"
 	 *		  :: "r" (current_stack_pointer))
 	 * Use ASM_CALL_CONSTRAINT trick from arch/x86/include/asm/asm.h.
 	 * This constraint is taken into account during gcc shrink-wrapping
-	 * optimization. It is needed to be sure that stackleak_track_stack()
+	 * optimization. It is needed to be sure that __sanitizer_cov_stack_depth()
 	 * call is inserted after the prologue of the containing function,
 	 * when the stack frame is prepared.
 	 */
@@ -137,7 +137,7 @@ static void add_stack_tracking_gasm(gimple_stmt_iterator *gsi, bool after)
 	input = build_tree_list(NULL_TREE, build_const_char_string(2, "r"));
 	input = chainon(NULL_TREE, build_tree_list(input, sp_decl));
 	vec_safe_push(inputs, input);
-	asm_call = gimple_build_asm_vec("call stackleak_track_stack",
+	asm_call = gimple_build_asm_vec("call __sanitizer_cov_stack_depth",
 					inputs, NULL, NULL, NULL);
 	gimple_asm_set_volatile(asm_call, true);
 	if (after)
@@ -151,11 +151,11 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after)
 {
 	/*
 	 * The 'no_caller_saved_registers' attribute is used for
-	 * stackleak_track_stack(). If the compiler supports this attribute for
-	 * the target arch, we can add calling stackleak_track_stack() in asm.
+	 * __sanitizer_cov_stack_depth(). If the compiler supports this attribute for
+	 * the target arch, we can add calling __sanitizer_cov_stack_depth() in asm.
 	 * That improves performance: we avoid useless operations with the
 	 * caller-saved registers in the functions from which we will remove
-	 * stackleak_track_stack() call during the stackleak_cleanup pass.
+	 * __sanitizer_cov_stack_depth() call during the stackleak_cleanup pass.
 	 */
 	if (lookup_attribute_spec(get_identifier("no_caller_saved_registers")))
 		add_stack_tracking_gasm(gsi, after);
@@ -165,7 +165,7 @@ static void add_stack_tracking(gimple_stmt_iterator *gsi, bool after)
 
 /*
  * Work with the GIMPLE representation of the code. Insert the
- * stackleak_track_stack() call after alloca() and into the beginning
+ * __sanitizer_cov_stack_depth() call after alloca() and into the beginning
  * of the function if it is not instrumented.
  */
 static unsigned int stackleak_instrument_execute(void)
@@ -205,7 +205,7 @@ static unsigned int stackleak_instrument_execute(void)
 					DECL_NAME_POINTER(current_function_decl));
 			}
 
-			/* Insert stackleak_track_stack() call after alloca() */
+			/* Insert __sanitizer_cov_stack_depth() call after alloca() */
 			add_stack_tracking(&gsi, true);
 			if (bb == entry_bb)
 				prologue_instrumented = true;
@@ -241,7 +241,7 @@ static unsigned int stackleak_instrument_execute(void)
 		return 0;
 	}
 
-	/* Insert stackleak_track_stack() call at the function beginning */
+	/* Insert __sanitizer_cov_stack_depth() call at the function beginning */
 	bb = entry_bb;
 	if (!single_pred_p(bb)) {
 		/* gcc_assert(bb_loop_depth(bb) ||
@@ -270,15 +270,15 @@ static void remove_stack_tracking_gcall(void)
 	rtx_insn *insn, *next;
 
 	/*
-	 * Find stackleak_track_stack() calls. Loop through the chain of insns,
+	 * Find __sanitizer_cov_stack_depth() calls. Loop through the chain of insns,
 	 * which is an RTL representation of the code for a function.
 	 *
 	 * The example of a matching insn:
-	 *  (call_insn 8 4 10 2 (call (mem (symbol_ref ("stackleak_track_stack")
-	 *  [flags 0x41] <function_decl 0x7f7cd3302a80 stackleak_track_stack>)
-	 *  [0 stackleak_track_stack S1 A8]) (0)) 675 {*call} (expr_list
-	 *  (symbol_ref ("stackleak_track_stack") [flags 0x41] <function_decl
-	 *  0x7f7cd3302a80 stackleak_track_stack>) (expr_list (0) (nil))) (nil))
+	 *  (call_insn 8 4 10 2 (call (mem (symbol_ref ("__sanitizer_cov_stack_depth")
+	 *  [flags 0x41] <function_decl 0x7f7cd3302a80 __sanitizer_cov_stack_depth>)
+	 *  [0 __sanitizer_cov_stack_depth S1 A8]) (0)) 675 {*call} (expr_list
+	 *  (symbol_ref ("__sanitizer_cov_stack_depth") [flags 0x41] <function_decl
+	 *  0x7f7cd3302a80 __sanitizer_cov_stack_depth>) (expr_list (0) (nil))) (nil))
 	 */
 	for (insn = get_insns(); insn; insn = next) {
 		rtx body;
@@ -318,7 +318,7 @@ static void remove_stack_tracking_gcall(void)
 		if (SYMBOL_REF_DECL(body) != track_function_decl)
 			continue;
 
-		/* Delete the stackleak_track_stack() call */
+		/* Delete the __sanitizer_cov_stack_depth() call */
 		delete_insn_and_edges(insn);
 #if BUILDING_GCC_VERSION < 8000
 		if (GET_CODE(next) == NOTE &&
@@ -340,12 +340,12 @@ static bool remove_stack_tracking_gasm(void)
 	gcc_assert(build_for_x86);
 
 	/*
-	 * Find stackleak_track_stack() asm calls. Loop through the chain of
+	 * Find __sanitizer_cov_stack_depth() asm calls. Loop through the chain of
 	 * insns, which is an RTL representation of the code for a function.
 	 *
 	 * The example of a matching insn:
 	 *  (insn 11 5 12 2 (parallel [ (asm_operands/v
-	 *  ("call stackleak_track_stack") ("") 0
+	 *  ("call __sanitizer_cov_stack_depth") ("") 0
 	 *  [ (reg/v:DI 7 sp [ current_stack_pointer ]) ]
 	 *  [ (asm_input:DI ("r")) ] [])
 	 *  (clobber (reg:CC 17 flags)) ]) -1 (nil))
@@ -375,7 +375,7 @@ static bool remove_stack_tracking_gasm(void)
 			continue;
 
 		if (strcmp(ASM_OPERANDS_TEMPLATE(body),
-						"call stackleak_track_stack")) {
+						"call __sanitizer_cov_stack_depth")) {
 			continue;
 		}
 
@@ -389,7 +389,7 @@ static bool remove_stack_tracking_gasm(void)
 
 /*
  * Work with the RTL representation of the code.
- * Remove the unneeded stackleak_track_stack() calls from the functions
+ * Remove the unneeded __sanitizer_cov_stack_depth() calls from the functions
  * which don't call alloca() and don't have a large enough stack frame size.
  */
 static unsigned int stackleak_cleanup_execute(void)
@@ -474,13 +474,13 @@ static bool stackleak_gate(void)
 	return track_frame_size >= 0;
 }
 
-/* Build the function declaration for stackleak_track_stack() */
+/* Build the function declaration for __sanitizer_cov_stack_depth() */
 static void stackleak_start_unit(void *gcc_data __unused,
 				 void *user_data __unused)
 {
 	tree fntype;
 
-	/* void stackleak_track_stack(void) */
+	/* void __sanitizer_cov_stack_depth(void) */
 	fntype = build_function_type_list(void_type_node, NULL_TREE);
 	track_function_decl = build_fn_decl(track_function, fntype);
 	DECL_ASSEMBLER_NAME(track_function_decl); /* for LTO */

security/Kconfig.hardening

@@ -129,8 +129,8 @@ config KSTACK_ERASE_TRACK_MIN_SIZE
 	help
 	  The KSTACK_ERASE option instruments the kernel code for tracking
 	  the lowest border of the kernel stack (and for some other purposes).
-	  It inserts the stackleak_track_stack() call for the functions with
-	  a stack frame size greater than or equal to this parameter.
+	  It inserts the __sanitizer_cov_stack_depth() call for the functions
+	  with a stack frame size greater than or equal to this parameter.
 	  If unsure, leave the default value 100.
 
 config KSTACK_ERASE_METRICS

tools/objtool/check.c

@@ -1193,7 +1193,7 @@ static const char *uaccess_safe_builtin[] = {
 	"__ubsan_handle_shift_out_of_bounds",
 	"__ubsan_handle_load_invalid_value",
 	/* KSTACK_ERASE */
-	"stackleak_track_stack",
+	"__sanitizer_cov_stack_depth",
 	/* TRACE_BRANCH_PROFILING */
 	"ftrace_likely_update",
 	/* STACKPROTECTOR */