Merge branch 'for-5.12-no_hash_pointers' into for-linus (2a8c3a64) · Commits · EulixOS / Software / Kernel

Documentation/admin-guide/kernel-parameters.txt

+15 −0

Original line number	Diff line number	Diff line
		@@ -3281,6 +3281,21 @@
		in certain environments such as networked servers or
		real-time systems.

		no_hash_pointers
		Force pointers printed to the console or buffers to be
		unhashed. By default, when a pointer is printed via %p
		format string, that pointer is "hashed", i.e. obscured
		by hashing the pointer value. This is a security feature
		that hides actual kernel addresses from unprivileged
		users, but it also makes debugging the kernel more
		difficult since unequal pointers can no longer be
		compared. However, if this command-line option is
		specified, then all normal pointers will have their true
		value printed. Pointers printed via %pK may still be
		hashed. This option should only be specified when
		debugging the kernel. Please do not use on production
		kernels.

		nohibernate [HIBERNATION] Disable hibernation and resume.

		nohz= [KNL] Boottime enable/disable dynamic ticks

lib/test_bitmap.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -16,8 +16,7 @@

		#include "../tools/testing/selftests/kselftest_module.h"

		static unsigned total_tests __initdata;
		static unsigned failed_tests __initdata;
		KSTM_MODULE_GLOBALS();

		static char pbl_buffer[PAGE_SIZE] __initdata;

lib/test_printf.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -30,11 +30,13 @@
		#define PAD_SIZE 16
		#define FILL_CHAR '$'

		static unsigned total_tests __initdata;
		static unsigned failed_tests __initdata;
		KSTM_MODULE_GLOBALS();

		static char *test_buffer __initdata;
		static char *alloced_buffer __initdata;

		extern bool no_hash_pointers;

		static int __printf(4, 0) __init
		do_test(int bufsize, const char *expect, int elen,
		const char *fmt, va_list ap)
		@@ -301,6 +303,12 @@ plain(void)
		{
		int err;

		if (no_hash_pointers) {
		pr_warn("skipping plain 'p' tests");
		skipped_tests += 2;
		return;
		}

		err = plain_hash();
		if (err) {
		pr_warn("plain 'p' does not appear to be hashed\n");

lib/vsprintf.c

+34 −2

Original line number	Diff line number	Diff line
		@@ -2090,6 +2090,32 @@ char fwnode_string(char buf, char end, struct fwnode_handle fwnode,
		return widen_string(buf, buf - buf_start, end, spec);
		}

		/* Disable pointer hashing if requested */
		bool no_hash_pointers __ro_after_init;
		EXPORT_SYMBOL_GPL(no_hash_pointers);

		static int __init no_hash_pointers_enable(char *str)
		{
		no_hash_pointers = true;

		pr_warn("**********************************************************\n");
		pr_warn(" NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE \n");
		pr_warn(" \n");
		pr_warn(" This system shows unhashed kernel memory addresses \n");
		pr_warn(" via the console, logs, and other interfaces. This \n");
		pr_warn(" might reduce the security of your system. \n");
		pr_warn(" \n");
		pr_warn(" If you see this message and you are not debugging \n");
		pr_warn(" the kernel, report this immediately to your system \n");
		pr_warn(" administrator! \n");
		pr_warn(" \n");
		pr_warn(" NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE \n");
		pr_warn("**********************************************************\n");

		return 0;
		}
		early_param("no_hash_pointers", no_hash_pointers_enable);

		/*
		* Show a '%p' thing. A kernel extension is that the '%p' is followed
		* by an extra set of alphanumeric characters that are extended format
		@@ -2297,7 +2323,13 @@ char pointer(const char fmt, char buf, char end, void *ptr,
		}
		}

		/* default is to _not_ leak addresses, hash before printing */
		/*
		* default is to _not_ leak addresses, so hash before printing,
		* unless no_hash_pointers is specified on the command line.
		*/
		if (unlikely(no_hash_pointers))
		return pointer_string(buf, end, ptr, spec);
		else
		return ptr_to_id(buf, end, ptr, spec);
		}

tools/testing/selftests/kselftest_module.h

+12 −6

Original line number	Diff line number	Diff line
		@@ -11,7 +11,8 @@

		#define KSTM_MODULE_GLOBALS() \
		static unsigned int total_tests __initdata; \
		static unsigned int failed_tests __initdata
		static unsigned int failed_tests __initdata; \
		static unsigned int skipped_tests __initdata

		#define KSTM_CHECK_ZERO(x) do { \
		total_tests++; \
		@@ -21,11 +22,16 @@ static unsigned int failed_tests __initdata
		} \
		} while (0)

		static inline int kstm_report(unsigned int total_tests, unsigned int failed_tests)
		static inline int kstm_report(unsigned int total_tests, unsigned int failed_tests,
		unsigned int skipped_tests)
		{
		if (failed_tests == 0)
		if (failed_tests == 0) {
		if (skipped_tests) {
		pr_info("skipped %u tests\n", skipped_tests);
		pr_info("remaining %u tests passed\n", total_tests);
		} else
		pr_info("all %u tests passed\n", total_tests);
		else
		} else
		pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);

		return failed_tests ? -EINVAL : 0;
		@@ -36,7 +42,7 @@ static int __init __module##_init(void) \
		{ \
		pr_info("loaded.\n"); \
		selftest(); \
		return kstm_report(total_tests, failed_tests); \
		return kstm_report(total_tests, failed_tests, skipped_tests); \
		} \
		static void __exit __module##_exit(void) \
		{ \