Merge tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardening updates from Kees Cook:
 "As is pretty normal for this tree, there are changes all over the
  place, especially for small fixes, selftest improvements, and improved
  macro usability.

  Some header changes ended up landing via this tree as they depended on
  the string header cleanups. Also, a notable set of changes is the work
  for the reintroduction of the UBSAN signed integer overflow sanitizer
  so that we can continue to make improvements on the compiler side to
  make this sanitizer a more viable future security hardening option.

  Summary:

   - string.h and related header cleanups (Tanzir Hasan, Andy
     Shevchenko)

   - VMCI memcpy() usage and struct_size() cleanups (Vasiliy Kovalev,
     Harshit Mogalapalli)

   - selftests/powerpc: Fix load_unaligned_zeropad build failure
     (Michael Ellerman)

   - hardened Kconfig fragment updates (Marco Elver, Lukas Bulwahn)

   - Handle tail call optimization better in LKDTM (Douglas Anderson)

   - Use long form types in overflow.h (Andy Shevchenko)

   - Add flags param to string_get_size() (Andy Shevchenko)

   - Add Coccinelle script for potential struct_size() use (Jacob
     Keller)

   - Fix objtool corner case under KCFI (Josh Poimboeuf)

   - Drop 13 year old backward compat CAP_SYS_ADMIN check (Jingzi Meng)

   - Add str_plural() helper (Michal Wajdeczko, Kees Cook)

   - Ignore relocations in .notes section

   - Add comments to explain how __is_constexpr() works

   - Fix m68k stack alignment expectations in stackinit Kunit test

   - Convert string selftests to KUnit

   - Add KUnit tests for fortified string functions

   - Improve reporting during fortified string warnings

   - Allow non-type arg to type_max() and type_min()

   - Allow strscpy() to be called with only 2 arguments

   - Add binary mode to leaking_addresses scanner

   - Various small cleanups to leaking_addresses scanner

   - Adding wrapping_*() arithmetic helper

   - Annotate initial signed integer wrap-around in refcount_t

   - Add explicit UBSAN section to MAINTAINERS

   - Fix UBSAN self-test warnings

   - Simplify UBSAN build via removal of CONFIG_UBSAN_SANITIZE_ALL

   - Reintroduce UBSAN's signed overflow sanitizer"

* tag 'hardening-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (51 commits)
  selftests/powerpc: Fix load_unaligned_zeropad build failure
  string: Convert helpers selftest to KUnit
  string: Convert selftest to KUnit
  sh: Fix build with CONFIG_UBSAN=y
  compiler.h: Explain how __is_constexpr() works
  overflow: Allow non-type arg to type_max() and type_min()
  VMCI: Fix possible memcpy() run-time warning in vmci_datagram_invoke_guest_handler()
  lib/string_helpers: Add flags param to string_get_size()
  x86, relocs: Ignore relocations in .notes section
  objtool: Fix UNWIND_HINT_{SAVE,RESTORE} across basic blocks
  overflow: Use POD in check_shl_overflow()
  lib: stackinit: Adjust target string to 8 bytes for m68k
  sparc: vdso: Disable UBSAN instrumentation
  kernel.h: Move lib/cmdline.c prototypes to string.h
  leaking_addresses: Provide mechanism to scan binary files
  leaking_addresses: Ignore input device status lines
  leaking_addresses: Use File::Temp for /tmp files
  MAINTAINERS: Update LEAKING_ADDRESSES details
  fortify: Improve buffer overflow reporting
  fortify: Add KUnit tests for runtime overflows
  ...

1 files changed, 81 insertions, 5 deletions

diff --git a/include/linux/string.h b/include/linux/string.h
index 4795ee5c50c6..9ba8b4597009 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_STRING_H_
 #define _LINUX_STRING_H_
 
+#include <linux/args.h>
 #include <linux/array_size.h>
 #include <linux/compiler.h>	/* for inline */
 #include <linux/types.h>	/* for size_t */
@@ -66,12 +67,79 @@ extern char * strcpy(char *,const char *);
 #ifndef __HAVE_ARCH_STRNCPY
 extern char * strncpy(char *,const char *, __kernel_size_t);
 #endif
-#ifndef __HAVE_ARCH_STRSCPY
-ssize_t strscpy(char *, const char *, size_t);
-#endif
+ssize_t sized_strscpy(char *, const char *, size_t);
+
+/*
+ * The 2 argument style can only be used when dst is an array with a
+ * known size.
+ */
+#define __strscpy0(dst, src, ...)	\
+	sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst))
+#define __strscpy1(dst, src, size)	sized_strscpy(dst, src, size)
+
+#define __strscpy_pad0(dst, src, ...)	\
+	sized_strscpy_pad(dst, src, sizeof(dst) + __must_be_array(dst))
+#define __strscpy_pad1(dst, src, size)	sized_strscpy_pad(dst, src, size)
+
+/**
+ * strscpy - Copy a C-string into a sized buffer
+ * @dst: Where to copy the string to
+ * @src: Where to copy the string from
+ * @...: Size of destination buffer (optional)
+ *
+ * Copy the source string @src, or as much of it as fits, into the
+ * destination @dst buffer. The behavior is undefined if the string
+ * buffers overlap. The destination @dst buffer is always NUL terminated,
+ * unless it's zero-sized.
+ *
+ * The size argument @... is only required when @dst is not an array, or
+ * when the copy needs to be smaller than sizeof(@dst).
+ *
+ * Preferred to strncpy() since it always returns a valid string, and
+ * doesn't unnecessarily force the tail of the destination buffer to be
+ * zero padded. If padding is desired please use strscpy_pad().
+ *
+ * Returns the number of characters copied in @dst (not including the
+ * trailing %NUL) or -E2BIG if @size is 0 or the copy from @src was
+ * truncated.
+ */
+#define strscpy(dst, src, ...)	\
+	CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
+
+#define sized_strscpy_pad(dest, src, count)	({			\
+	char *__dst = (dest);						\
+	const char *__src = (src);					\
+	const size_t __count = (count);					\
+	ssize_t __wrote;						\
+									\
+	__wrote = sized_strscpy(__dst, __src, __count);			\
+	if (__wrote >= 0 && __wrote < __count)				\
+		memset(__dst + __wrote + 1, 0, __count - __wrote - 1);	\
+	__wrote;							\
+})
 
-/* Wraps calls to strscpy()/memset(), no arch specific code required */
-ssize_t strscpy_pad(char *dest, const char *src, size_t count);
+/**
+ * strscpy_pad() - Copy a C-string into a sized buffer
+ * @dst: Where to copy the string to
+ * @src: Where to copy the string from
+ * @...: Size of destination buffer
+ *
+ * Copy the string, or as much of it as fits, into the dest buffer. The
+ * behavior is undefined if the string buffers overlap. The destination
+ * buffer is always %NUL terminated, unless it's zero-sized.
+ *
+ * If the source string is shorter than the destination buffer, the
+ * remaining bytes in the buffer will be filled with %NUL bytes.
+ *
+ * For full explanation of why you may want to consider using the
+ * 'strscpy' functions please see the function docstring for strscpy().
+ *
+ * Returns:
+ * * The number of characters copied (not including the trailing %NULs)
+ * * -E2BIG if count is 0 or @src was truncated.
+ */
+#define strscpy_pad(dst, src, ...)	\
+	CONCATENATE(__strscpy_pad, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
 
 #ifndef __HAVE_ARCH_STRCAT
 extern char * strcat(char *, const char *);
@@ -219,9 +287,17 @@ extern void *kvmemdup(const void *src, size_t len, gfp_t gfp) __realloc_size(2);
 extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp);
 extern void *kmemdup_array(const void *src, size_t element_size, size_t count, gfp_t gfp);
 
+/* lib/argv_split.c */
 extern char **argv_split(gfp_t gfp, const char *str, int *argcp);
 extern void argv_free(char **argv);
 
+/* lib/cmdline.c */
+extern int get_option(char **str, int *pint);
+extern char *get_options(const char *str, int nints, int *ints);
+extern unsigned long long memparse(const char *ptr, char **retptr);
+extern bool parse_option_str(const char *str, const char *option);
+extern char *next_arg(char *args, char **param, char **val);
+
 extern bool sysfs_streq(const char *s1, const char *s2);
 int match_string(const char * const *array, size_t n, const char *string);
 int __sysfs_match_string(const char * const *array, size_t n, const char *s);