Commit 51094a24 authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'hardening-v6.2-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull kernel hardening fixes from Kees Cook:

 - Fix CFI failure with KASAN (Sami Tolvanen)

 - Fix LKDTM + CFI under GCC 7 and 8 (Kristina Martsenko)

 - Limit CONFIG_ZERO_CALL_USED_REGS to Clang > 15.0.6 (Nathan
   Chancellor)

 - Ignore "contents" argument in LoadPin's LSM hook handling

 - Fix paste-o in /sys/kernel/warn_count API docs

 - Use READ_ONCE() consistently for oops/warn limit reading

* tag 'hardening-v6.2-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  cfi: Fix CFI failure with KASAN
  exit: Use READ_ONCE() for all oops/warn limit reads
  security: Restrict CONFIG_ZERO_CALL_USED_REGS to gcc or clang > 15.0.6
  lkdtm: cfi: Make PAC test work with GCC 7 and 8
  docs: Fix path paste-o for /sys/kernel/warn_count
  LoadPin: Ignore the "contents" argument of the LSM hooks
parents edb23125 cf801640
What: /sys/kernel/oops_count
What: /sys/kernel/warn_count
Date: November 2022
KernelVersion: 6.2.0
Contact: Linux Kernel Hardening List <linux-hardening@vger.kernel.org>
......
......@@ -54,7 +54,11 @@ static void lkdtm_CFI_FORWARD_PROTO(void)
# ifdef CONFIG_ARM64_BTI_KERNEL
# define __no_pac "branch-protection=bti"
# else
# define __no_pac "branch-protection=none"
# ifdef CONFIG_CC_HAS_BRANCH_PROT_PAC_RET
# define __no_pac "branch-protection=none"
# else
# define __no_pac "sign-return-address=none"
# endif
# endif
# define __no_ret_protection __noscs __attribute__((__target__(__no_pac)))
#else
......
......@@ -41,9 +41,6 @@ UBSAN_SANITIZE_kcov.o := n
KMSAN_SANITIZE_kcov.o := n
CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector
# Don't instrument error handlers
CFLAGS_REMOVE_cfi.o := $(CC_FLAGS_CFI)
obj-y += sched/
obj-y += locking/
obj-y += power/
......
......@@ -931,6 +931,7 @@ void __noreturn make_task_dead(int signr)
* Then do everything else.
*/
struct task_struct *tsk = current;
unsigned int limit;
if (unlikely(in_interrupt()))
panic("Aiee, killing interrupt handler!");
......@@ -954,8 +955,9 @@ void __noreturn make_task_dead(int signr)
* To make sure this can't happen, place an upper bound on how often the
* kernel may oops without panic().
*/
if (atomic_inc_return(&oops_count) >= READ_ONCE(oops_limit) && oops_limit)
panic("Oopsed too often (kernel.oops_limit is %d)", oops_limit);
limit = READ_ONCE(oops_limit);
if (atomic_inc_return(&oops_count) >= limit && limit)
panic("Oopsed too often (kernel.oops_limit is %d)", limit);
/*
* We're taking recursive faults here in make_task_dead. Safest is to just
......
......@@ -232,12 +232,15 @@ static void panic_print_sys_info(bool console_flush)
void check_panic_on_warn(const char *origin)
{
unsigned int limit;
if (panic_on_warn)
panic("%s: panic_on_warn set ...\n", origin);
if (atomic_inc_return(&warn_count) >= READ_ONCE(warn_limit) && warn_limit)
limit = READ_ONCE(warn_limit);
if (atomic_inc_return(&warn_count) >= limit && limit)
panic("%s: system warned too often (kernel.warn_limit is %d)",
origin, warn_limit);
origin, limit);
}
/**
......
......@@ -257,6 +257,9 @@ config INIT_ON_FREE_DEFAULT_ON
config CC_HAS_ZERO_CALL_USED_REGS
def_bool $(cc-option,-fzero-call-used-regs=used-gpr)
# https://github.com/ClangBuiltLinux/linux/issues/1766
# https://github.com/llvm/llvm-project/issues/59242
depends on !CC_IS_CLANG || CLANG_VERSION > 150006
config ZERO_CALL_USED_REGS
bool "Enable register zeroing on function exit"
......
......@@ -122,21 +122,11 @@ static void loadpin_sb_free_security(struct super_block *mnt_sb)
}
}
static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
bool contents)
static int loadpin_check(struct file *file, enum kernel_read_file_id id)
{
struct super_block *load_root;
const char *origin = kernel_read_file_id_str(id);
/*
* If we will not know that we'll be seeing the full contents
* then we cannot trust a load will be complete and unchanged
* off disk. Treat all contents=false hooks as if there were
* no associated file struct.
*/
if (!contents)
file = NULL;
/* If the file id is excluded, ignore the pinning. */
if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
ignore_read_file_id[id]) {
......@@ -192,9 +182,25 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
return 0;
}
static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
bool contents)
{
/*
* LoadPin only cares about the _origin_ of a file, not its
* contents, so we can ignore the "are full contents available"
* argument here.
*/
return loadpin_check(file, id);
}
static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
{
return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents);
/*
* LoadPin only cares about the _origin_ of a file, not its
* contents, so a NULL file is passed, and we can ignore the
* state of "contents".
*/
return loadpin_check(NULL, (enum kernel_read_file_id) id);
}
static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
......
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