https://github.com/google/kmsan
Revision e6bc8833d80fb695515a8144aa1dc13468db9d4d authored by Alexander Potapenko on 27 February 2023, 15:44:58 UTC, committed by Alexander Potapenko on 19 June 2023, 08:56:03 UTC
lib/string.c is built with -ffreestanding, which prevents the compiler from replacing certain functions with calls to their library versions. On the other hand, this also prevents Clang and GCC from instrumenting calls to memcpy() when building with KASAN, KCSAN or KMSAN: - KASAN normally replaces memcpy() with __asan_memcpy() with the additional cc-param,asan-kernel-mem-intrinsic-prefix=1; - KCSAN and KMSAN replace memcpy() with __tsan_memcpy() and __msan_memcpy() by default. To let the tools catch memory accesses from strlcpy/strlcat, replace the calls to memcpy() with __builtin_memcpy(), which KASAN, KCSAN and KMSAN are able to replace even in -ffreestanding mode. This preserves the behavior in normal builds (__builtin_memcpy() ends up being replaced with memcpy()), and does not introduce new instrumentation in unwanted places, as strlcpy/strlcat are already instrumented. Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/all/20230224085942.1791837-1-elver@google.com/ Acked-by: Kees Cook <keescook@chromium.org>
1 parent 11aac78
Tip revision: e6bc8833d80fb695515a8144aa1dc13468db9d4d authored by Alexander Potapenko on 27 February 2023, 15:44:58 UTC
string: use __builtin_memcpy() in strlcpy/strlcat
string: use __builtin_memcpy() in strlcpy/strlcat
Tip revision: e6bc883
init-mm.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/mm_types.h>
#include <linux/maple_tree.h>
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/cpumask.h>
#include <linux/mman.h>
#include <linux/pgtable.h>
#include <linux/atomic.h>
#include <linux/user_namespace.h>
#include <linux/iommu.h>
#include <asm/mmu.h>
#ifndef INIT_MM_CONTEXT
#define INIT_MM_CONTEXT(name)
#endif
/*
* For dynamically allocated mm_structs, there is a dynamically sized cpumask
* at the end of the structure, the size of which depends on the maximum CPU
* number the system can see. That way we allocate only as much memory for
* mm_cpumask() as needed for the hundreds, or thousands of processes that
* a system typically runs.
*
* Since there is only one init_mm in the entire system, keep it simple
* and size this cpu_bitmask to NR_CPUS.
*/
struct mm_struct init_mm = {
.mm_mt = MTREE_INIT_EXT(mm_mt, MM_MT_FLAGS, init_mm.mmap_lock),
.pgd = swapper_pg_dir,
.mm_users = ATOMIC_INIT(2),
.mm_count = ATOMIC_INIT(1),
.write_protect_seq = SEQCNT_ZERO(init_mm.write_protect_seq),
MMAP_LOCK_INITIALIZER(init_mm)
.page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
.arg_lock = __SPIN_LOCK_UNLOCKED(init_mm.arg_lock),
.mmlist = LIST_HEAD_INIT(init_mm.mmlist),
#ifdef CONFIG_PER_VMA_LOCK
.mm_lock_seq = 0,
#endif
.user_ns = &init_user_ns,
.cpu_bitmap = CPU_BITS_NONE,
#ifdef CONFIG_IOMMU_SVA
.pasid = IOMMU_PASID_INVALID,
#endif
INIT_MM_CONTEXT(init_mm)
};
void setup_initial_init_mm(void *start_code, void *end_code,
void *end_data, void *brk)
{
init_mm.start_code = (unsigned long)start_code;
init_mm.end_code = (unsigned long)end_code;
init_mm.end_data = (unsigned long)end_data;
init_mm.brk = (unsigned long)brk;
}
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