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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-14 23:20:00 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-14 23:20:00 +0300
commit48ea09cddae0b794cde2070f106ef676703dbcd3 (patch)
treed4b76e71ee11468d8a83c852ebdf1405fae73927 /mm/slab_common.c
parentad76bf1ff18e059d64b70047940d298641d4cc2f (diff)
parentd272e01fa0a2f15c5c331a37cd99c6875c7b7186 (diff)
downloadlinux-48ea09cddae0b794cde2070f106ef676703dbcd3.tar.xz
Merge tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull kernel hardening updates from Kees Cook: - Convert flexible array members, fix -Wstringop-overflow warnings, and fix KCFI function type mismatches that went ignored by maintainers (Gustavo A. R. Silva, Nathan Chancellor, Kees Cook) - Remove the remaining side-effect users of ksize() by converting dma-buf, btrfs, and coredump to using kmalloc_size_roundup(), add more __alloc_size attributes, and introduce full testing of all allocator functions. Finally remove the ksize() side-effect so that each allocation-aware checker can finally behave without exceptions - Introduce oops_limit (default 10,000) and warn_limit (default off) to provide greater granularity of control for panic_on_oops and panic_on_warn (Jann Horn, Kees Cook) - Introduce overflows_type() and castable_to_type() helpers for cleaner overflow checking - Improve code generation for strscpy() and update str*() kern-doc - Convert strscpy and sigphash tests to KUnit, and expand memcpy tests - Always use a non-NULL argument for prepare_kernel_cred() - Disable structleak plugin in FORTIFY KUnit test (Anders Roxell) - Adjust orphan linker section checking to respect CONFIG_WERROR (Xin Li) - Make sure siginfo is cleared for forced SIGKILL (haifeng.xu) - Fix um vs FORTIFY warnings for always-NULL arguments * tag 'hardening-v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (31 commits) ksmbd: replace one-element arrays with flexible-array members hpet: Replace one-element array with flexible-array member um: virt-pci: Avoid GCC non-NULL warning signal: Initialize the info in ksignal lib: fortify_kunit: build without structleak plugin panic: Expose "warn_count" to sysfs panic: Introduce warn_limit panic: Consolidate open-coded panic_on_warn checks exit: Allow oops_limit to be disabled exit: Expose "oops_count" to sysfs exit: Put an upper limit on how often we can oops panic: Separate sysctl logic from CONFIG_SMP mm/pgtable: Fix multiple -Wstringop-overflow warnings mm: Make ksize() a reporting-only function kunit/fortify: Validate __alloc_size attribute results drm/sti: Fix return type of sti_{dvo,hda,hdmi}_connector_mode_valid() drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid() driver core: Add __alloc_size hint to devm allocators overflow: Introduce overflows_type() and castable_to_type() coredump: Proactively round up to kmalloc bucket size ...
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c26
1 files changed, 10 insertions, 16 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 3e49bb830060..1cba98acc486 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1348,11 +1348,11 @@ __do_krealloc(const void *p, size_t new_size, gfp_t flags)
void *ret;
size_t ks;
- /* Don't use instrumented ksize to allow precise KASAN poisoning. */
+ /* Check for double-free before calling ksize. */
if (likely(!ZERO_OR_NULL_PTR(p))) {
if (!kasan_check_byte(p))
return NULL;
- ks = kfence_ksize(p) ?: __ksize(p);
+ ks = ksize(p);
} else
ks = 0;
@@ -1420,21 +1420,21 @@ void kfree_sensitive(const void *p)
void *mem = (void *)p;
ks = ksize(mem);
- if (ks)
+ if (ks) {
+ kasan_unpoison_range(mem, ks);
memzero_explicit(mem, ks);
+ }
kfree(mem);
}
EXPORT_SYMBOL(kfree_sensitive);
size_t ksize(const void *objp)
{
- size_t size;
-
/*
- * We need to first check that the pointer to the object is valid, and
- * only then unpoison the memory. The report printed from ksize() is
- * more useful, then when it's printed later when the behaviour could
- * be undefined due to a potential use-after-free or double-free.
+ * We need to first check that the pointer to the object is valid.
+ * The KASAN report printed from ksize() is more useful, then when
+ * it's printed later when the behaviour could be undefined due to
+ * a potential use-after-free or double-free.
*
* We use kasan_check_byte(), which is supported for the hardware
* tag-based KASAN mode, unlike kasan_check_read/write().
@@ -1448,13 +1448,7 @@ size_t ksize(const void *objp)
if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
return 0;
- size = kfence_ksize(objp) ?: __ksize(objp);
- /*
- * We assume that ksize callers could use whole allocated area,
- * so we need to unpoison this area.
- */
- kasan_unpoison_range(objp, size);
- return size;
+ return kfence_ksize(objp) ?: __ksize(objp);
}
EXPORT_SYMBOL(ksize);