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authorAndrey Konovalov <andreyknvl@google.com>2022-03-24 18:11:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-24 19:06:48 -0700
commit23689e91fb22c15b84ac6c22ad9942039792f3af (patch)
tree43d39324d73f7b154524c966a9d49ec552faf6d4 /kernel
parent9353ffa6e9e90d2b6348209cf2b95a8ffee18711 (diff)
kasan, vmalloc: add vmalloc tagging for HW_TAGS
Add vmalloc tagging support to HW_TAGS KASAN. The key difference between HW_TAGS and the other two KASAN modes when it comes to vmalloc: HW_TAGS KASAN can only assign tags to physical memory. The other two modes have shadow memory covering every mapped virtual memory region. Make __kasan_unpoison_vmalloc() for HW_TAGS KASAN: - Skip non-VM_ALLOC mappings as HW_TAGS KASAN can only tag a single mapping of normal physical memory; see the comment in the function. - Generate a random tag, tag the returned pointer and the allocation, and initialize the allocation at the same time. - Propagate the tag into the page stucts to allow accesses through page_address(vmalloc_to_page()). The rest of vmalloc-related KASAN hooks are not needed: - The shadow-related ones are fully skipped. - __kasan_poison_vmalloc() is kept as a no-op with a comment. Poisoning and zeroing of physical pages that are backing vmalloc() allocations are skipped via __GFP_SKIP_KASAN_UNPOISON and __GFP_SKIP_ZERO: __kasan_unpoison_vmalloc() does that instead. Enabling CONFIG_KASAN_VMALLOC with HW_TAGS is not yet allowed. Link: https://lkml.kernel.org/r/d19b2e9e59a9abc59d05b72dea8429dcaea739c6.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Co-developed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Collingbourne <pcc@google.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/scs.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/scs.c b/kernel/scs.c
index 579841be8864..b83bc9251f99 100644
--- a/kernel/scs.c
+++ b/kernel/scs.c
@@ -32,7 +32,7 @@ static void *__scs_alloc(int node)
for (i = 0; i < NR_CACHED_SCS; i++) {
s = this_cpu_xchg(scs_cache[i], NULL);
if (s) {
- kasan_unpoison_vmalloc(s, SCS_SIZE);
+ kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_NONE);
memset(s, 0, SCS_SIZE);
return s;
}
@@ -78,7 +78,7 @@ void scs_free(void *s)
if (this_cpu_cmpxchg(scs_cache[i], 0, s) == NULL)
return;
- kasan_unpoison_vmalloc(s, SCS_SIZE);
+ kasan_unpoison_vmalloc(s, SCS_SIZE, KASAN_VMALLOC_NONE);
vfree_atomic(s);
}