kasan: refactor pcpu kasan vmalloc unpoison

commit 6f13db031e27e88213381039032a9cc061578ea6 upstream.

A KASAN tag mismatch, possibly causing a kernel panic, can be observed
on systems with a tag-based KASAN enabled and with multiple NUMA nodes.
It was reported on arm64 and reproduced on x86. It can be explained in
the following points:

1. There can be more than one virtual memory chunk.
2. Chunk's base address has a tag.
3. The base address points at the first chunk and thus inherits
   the tag of the first chunk.
4. The subsequent chunks will be accessed with the tag from the
   first chunk.
5. Thus, the subsequent chunks need to have their tag set to
   match that of the first chunk.

Refactor code by reusing __kasan_unpoison_vmalloc in a new helper in
preparation for the actual fix.

Link: https://lkml.kernel.org/r/eb61d93b907e262eefcaa130261a08bcb6c5ce51.1764874575.git.m.wieczorretman@pm.me
Fixes: 1d96320f8d53 ("kasan, vmalloc: add vmalloc tagging for SW_TAGS")
Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>
Cc: Kees Cook <kees@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>	[6.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 6d7972bb390cace8afbea52eab0fc3370313799b..cde493cb7702d28ab44b2d8c974d3be2cea1b305 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -615,6 +615,16 @@ static __always_inline void kasan_poison_vmalloc(const void *start,
                __kasan_poison_vmalloc(start, size);
 }
 
+void __kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                                kasan_vmalloc_flags_t flags);
+static __always_inline void
+kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                         kasan_vmalloc_flags_t flags)
+{
+       if (kasan_enabled())
+               __kasan_unpoison_vmap_areas(vms, nr_vms, flags);
+}
+
 #else /* CONFIG_KASAN_VMALLOC */
 
 static inline void kasan_populate_early_vm_area_shadow(void *start,
@@ -639,6 +649,11 @@ static inline void *kasan_unpoison_vmalloc(const void *start,
 static inline void kasan_poison_vmalloc(const void *start, unsigned long size)
 { }
 
+static __always_inline void
+kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                         kasan_vmalloc_flags_t flags)
+{ }
+
 #endif /* CONFIG_KASAN_VMALLOC */
 
 #if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index d4c14359feaf9d8fb4e92374ee9f9569c41d3574..1ed6289d471aa0a472df98f3efa65ba7d9f6a8b5 100644 (file)
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -28,6 +28,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/bug.h>
+#include <linux/vmalloc.h>
 
 #include "kasan.h"
 #include "../slab.h"
@@ -582,3 +583,19 @@ bool __kasan_check_byte(const void *address, unsigned long ip)
        }
        return true;
 }
+
+#ifdef CONFIG_KASAN_VMALLOC
+void __kasan_unpoison_vmap_areas(struct vm_struct **vms, int nr_vms,
+                                kasan_vmalloc_flags_t flags)
+{
+       unsigned long size;
+       void *addr;
+       int area;
+
+       for (area = 0 ; area < nr_vms ; area++) {
+               size = vms[area]->size;
+               addr = vms[area]->addr;
+               vms[area]->addr = __kasan_unpoison_vmalloc(addr, size, flags);
+       }
+}
+#endif

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 22a73a087135b22657ce9ce4f62fbebd5eb2173c..33e705ccafbaa4dc81a2b8926ca0b1d47c736a0e 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4872,9 +4872,7 @@ retry:
         * With hardware tag-based KASAN, marking is skipped for
         * non-VM_ALLOC mappings, see __kasan_unpoison_vmalloc().
         */
-       for (area = 0; area < nr_vms; area++)
-               vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr,
-                               vms[area]->size, KASAN_VMALLOC_PROT_NORMAL);
+       kasan_unpoison_vmap_areas(vms, nr_vms, KASAN_VMALLOC_PROT_NORMAL);
 
        kfree(vas);
        return vms;