stable team,
please consider
commit 49f2d2419d60a103752e5fbaf158cf8d07c0d884
usercopy: mark dma-kmalloc caches as usercopy caches
for stable.
-------- Forwarded Message --------
Subject: [merged] usercopy-mark-dma-kmalloc-caches-as-usercopy-caches.patch
removed from -mm tree
Date: Tue, 02 Jun 2020 14:37:44 -0700
From: [email protected]
To: [email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected], [email protected],
[email protected], [email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
[email protected], [email protected], [email protected],
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The patch titled
Subject: usercopy: mark dma-kmalloc caches as usercopy caches
has been removed from the -mm tree. Its filename was
usercopy-mark-dma-kmalloc-caches-as-usercopy-caches.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Vlastimil Babka <[email protected]>
Subject: usercopy: mark dma-kmalloc caches as usercopy caches
We have seen a "usercopy: Kernel memory overwrite attempt detected to SLUB
object 'dma-kmalloc-1 k' (offset 0, size 11)!" error on s390x, as IUCV
uses kmalloc() with __GFP_DMA because of memory address restrictions. The
issue has been discussed [2] and it has been noted that if all the kmalloc
caches are marked as usercopy, there's little reason not to mark
dma-kmalloc caches too. The 'dma' part merely means that __GFP_DMA is
used to restrict memory address range.
As Jann Horn put it [3]:
"I think dma-kmalloc slabs should be handled the same way as normal
kmalloc slabs. When a dma-kmalloc allocation is freshly created, it is
just normal kernel memory - even if it might later be used for DMA -, and
it should be perfectly fine to copy_from_user() into such allocations at
that point, and to copy_to_user() out of them at the end. If you look at
the places where such allocations are created, you can see things like
kmemdup(), memcpy() and so on - all normal operations that shouldn't
conceptually be different from usercopy in any relevant way."
Thus this patch marks the dma-kmalloc-* caches as usercopy.
[1] https://bugzilla.suse.com/show_bug.cgi?id=1156053
[2]
https://lore.kernel.org/kernel-hardening/[email protected]/
[3]
https://lore.kernel.org/kernel-hardening/CAG48ez1a4waGk9kB0WLaSbs4muSoK0AYAVk8=xyakj4_+6e...@mail.gmail.com/
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Acked-by: Jiri Slaby <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Christopher Lameter <[email protected]>
Cc: Julian Wiedmann <[email protected]>
Cc: Ursula Braun <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: David Windsor <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Christoffer Dall <[email protected]>
Cc: Dave Kleikamp <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Luis de Bethencourt <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Matthew Garrett <[email protected]>
Cc: Michal Kubecek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
mm/slab_common.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/slab_common.c~usercopy-mark-dma-kmalloc-caches-as-usercopy-caches
+++ a/mm/slab_common.c
@@ -1303,7 +1303,8 @@ void __init create_kmalloc_caches(slab_f
kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
kmalloc_info[i].name[KMALLOC_DMA],
kmalloc_info[i].size,
- SLAB_CACHE_DMA | flags, 0, 0);
+ SLAB_CACHE_DMA | flags, 0,
+ kmalloc_info[i].size);
}
}
#endif
_
Patches currently in -mm which might be from [email protected] are
kernel-sysctl-support-setting-sysctl-parameters-from-kernel-command-line.patch
kernel-sysctl-support-handling-command-line-aliases.patch
kernel-hung_task-convert-hung_task_panic-boot-parameter-to-sysctl.patch
tools-testing-selftests-sysctl-sysctlsh-support-config_test_sysctl=y.patch
lib-test_sysctl-support-testing-of-sysctl-boot-parameter.patch
lib-test_sysctl-support-testing-of-sysctl-boot-parameter-fix.patch
