From: Kees Cook <keescook@chromium.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
"GONG, Ruiqi" <gongruiqi@huaweicloud.com>,
Xiu Jianfeng <xiujianfeng@huawei.com>,
Suren Baghdasaryan <surenb@google.com>,
Kent Overstreet <kent.overstreet@linux.dev>,
Jann Horn <jannh@google.com>,
Matteo Rizzo <matteorizzo@google.com>,
linux-mm@kvack.org, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH v2 9/9] mm/util: Use dedicated slab buckets for memdup_user()
Date: Tue, 5 Mar 2024 02:10:25 -0800 [thread overview]
Message-ID: <20240305101026.694758-9-keescook@chromium.org> (raw)
In-Reply-To: <20240305100933.it.923-kees@kernel.org>
Both memdup_user() and vmemdup_user() handle allocations that are
regularly used for exploiting use-after-free type confusion flaws in
the kernel (e.g. prctl() PR_SET_VMA_ANON_NAME[1] and setxattr[2][3][4]
respectively).
Since both are designed for contents coming from userspace, it allows
for userspace-controlled allocation sizes. Use a dedicated set of kmalloc
buckets so these allocations do not share caches with the global kmalloc
buckets.
After a fresh boot under Ubuntu 23.10, we can see the caches are already
in active use:
# grep ^memdup /proc/slabinfo
memdup_user-8k 4 4 8192 4 8 : ...
memdup_user-4k 8 8 4096 8 8 : ...
memdup_user-2k 16 16 2048 16 8 : ...
memdup_user-1k 0 0 1024 16 4 : ...
memdup_user-512 0 0 512 16 2 : ...
memdup_user-256 0 0 256 16 1 : ...
memdup_user-128 0 0 128 32 1 : ...
memdup_user-64 256 256 64 64 1 : ...
memdup_user-32 512 512 32 128 1 : ...
memdup_user-16 1024 1024 16 256 1 : ...
memdup_user-8 2048 2048 8 512 1 : ...
memdup_user-192 0 0 192 21 1 : ...
memdup_user-96 168 168 96 42 1 : ...
Link: https://starlabs.sg/blog/2023/07-prctl-anon_vma_name-an-amusing-heap-spray/ [1]
Link: https://duasynt.com/blog/linux-kernel-heap-spray [2]
Link: https://etenal.me/archives/1336 [3]
Link: https://github.com/a13xp0p0v/kernel-hack-drill/blob/master/drill_exploit_uaf.c [4]
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "GONG, Ruiqi" <gongruiqi@huaweicloud.com>
Cc: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Jann Horn <jannh@google.com>
Cc: Matteo Rizzo <matteorizzo@google.com>
Cc: linux-mm@kvack.org
---
mm/util.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/mm/util.c b/mm/util.c
index 02c895b87a28..25b9122022a7 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -181,6 +181,16 @@ char *kmemdup_nul(const char *s, size_t len, gfp_t gfp)
}
EXPORT_SYMBOL(kmemdup_nul);
+static kmem_buckets *user_buckets __ro_after_init;
+
+static int __init init_user_buckets(void)
+{
+ user_buckets = kmem_buckets_create("memdup_user", 0, 0, 0, INT_MAX, NULL);
+
+ return 0;
+}
+subsys_initcall(init_user_buckets);
+
/**
* memdup_user - duplicate memory region from user space
*
@@ -194,7 +204,7 @@ void *memdup_user(const void __user *src, size_t len)
{
void *p;
- p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN);
+ p = kmem_buckets_alloc_track_caller(user_buckets, len, GFP_USER | __GFP_NOWARN);
if (!p)
return ERR_PTR(-ENOMEM);
@@ -220,7 +230,7 @@ void *vmemdup_user(const void __user *src, size_t len)
{
void *p;
- p = kvmalloc(len, GFP_USER);
+ p = kmem_buckets_valloc(user_buckets, len, GFP_USER);
if (!p)
return ERR_PTR(-ENOMEM);
--
2.34.1
next prev parent reply other threads:[~2024-03-05 10:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-05 10:10 [PATCH v2 0/9] slab: Introduce dedicated bucket allocator Kees Cook
2024-03-05 10:10 ` [PATCH v2 1/9] slab: Introduce kmem_buckets typedef Kees Cook
2024-03-05 10:10 ` [PATCH v2 2/9] slub: Plumb kmem_buckets into __do_kmalloc_node() Kees Cook
2024-03-05 10:10 ` [PATCH v2 3/9] util: Introduce __kvmalloc_node() that can take kmem_buckets argument Kees Cook
2024-03-05 10:10 ` [PATCH v2 4/9] slab: Introduce kmem_buckets_create() Kees Cook
2024-03-25 19:40 ` Kent Overstreet
2024-03-25 20:40 ` Kees Cook
2024-03-25 21:49 ` Kent Overstreet
2024-03-25 23:13 ` Kees Cook
2024-03-05 10:10 ` [PATCH v2 5/9] slab: Introduce kmem_buckets_alloc() Kees Cook
2024-03-05 10:10 ` [PATCH v2 6/9] slub: Introduce kmem_buckets_alloc_track_caller() Kees Cook
2024-03-05 10:10 ` [PATCH v2 7/9] slab: Introduce kmem_buckets_valloc() Kees Cook
2024-03-05 10:10 ` [PATCH v2 8/9] ipc, msg: Use dedicated slab buckets for alloc_msg() Kees Cook
2024-03-05 10:10 ` Kees Cook [this message]
2024-03-06 1:47 ` [PATCH v2 0/9] slab: Introduce dedicated bucket allocator GONG, Ruiqi
2024-03-07 20:31 ` Kees Cook
2024-03-15 10:28 ` GONG, Ruiqi
2024-03-25 9:03 ` Vlastimil Babka
2024-03-25 18:24 ` Kees Cook
2024-03-26 18:07 ` julien.voisin
2024-03-26 19:41 ` Kees Cook
2024-03-25 19:32 ` Kent Overstreet
2024-03-25 20:26 ` Kees Cook
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