From: glider@google.com
To: walter-zh.wu@mediatek.com, dvyukov@google.com,
gregkh@linuxfoundation.org, akpm@linux-foundation.org
Cc: matthias.bgg@gmail.com, tglx@linutronix.de, jpoimboe@redhat.com,
kstewart@linuxfoundation.org, linux-mm@kvack.org,
Alexander Potapenko <glider@google.com>
Subject: [PATCH] lib/stackdepot: fix global out-of-bounds in stack_slabs
Date: Mon, 3 Feb 2020 11:29:53 +0100 [thread overview]
Message-ID: <20200203102953.17349-1-glider@google.com> (raw)
Walter Wu has reported a potential case in which init_stack_slab() is
called after stack_slabs[STACK_ALLOC_MAX_SLABS - 1] has already been
initialized. In that case init_stack_slab() will overwrite
stack_slabs[STACK_ALLOC_MAX_SLABS], which may result in a memory
corruption.
Fixes: cd11016e5f521 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB")
Reported-by: Walter Wu <walter-zh.wu@mediatek.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alexander Potapenko <glider@google.com>
---
lib/stackdepot.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index ed717dd08ff3..3580e92cac99 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -84,7 +84,9 @@ static bool init_stack_slab(void **prealloc)
if (stack_slabs[depot_index] == NULL) {
stack_slabs[depot_index] = *prealloc;
} else {
- stack_slabs[depot_index + 1] = *prealloc;
+ /* If this is the last depot slab, do not touch the next one. */
+ if (depot_index + 1 < STACK_ALLOC_MAX_SLABS)
+ stack_slabs[depot_index + 1] = *prealloc;
/*
* This smp_store_release pairs with smp_load_acquire() from
* |next_slab_inited| above and in stack_depot_save().
--
2.25.0.341.g760bfbb309-goog
next reply other threads:[~2020-02-03 10:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-03 10:29 glider [this message]
2020-02-03 11:02 ` [PATCH] lib/stackdepot: fix global out-of-bounds in stack_slabs Tetsuo Handa
2020-02-03 11:10 ` Alexander Potapenko
2020-02-18 10:29 glider
2020-02-19 21:37 ` Andrew Morton
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