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Message-ID: <20230605155605.GA2357572@google.com>
Date: Mon, 5 Jun 2023 16:56:05 +0100
From: Lee Jones <lee@...nel.org>
To: Sasha Levin <sashal@...nel.org>
Cc: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
Jassi Brar <jaswinder.singh@...aro.org>,
jassisinghbrar@...il.com
Subject: Re: [PATCH AUTOSEL 6.3] mailbox: mailbox-test: Fix potential
double-free in mbox_test_message_write()
On Fri, 19 May 2023, Sasha Levin wrote:
> From: Lee Jones <lee@...nel.org>
>
> [ Upstream commit 2d1e952a2b8e5e92d8d55ac88a7cf7ca5ea591ad ]
>
> If a user can make copy_from_user() fail, there is a potential for
> UAF/DF due to a lack of locking around the allocation, use and freeing
> of the data buffers.
>
> This issue is not theoretical. I managed to author a POC for it:
>
> BUG: KASAN: double-free in kfree+0x5c/0xac
> Free of addr ffff29280be5de00 by task poc/356
> CPU: 1 PID: 356 Comm: poc Not tainted 6.1.0-00001-g961aa6552c04-dirty #20
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> dump_backtrace.part.0+0xe0/0xf0
> show_stack+0x18/0x40
> dump_stack_lvl+0x64/0x80
> print_report+0x188/0x48c
> kasan_report_invalid_free+0xa0/0xc0
> ____kasan_slab_free+0x174/0x1b0
> __kasan_slab_free+0x18/0x24
> __kmem_cache_free+0x130/0x2e0
> kfree+0x5c/0xac
> mbox_test_message_write+0x208/0x29c
> full_proxy_write+0x90/0xf0
> vfs_write+0x154/0x440
> ksys_write+0xcc/0x180
> __arm64_sys_write+0x44/0x60
> invoke_syscall+0x60/0x190
> el0_svc_common.constprop.0+0x7c/0x160
> do_el0_svc+0x40/0xf0
> el0_svc+0x2c/0x6c
> el0t_64_sync_handler+0xf4/0x120
> el0t_64_sync+0x18c/0x190
>
> Allocated by task 356:
> kasan_save_stack+0x3c/0x70
> kasan_set_track+0x2c/0x40
> kasan_save_alloc_info+0x24/0x34
> __kasan_kmalloc+0xb8/0xc0
> kmalloc_trace+0x58/0x70
> mbox_test_message_write+0x6c/0x29c
> full_proxy_write+0x90/0xf0
> vfs_write+0x154/0x440
> ksys_write+0xcc/0x180
> __arm64_sys_write+0x44/0x60
> invoke_syscall+0x60/0x190
> el0_svc_common.constprop.0+0x7c/0x160
> do_el0_svc+0x40/0xf0
> el0_svc+0x2c/0x6c
> el0t_64_sync_handler+0xf4/0x120
> el0t_64_sync+0x18c/0x190
>
> Freed by task 357:
> kasan_save_stack+0x3c/0x70
> kasan_set_track+0x2c/0x40
> kasan_save_free_info+0x38/0x5c
> ____kasan_slab_free+0x13c/0x1b0
> __kasan_slab_free+0x18/0x24
> __kmem_cache_free+0x130/0x2e0
> kfree+0x5c/0xac
> mbox_test_message_write+0x208/0x29c
> full_proxy_write+0x90/0xf0
> vfs_write+0x154/0x440
> ksys_write+0xcc/0x180
> __arm64_sys_write+0x44/0x60
> invoke_syscall+0x60/0x190
> el0_svc_common.constprop.0+0x7c/0x160
> do_el0_svc+0x40/0xf0
> el0_svc+0x2c/0x6c
> el0t_64_sync_handler+0xf4/0x120
> el0t_64_sync+0x18c/0x190
>
> Signed-off-by: Lee Jones <lee@...nel.org>
> Signed-off-by: Jassi Brar <jaswinder.singh@...aro.org>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
> drivers/mailbox/mailbox-test.c | 7 +++++++
> 1 file changed, 7 insertions(+)
Could you ensure the follow-up patch is also applied to all branches please?
8fe72b76db79d mailbox: mailbox-test: fix a locking issue in mbox_test_message_write()
--
Lee Jones [李琼斯]
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