Messages in this thread | | | From | Jens Wiklander <> | Date | Thu, 12 Sep 2019 12:04:18 +0200 | Subject | Re: [PATCH] tee: fix kasan check slab-out-of-bounds error. |
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Hi Chunguo,
On Thu, Sep 12, 2019 at 10:36 AM chunguo feng <chunguo.feng@amlogic.com> wrote: > > From: fengchunguo <chunguo.feng@amlogic.com> > > Physical address should be set one shifting, but not cover shm struct data. > If offs was set 0, it cause KASAN error. > > Log: > [22.345259@0] BUG: KASAN: slab-out-of-bounds in optee_handle_rpc+0x644/0x858 > [22.352221@0] Read of size 4 at addr ffffffc0445485dc by task tee_preload_fw/2505 > [22.361280@0] CPU: 0 PID: 2505 Comm: tee_preload_fw Tainted: G B W O > 4.19.53-01721-g11b1db7-dirty #417 > [22.376617@0] Call trace: > [22.379220@0] dump_backtrace+0x0/0x1b4 > [22.383003@0] show_stack+0x20/0x28 > [22.386459@0] dump_stack+0x8c/0xb4 > [22.389909@0] print_address_description+0x10c/0x274 > [22.394819@0] kasan_report+0x224/0x370 > [22.398616@0] __asan_load4+0x6c/0x84 > [22.402238@0] optee_handle_rpc+0x644/0x858 > [22.406375@0] optee_do_call_with_arg+0x148/0x160 > [22.411033@0] optee_open_session+0x1b0/0x340 > [22.415352@0] tee_ioctl_open_session+0x28c/0x784 > [22.420006@0] tee_ioctl+0x210/0x800 > [22.423546@0] do_vfs_ioctl+0x104/0xe7c > [22.427337@0] __arm64_sys_ioctl+0xac/0xc0 > [22.431393@0] invoke_syscall+0xd4/0xf4 > [22.435187@0] el0_svc_common+0x88/0x128 > [22.439066@0] el0_svc_handler+0x40/0x84 > [22.442947@0] el0_svc+0x8/0xc > [22.445962@0] > [22.447602@0] Allocated by task 2508: > [22.451231@0] kasan_kmalloc.part.5+0x50/0x124 > [22.455627@0] kasan_kmalloc+0xc4/0xe4 > [22.459334@0] kmem_cache_alloc_trace+0x154/0x2bc > [22.463994@0] tee_shm_alloc+0xa0/0x340 > [22.467788@0] tee_ioctl+0x39c/0x800 > [22.471324@0] do_vfs_ioctl+0x104/0xe7c > [22.475119@0] __arm64_sys_ioctl+0xac/0xc0 > [22.479172@0] invoke_syscall+0xd4/0xf4 > [22.482967@0] el0_svc_common+0x88/0x128 > [22.486849@0] el0_svc_handler+0x40/0x84 > [22.490728@0] el0_svc+0x8/0xc > [22.493743@0] > [22.495384@0] Freed by task 0: > [22.498408@0] __kasan_slab_free+0x11c/0x21c > [22.502631@0] kasan_slab_free+0x10/0x18 > [22.506511@0] kfree+0x8c/0x284 > [22.509625@0] selinux_cred_free+0x48/0x64 > [22.513672@0] security_cred_free+0x48/0x64 > [22.517817@0] put_cred_rcu+0x3c/0x108 > [22.521523@0] rcu_process_callbacks+0x308/0x7ac > [22.526092@0] __do_softirq+0x1c8/0x5c8 > [22.529882@0] > [22.531527@0] The buggy address belongs to the object at ffffffc044548580 > [22.531527@0] which belongs to the cache kmalloc-128 of size 128 > [22.544291@0] The buggy address is located 92 bytes inside of > [22.544291@0] 128-byte region [ffffffc044548580, ffffffc044548600) > [22.556190@0] The buggy address belongs to the page: > [22.561110@0] page:ffffffbf01115200 count:1 mapcount:0 mapping:ffffffc04540c400 index:0x0 compound_mapcount: 0 > [22.571029@0] flags: 0x20094e4b00010200(slab|head) > [22.575780@0] raw: 20094e4b00010200 ffffffbf01113408 ffffffbf01119508 ffffffc04540c400 > [22.583622@0] raw: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000 > [22.591466@0] page dumped because: kasan: bad access detected > [22.597157@0] > [22.598797@0] Memory state around the buggy address: > [22.603719@0] ffffffc044548480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [22.611048@0] ffffffc044548500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [22.618379@0] >ffffffc044548580: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc > [22.625707@0] ^ > [22.631920@0] ffffffc044548600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [22.639251@0] ffffffc044548680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [22.646580@0] ================================================================== > > Test: > 1. Set offs range,then test tee_preload successfully. > / # tee_preload_fw > use default tee_preload_fw pathfw_path=/lib/firmware/video/video_ucode.bin > tee preload video fw ok > / # echo $? > 0 > > Signed-off-by: fengchunguo <chunguo.feng@amlogic.com> > --- > drivers/tee/tee_shm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index 0b9ab1d0dd45..585361cd8dd9 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -461,7 +461,7 @@ int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa) > if (offs >= shm->size) > return -EINVAL; > if (pa) > - *pa = shm->paddr + offs; > + *pa = shm->paddr + shm->size;
This can't be right, "offs" is used to calculate the physical address from the start of a shared memory range. With this you're ignoring "offs" and always return past the end of the region. I don't see how that can help.
Cheers, Jens
> return 0; > } > EXPORT_SYMBOL_GPL(tee_shm_get_pa); > -- > 2.22.0 >
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