On Thu, Sep 12, 2019 at 12:48 PM [email protected] <[email protected]> wrote: > > Hi Jens, > > Thanks for your comment. > > Refer to the current solution, PC point was from > optee_handle_rpc->tee_shm_get_pa. > > If offs was set 0, pa was located other memory again, could you please > kindly offer the better way?
The entire range one piece of shared memory should be usable, so if kasan is upset then I guess that the shm has been corrupted in some way. I'm a bit puzzled because I can't see any access using the calculated physical address around this. Perhaps the problem occurred earlier and was just noticed now? > > In my options, offs should be set other location, other was offs of value set > other limitiation? I'm sorry I don't understand. Offs is normally 0 to be able to access the shared memory from the start of the range. Cheers, Jens > > Thanks, > > BRs, > Gary. > > > From: Jens Wiklander > Date: 2019-09-12 18:04 > To: chunguo feng > CC: Linux Kernel Mailing List > Subject: Re: [PATCH] tee: fix kasan check slab-out-of-bounds error. > Hi Chunguo, > > On Thu, Sep 12, 2019 at 10:36 AM chunguo feng <[email protected]> > wrote: > > > > From: fengchunguo <[email protected]> > > > > 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 <[email protected]> > > --- > > 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 > > >
