On Fri, 19 May 2023, Sasha Levin wrote: > From: Lee Jones <lee@xxxxxxxxxx> > > [ 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@xxxxxxxxxx> > Signed-off-by: Jassi Brar <jaswinder.singh@xxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > 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]
