On Mon, 13 Feb 2023 at 12:05, Kees Cook <kees@xxxxxxxxxx> wrote: > > On February 11, 2023 8:08:52 AM PST, syzbot <syzbot+cdd9922704fc75e03ffc@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > >Hello, > > > >syzbot found the following issue on: > > > >HEAD commit: ca72d58361ee Merge branch 'for-next/core' into for-kernelci > >git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci > >console output: https://syzkaller.appspot.com/x/log.txt?x=14a882f3480000 > >kernel config: https://syzkaller.appspot.com/x/.config?x=f3e78232c1ed2b43 > >dashboard link: https://syzkaller.appspot.com/bug?extid=cdd9922704fc75e03ffc > >compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > >userspace arch: arm64 > >syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1203777b480000 > >C reproducer: https://syzkaller.appspot.com/x/repro.c?x=124c1ea3480000 > > > >Downloadable assets: > >disk image: https://storage.googleapis.com/syzbot-assets/e2c91688b4cd/disk-ca72d583.raw.xz > >vmlinux: https://storage.googleapis.com/syzbot-assets/af105438bee6/vmlinux-ca72d583.xz > >kernel image: https://storage.googleapis.com/syzbot-assets/4a28ec4f8f7e/Image-ca72d583.gz.xz > > > >IMPORTANT: if you fix the issue, please add the following tag to the commit: > >Reported-by: syzbot+cdd9922704fc75e03ffc@xxxxxxxxxxxxxxxxxxxxxxxxx > > > >usercopy: Kernel memory overwrite attempt detected to SLUB object 'pid' (offset 24, size 24)! > > This looks like some serious memory corruption. The pid slab is 24 bytes in size, but struct io_open is larger... Possible UAF after the memory being reallocated to a new slab?? We've just noticed that some of syzbot arm64 configs did not enable KASAN, so it could produce false one-off reports caused by previous silent memory corruptions. So if you don't see anything obvious, don't spend too much time looking at it. #syz invalid > -Kees > > > [...] > >Call trace: > > usercopy_abort+0x90/0x94 > > __check_heap_object+0xa8/0x100 > > __check_object_size+0x208/0x6b8 > > io_openat2_prep+0xcc/0x2b8 > > io_submit_sqes+0x338/0xbb8 > > __arm64_sys_io_uring_enter+0x168/0x1308 > > invoke_syscall+0x64/0x178 > > el0_svc_common+0xbc/0x180 > > do_el0_svc+0x48/0x110 > > el0_svc+0x58/0x14c > > el0t_64_sync_handler+0x84/0xf0 > > el0t_64_sync+0x190/0x194 > > > > -- > Kees Cook
