On Wed, Oct 17, 2018 at 08:37:39PM -0700, John Fastabend wrote:
> Before using the psock returned by sk_psock_get() when adding it to a
> sockmap we need to ensure it is actually a sockmap based psock.
> Previously we were only checking this after incrementing the reference
> counter which was an error. This resulted in a slab-out-of-bounds
> error when the psock was not actually a sockmap type.
>
> This moves the check up so the reference counter is only used
> if it is a sockmap psock.
>
> Eric reported the following KASAN BUG,
>
> BUG: KASAN: slab-out-of-bounds in atomic_read
> include/asm-generic/atomic-instrumented.h:21 [inline]
> BUG: KASAN: slab-out-of-bounds in refcount_inc_not_zero_checked+0x97/0x2f0
> lib/refcount.c:120
> Read of size 4 at addr ffff88019548be58 by task syz-executor4/22387
>
> CPU: 1 PID: 22387 Comm: syz-executor4 Not tainted 4.19.0-rc7+ #264
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
> print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
> kasan_report_error mm/kasan/report.c:354 [inline]
> kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
> check_memory_region_inline mm/kasan/kasan.c:260 [inline]
> check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
> kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
> atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
> refcount_inc_not_zero_checked+0x97/0x2f0 lib/refcount.c:120
> sk_psock_get include/linux/skmsg.h:379 [inline]
> sock_map_link.isra.6+0x41f/0xe30 net/core/sock_map.c:178
> sock_hash_update_common+0x19b/0x11e0 net/core/sock_map.c:669
> sock_hash_update_elem+0x306/0x470 net/core/sock_map.c:738
> map_update_elem+0x819/0xdf0 kernel/bpf/syscall.c:818
>
> Signed-off-by: John Fastabend <john.fastab...@gmail.com>
> Reported-by: Eric Dumazet <eric.duma...@gmail.com>
> Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
> ---
> 0 files changed
something isn't right here.
It messed up the cover letter as well.
Please fix your scripts and resubmit.
