KASAN: vmalloc-out-of-bounds Write in pcpu_freelist

KASAN: vmalloc-out-of-bounds Write in pcpu_freelist_populate
Status: fixed on 2021/03/10 01:48
Reported-by: syzbot+942085bfb8f7a276af1c@syzkaller.appspotmail.com
Fix commit: e1868b9e36d0 bpf: Avoid overflows involving hash elem_size
First crash: 532d, last: 524d

Sample crash report:

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in pcpu_freelist_push_node kernel/bpf/percpu_freelist.c:33 [inline]
BUG: KASAN: vmalloc-out-of-bounds in pcpu_freelist_populate+0x1fe/0x260 kernel/bpf/percpu_freelist.c:114
Write of size 8 at addr ffffc9005bf5d798 by task syz-executor.2/317

CPU: 0 PID: 317 Comm: syz-executor.2 Not tainted 5.10.0-rc6-syzkaller #0
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+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x4c8 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 pcpu_freelist_push_node kernel/bpf/percpu_freelist.c:33 [inline]
 pcpu_freelist_populate+0x1fe/0x260 kernel/bpf/percpu_freelist.c:114
 prealloc_init kernel/bpf/hashtab.c:323 [inline]
 htab_map_alloc+0x981/0x1230 kernel/bpf/hashtab.c:507
 find_and_alloc_map kernel/bpf/syscall.c:123 [inline]
 map_create kernel/bpf/syscall.c:829 [inline]
 __do_sys_bpf+0xa81/0x5170 kernel/bpf/syscall.c:4374
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e159
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4775942c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e159
RDX: 0000000000000040 RSI: 00000000200001c0 RDI: 0000000000000000
RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffc8d513a5f R14: 00007f47759439c0 R15: 000000000119bf8c


Memory state around the buggy address:
 ffffc9005bf5d680: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc9005bf5d700: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
>ffffc9005bf5d780: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                            ^
 ffffc9005bf5d800: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc9005bf5d880: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Crashes (6):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	VM info
ci-upstream-net-kasan-gce	2020/12/11 10:43	net-next	91163f821436	f900b48c	.config	log	report	info
ci-upstream-bpf-next-kasan-gce	2020/12/07 05:43	bpf-next	34da87213d3d	c521566d	.config	log	report	info
ci-upstream-net-kasan-gce	2020/12/07 05:43	net-next	4054eebf0fb0	c521566d	.config	log	report	info
ci-upstream-bpf-next-kasan-gce	2020/12/05 02:25	bpf-next	eceae70bdeae	20366b87	.config	log	report	info
ci-upstream-bpf-next-kasan-gce	2020/12/04 21:39	bpf-next	eceae70bdeae	20366b87	.config	log	report	info
ci-upstream-bpf-next-kasan-gce	2020/12/03 19:43	bpf-next	97306be45fbe	e6b0d314	.config	log	report	info