Eric Dumazet 875c9839f7 bpf: Make sure mac_header was set before using it ... commit 0326195f52 upstream. Classic BPF has a way to load bytes starting from the mac header. Some skbs do not have a mac header, and skb_mac_header() in this case is returning a pointer that 65535 bytes after skb->head. Existing range check in bpf_internal_load_pointer_neg_helper() was properly kicking and no illegal access was happening. New sanity check in skb_mac_header() is firing, so we need to avoid it. WARNING: CPU: 1 PID: 28990 at include/linux/skbuff.h:2785 skb_mac_header include/linux/skbuff.h:2785 [inline] WARNING: CPU: 1 PID: 28990 at include/linux/skbuff.h:2785 bpf_internal_load_pointer_neg_helper+0x1b1/0x1c0 kernel/bpf/core.c:74 Modules linked in: CPU: 1 PID: 28990 Comm: syz-executor.0 Not tainted 5.19.0-rc4-syzkaller-00865-g4874fb9484be #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 RIP: 0010:skb_mac_header include/linux/skbuff.h:2785 [inline] RIP: 0010:bpf_internal_load_pointer_neg_helper+0x1b1/0x1c0 kernel/bpf/core.c:74 Code: ff ff 45 31 f6 e9 5a ff ff ff e8 aa 27 40 00 e9 3b ff ff ff e8 90 27 40 00 e9 df fe ff ff e8 86 27 40 00 eb 9e e8 2f 2c f3 ff <0f> 0b eb b1 e8 96 27 40 00 e9 79 fe ff ff 90 41 57 41 56 41 55 41 RSP: 0018:ffffc9000309f668 EFLAGS: 00010216 RAX: 0000000000000118 RBX: ffffffffffeff00c RCX: ffffc9000e417000 RDX: 0000000000040000 RSI: ffffffff81873f21 RDI: 0000000000000003 RBP: ffff8880842878c0 R08: 0000000000000003 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000001 R12: 0000000000000004 R13: ffff88803ac56c00 R14: 000000000000ffff R15: dffffc0000000000 FS: 00007f5c88a16700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdaa9f6c058 CR3: 000000003a82c000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ____bpf_skb_load_helper_32 net/core/filter.c:276 [inline] bpf_skb_load_helper_32+0x191/0x220 net/core/filter.c:264 Fixes: f9aefd6b2a ("net: warn if mac header was not set") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220707123900.945305-1-edumazet@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-07-29 17:06:51 +02:00
..
arraymap.c	bpf: sockmap, map_release does not hold refcnt for pinned maps	2018-11-04 14:52:44 +01:00
bpf_lru_list.c	bpf_lru_list: Read double-checked variable once without lock	2021-03-03 18:22:39 +01:00
bpf_lru_list.h	bpf: Only set node->ref = 1 if it has not been set	2017-09-01 09:57:39 -07:00
cgroup.c	bpf: BPF support for sock_ops	2017-07-01 16:15:13 -07:00
core.c	bpf: Make sure mac_header was set before using it	2022-07-29 17:06:51 +02:00
devmap.c	bpf: devmap: fix wrong interface selection in notifier_call	2019-12-01 09:13:47 +01:00
hashtab.c	bpf: Remove recursion prevention from rcu free callback	2020-10-01 13:12:35 +02:00
helpers.c	bpf: rename ARG_PTR_TO_STACK	2017-01-09 16:56:27 -05:00
inode.c	bpf: fix use after free in bpf_evict_inode	2019-04-20 09:15:07 +02:00
lpm_trie.c	bpf: fix rcu lockdep warning for lpm_trie map_free callback	2018-03-11 16:23:21 +01:00
Makefile	bpf: silence warning messages in core	2019-07-31 07:28:25 +02:00
map_in_map.c	bpf: fix inner map masking to prevent oob under speculation	2019-04-20 09:15:09 +02:00
map_in_map.h	bpf: Add syscall lookup support for fd array and htab	2017-06-29 13:13:25 -04:00
percpu_freelist.c	bpf: fix lockdep false positive in percpu_freelist	2019-03-13 14:03:20 -07:00
percpu_freelist.h	bpf: fix lockdep false positive in percpu_freelist	2019-03-13 14:03:20 -07:00
sockmap.c	bpf: sockmap, map_release does not hold refcnt for pinned maps	2018-11-04 14:52:44 +01:00
stackmap.c	bpf: Fix integer overflow in prealloc_elems_and_freelist()	2021-10-17 10:08:32 +02:00
syscall.c	bpf: Add kconfig knob for disabling unpriv bpf by default	2022-02-16 12:44:50 +01:00
tnum.c	bpf/verifier: track signed and unsigned min/max values	2017-08-08 17:51:34 -07:00
verifier.c	bpf: Fix the off-by-two error in range markings	2021-12-14 10:16:53 +01:00