Eric Dumazet ee3efa5ee1 bpf: Make sure mac_header was set before using it ... BugLink: https://bugs.launchpad.net/bugs/1988479 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> Signed-off-by: Kamal Mostafa <kamal@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>		2022-09-16 10:53:27 +02:00
..
preload
arraymap.c
bpf_inode_storage.c
bpf_iter.c
bpf_local_storage.c
bpf_lru_list.c
bpf_lru_list.h
bpf_lsm.c
bpf_struct_ops_types.h
bpf_struct_ops.c
bpf_task_storage.c
btf.c
cgroup.c
core.c	bpf: Make sure mac_header was set before using it	2022-09-16 10:53:27 +02:00
cpumap.c
devmap.c
disasm.c
disasm.h
dispatcher.c
hashtab.c
helpers.c
inode.c
Kconfig
local_storage.c
lpm_trie.c
Makefile
map_in_map.c
map_in_map.h
map_iter.c
net_namespace.c
offload.c
percpu_freelist.c
percpu_freelist.h
prog_iter.c
queue_stack_maps.c
reuseport_array.c
ringbuf.c
stackmap.c
syscall.c
sysfs_btf.c
task_iter.c
tnum.c
trampoline.c
verifier.c	bpf: Stop caching subprog index in the bpf_pseudo_func insn	2022-09-16 10:52:03 +02:00