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Eric Dumazet 0c722a32f2 bpf: Make sure mac_header was set before using it 
commit 0326195f523a549e0a9d7fd44c70b26fd7265090 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: f9aefd6b2aa3 ("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 17:19:23 +02:00
..
preload
bpf: Fix umd memory leak in copy_process()
2021-03-30 14:32:03 +02:00
arraymap.c
bpf: Fix potential race in tail call compatibility check
2021-11-02 19:48:21 +01:00
bpf_inode_storage.c
bpf: Change inode_storage's lookup_elem return value from NULL to -EBADF
2021-03-30 14:31:56 +02:00
bpf_iter.c
bpf: Fix an unitialized value in bpf_iter
2021-03-04 11:37:33 +01:00
bpf_local_storage.c
bpf: Use hlist_add_head_rcu when linking to local_storage
2020-09-19 01:12:35 +02:00
bpf_lru_list.c
bpf_lru_list: Read double-checked variable once without lock
2021-03-04 11:37:29 +01:00
bpf_lru_list.h
bpf: Fix a typo "inacitve" -> "inactive"
2020-04-06 21:54:10 +02:00
bpf_lsm.c
bpf: Update verification logic for LSM programs
2020-11-06 13:15:21 -08:00
bpf_struct_ops_types.h
bpf: tcp: Support tcp_congestion_ops in bpf
2020-01-09 08:46:18 -08:00
bpf_struct_ops.c
bpf: Handle return value of BPF_PROG_TYPE_STRUCT_OPS prog
2021-10-06 15:55:50 +02:00
btf.c
bpf: Disallow BPF_LOG_KERNEL log level for bpf(BPF_BTF_LOAD)
2022-01-27 10:53:54 +01:00
cgroup.c
bpf, cgroup: Fix problematic bounds check
2021-02-10 09:29:12 +01:00
core.c
bpf: Make sure mac_header was set before using it
2022-07-29 17:19:23 +02:00
cpumap.c
bpf, cpumap: Remove rcpu pointer from cpu_map_build_skb signature
2020-09-28 23:30:42 +02:00
devmap.c
bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc
2021-12-17 10:14:41 +01:00
disasm.c
bpf: Introduce BPF nospec instruction for mitigating Spectre v4
2021-08-04 12:46:44 +02:00
disasm.h
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295
2019-06-05 17:36:38 +02:00
dispatcher.c
bpf: Remove bpf_image tree
2020-03-13 12:49:52 -07:00
hashtab.c
bpf: Fix integer overflow involving bucket_size
2021-08-18 08:59:10 +02:00
helpers.c
bpf: Fix potentially incorrect results with bpf_get_local_storage()
2021-09-03 10:09:31 +02:00
inode.c
bpf: link: Refuse non-O_RDWR flags in BPF_OBJ_GET
2021-04-14 08:42:00 +02:00
local_storage.c
bpf: Fix NULL pointer dereference in bpf_get_local_storage() helper
2021-09-03 10:09:21 +02:00
lpm_trie.c
bpf: Add map_meta_equal map ops
2020-08-28 15:41:30 +02:00
Makefile
bpf: Don't rely on GCC __attribute__((optimize)) to disable GCSE
2020-10-29 20:01:46 -07:00
map_in_map.c
bpf: Relax max_entries check for most of the inner map types
2020-08-28 15:41:30 +02:00
map_in_map.h
bpf: Add map_meta_equal map ops
2020-08-28 15:41:30 +02:00
map_iter.c
bpf: Implement link_query callbacks in map element iterators
2020-08-21 14:01:39 -07:00
net_namespace.c
bpf: Add support for forced LINK_DETACH command
2020-08-01 20:38:28 -07:00
offload.c
bpf, offload: Replace bitwise AND by logical AND in bpf_prog_offload_info_fill
2020-02-17 16:53:49 +01:00
percpu_freelist.c
bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI
2020-10-06 00:04:11 +02:00
percpu_freelist.h
bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI
2020-10-06 00:04:11 +02:00
prog_iter.c
bpf: Refactor bpf_iter_reg to have separate seq_info member
2020-07-25 20:16:32 -07:00
queue_stack_maps.c
bpf: Add map_meta_equal map ops
2020-08-28 15:41:30 +02:00
reuseport_array.c
bpf, net: Rework cookie generator as per-cpu one
2020-09-30 11:50:35 -07:00
ringbuf.c
bpf: Use VM_MAP instead of VM_ALLOC for ringbuf
2022-02-08 18:30:39 +01:00
stackmap.c
bpf: Fix incorrect memory charge cost calculation in stack_map_alloc()
2022-06-22 14:13:12 +02:00
syscall.c
bpf: Add schedule points in batch ops
2022-03-02 11:42:49 +01:00
sysfs_btf.c
bpf: Fix sysfs export of empty BTF section
2020-09-21 21:50:24 +02:00
task_iter.c
bpf: Save correct stopping point in file seq iteration
2021-01-19 18:27:28 +01:00
tnum.c
bpf: Verifier, do explicit ALU32 bounds tracking
2020-03-30 14:59:53 -07:00
trampoline.c
bpf: Fix potential array overflow in bpf_trampoline_get_progs()
2022-06-06 08:42:45 +02:00
verifier.c
bpf: Fix insufficient bounds propagation from adjust_scalar_min_max_vals
2022-07-12 16:32:17 +02:00