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| author | Yonghong Song <yhs@fb.com> | 2018-05-17 00:06:26 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-05-17 01:56:06 +0300 |
| commit | 683d2ac3904c74a625ea62d7fcc6c1efd84be087 (patch) | |
| tree | dbc972b583f5e8757add489f904213d358207c3e /kernel | |
| parent | f0307a7ed17fa8925321a4f58f5ca56eeedd4fa3 (diff) | |
| download | linux-683d2ac3904c74a625ea62d7fcc6c1efd84be087.tar.xz | |
bpf: fix sock hashmap kmalloc warning
syzbot reported a kernel warning below:
WARNING: CPU: 0 PID: 4499 at mm/slab_common.c:996 kmalloc_slab+0x56/0x70 mm/slab_common.c:996
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 4499 Comm: syz-executor050 Not tainted 4.17.0-rc3+ #9
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+0x1b9/0x294 lib/dump_stack.c:113
panic+0x22f/0x4de kernel/panic.c:184
__warn.cold.8+0x163/0x1b3 kernel/panic.c:536
report_bug+0x252/0x2d0 lib/bug.c:186
fixup_bug arch/x86/kernel/traps.c:178 [inline]
do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296
do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:kmalloc_slab+0x56/0x70 mm/slab_common.c:996
RSP: 0018:ffff8801d907fc58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8801aeecb280 RCX: ffffffff8185ebd7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000ffffffe1
RBP: ffff8801d907fc58 R08: ffff8801adb5e1c0 R09: ffffed0035a84700
R10: ffffed0035a84700 R11: ffff8801ad423803 R12: ffff8801aeecb280
R13: 00000000fffffff4 R14: ffff8801ad891a00 R15: 00000000014200c0
__do_kmalloc mm/slab.c:3713 [inline]
__kmalloc+0x25/0x760 mm/slab.c:3727
kmalloc include/linux/slab.h:517 [inline]
map_get_next_key+0x24a/0x640 kernel/bpf/syscall.c:858
__do_sys_bpf kernel/bpf/syscall.c:2131 [inline]
__se_sys_bpf kernel/bpf/syscall.c:2096 [inline]
__x64_sys_bpf+0x354/0x4f0 kernel/bpf/syscall.c:2096
do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The test case is against sock hashmap with a key size 0xffffffe1.
Such a large key size will cause the below code in function
sock_hash_alloc() overflowing and produces a smaller elem_size,
hence map creation will be successful.
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
Later, when map_get_next_key is called and kernel tries
to allocate the key unsuccessfully, it will issue
the above warning.
Similar to hashtab, ensure the key size is at most
MAX_BPF_STACK for a successful map creation.
Fixes: 81110384441a ("bpf: sockmap, add hash map support")
Reported-by: syzbot+e4566d29080e7f3460ff@syzkaller.appspotmail.com
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/sockmap.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 56879c9fd3a4..79f5e8988889 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -1990,6 +1990,12 @@ static struct bpf_map *sock_hash_alloc(union bpf_attr *attr) attr->map_flags & ~SOCK_CREATE_FLAG_MASK) return ERR_PTR(-EINVAL); + if (attr->key_size > MAX_BPF_STACK) + /* eBPF programs initialize keys on stack, so they cannot be + * larger than max stack size + */ + return ERR_PTR(-E2BIG); + err = bpf_tcp_ulp_register(); if (err && err != -EEXIST) return ERR_PTR(err); |