3239534a79
when tcf_bpf_init_from_ops() fails (e.g. because of program having invalid
number of instructions), tcf_bpf_cfg_cleanup() calls bpf_prog_put(NULL) or
bpf_prog_destroy(NULL). Unless CONFIG_BPF_SYSCALL is unset, this causes
the following error:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
PGD 800000007345a067 P4D 800000007345a067 PUD 340e1067 PMD 0
Oops: 0000 [#1] SMP PTI
Modules linked in: act_bpf(E) ip6table_filter ip6_tables iptable_filter binfmt_misc ext4 mbcache jbd2 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_generic pcbc snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm aesni_intel crypto_simd glue_helper cryptd joydev snd_timer snd virtio_balloon pcspkr soundcore i2c_piix4 nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c ata_generic pata_acpi qxl drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm virtio_blk drm virtio_net virtio_console i2c_core crc32c_intel serio_raw virtio_pci ata_piix libata virtio_ring floppy virtio dm_mirror dm_region_hash dm_log dm_mod [last unloaded: act_bpf]
CPU: 3 PID: 5654 Comm: tc Tainted: G E 4.16.0.bpf_test+ #408
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:__bpf_prog_put+0xc/0xc0
RSP: 0018:ffff9594003ef728 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff9594003ef758 RCX: 0000000000000024
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
R10: 0000000000000220 R11: ffff8a7ab9f17131 R12: 0000000000000000
R13: ffff8a7ab7c3c8e0 R14: 0000000000000001 R15: ffff8a7ab88f1054
FS: 00007fcb2f17c740(0000) GS:ffff8a7abfd80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000020 CR3: 000000007c888006 CR4: 00000000001606e0
Call Trace:
tcf_bpf_cfg_cleanup+0x2f/0x40 [act_bpf]
tcf_bpf_cleanup+0x4c/0x70 [act_bpf]
__tcf_idr_release+0x79/0x140
tcf_bpf_init+0x125/0x330 [act_bpf]
tcf_action_init_1+0x2cc/0x430
? get_page_from_freelist+0x3f0/0x11b0
tcf_action_init+0xd3/0x1b0
tc_ctl_action+0x18b/0x240
rtnetlink_rcv_msg+0x29c/0x310
? _cond_resched+0x15/0x30
? __kmalloc_node_track_caller+0x1b9/0x270
? rtnl_calcit.isra.29+0x100/0x100
netlink_rcv_skb+0xd2/0x110
netlink_unicast+0x17c/0x230
netlink_sendmsg+0x2cd/0x3c0
sock_sendmsg+0x30/0x40
___sys_sendmsg+0x27a/0x290
? mem_cgroup_commit_charge+0x80/0x130
? page_add_new_anon_rmap+0x73/0xc0
? do_anonymous_page+0x2a2/0x560
? __handle_mm_fault+0xc75/0xe20
__sys_sendmsg+0x58/0xa0
do_syscall_64+0x6e/0x1a0
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x7fcb2e58eba0
RSP: 002b:00007ffc93c496c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffc93c497f0 RCX: 00007fcb2e58eba0
RDX: 0000000000000000 RSI: 00007ffc93c49740 RDI: 0000000000000003
RBP: 000000005ac6a646 R08: 0000000000000002 R09: 0000000000000000
R10: 00007ffc93c49120 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc93c49804 R14: 0000000000000001 R15: 000000000066afa0
Code: 5f 00 48 8b 43 20 48 c7 c7 70 2f 7c b8 c7 40 10 00 00 00 00 5b e9 a5 8b 61 00 0f 1f 44 00 00 0f 1f 44 00 00 41 54 55 48 89 fd 53 <48> 8b 47 20 f0 ff 08 74 05 5b 5d 41 5c c3 41 89 f4 0f 1f 44 00
RIP: __bpf_prog_put+0xc/0xc0 RSP: ffff9594003ef728
CR2: 0000000000000020
Fix it in tcf_bpf_cfg_cleanup(), ensuring that bpf_prog_{put,destroy}(f)
is called only when f is not NULL.
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.