Re: [tip:x86/pti] x86/asm: Pad assembly functions with INT3 instructions

From: Mike Galbraith
Date: Sun Jun 17 2018 - 07:41:36 EST

On Mon, 2018-05-14 at 05:53 -0700, tip-bot for Alexey Dobriyan wrote:
> Commit-ID: 51bad67ffbce0aaa44579f84ef5d05597054ec6a
> Gitweb: https://git.kernel.org/tip/51bad67ffbce0aaa44579f84ef5d05597054ec6a
> Author: Alexey Dobriyan <adobriyan@xxxxxxxxx>
> AuthorDate: Tue, 8 May 2018 00:37:55 +0300
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> CommitDate: Mon, 14 May 2018 11:43:03 +0200
>
> x86/asm: Pad assembly functions with INT3 instructions
>
> Use INT3 instead of NOP. All that padding between functions is
> an illegal area, no legitimate code should jump into it.

Is dinky patchlet suggesting cryptomgr is being naughty?

(revert silences spew, but..)

...
[ 21.041608] int3: 0000 [#1] SMP PTI
[ 21.041754] CPU: 3 PID: 935 Comm: cryptomgr_test Tainted: G E 4.17.0.g075a1d3-tip-default #146
[ 21.041888] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013
[ 21.042035] RIP: 0010:crypto_aegis128_aesni_enc_tail+0x74/0x80 [aegis128_aesni]
[ 21.042171] Code: 38 dc ca 66 0f 38 dc d3 66 0f 38 dc de 66 0f ef e5 f3 0f 7f 27 f3 0f 7f 47 10 f3 0f 7f 4f 20 f3 0f 7f 57 30 f3 0f 7f 5f 40 cc <cc> cc cc cc cc cc cc cc cc cc cc cc 48 83 fe 10 0f 82 c3 03 00 00
[ 21.042333] RSP: 0018:ffff963f81ee79b8 EFLAGS: 00000246
[ 21.042485] RAX: ffffffffc0985950 RBX: 0000000000000001 RCX: ffff8a3ab90d6000
[ 21.042640] RDX: ffff8a3ab90d6000 RSI: 0000000000000001 RDI: ffff963f81ee7af0
[ 21.042792] RBP: ffff963f81ee7a90 R08: 0000000000000001 R09: ffff8a3ab90d6000
[ 21.042953] R10: c1267690ad7d2d9e R11: 00000000ffffffe0 R12: ffff8a3ab90d6000
[ 21.043100] R13: ffffffffc0987040 R14: ffff963f81ee7af0 R15: ffff8a3ab90d6000
[ 21.043250] FS: 0000000000000000(0000) GS:ffff8a3adecc0000(0000) knlGS:0000000000000000
[ 21.043405] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 21.043554] CR2: 00007f2e169c4010 CR3: 00000001f700a005 CR4: 00000000001606e0
[ 21.043704] Call Trace:
[ 21.043854] ? crypto_aegis128_aesni_process_crypt+0x8a/0xc0 [aegis128_aesni]
[ 21.044004] ? crypto_aegis128_aesni_crypt+0x238/0x440 [aegis128_aesni]
[ 21.044156] ? crypto_aegis128_aesni_crypt+0x238/0x440 [aegis128_aesni]
[ 21.044311] ? crypto_aegis128_aesni_encrypt+0x62/0xb0 [aegis128_aesni]
[ 21.044454] ? crypto_aegis128_aesni_encrypt+0x62/0xb0 [aegis128_aesni]
[ 21.044597] ? crypto_aead_setauthsize+0x23/0x40
[ 21.044739] ? __test_aead+0x632/0x15d0
[ 21.044884] ? crypto_aegis128_aesni_crypt+0x440/0x440 [aegis128_aesni]
[ 21.045026] ? __test_aead+0x632/0x15d0
[ 21.045167] ? crypto_alloc_tfm+0x52/0xf0
[ 21.045308] ? crypto_acomp_scomp_free_ctx+0x30/0x30
[ 21.045449] ? crypto_create_tfm+0x32/0xe0
[ 21.045594] ? crypto_acomp_scomp_free_ctx+0x30/0x30
[ 21.045734] ? crypto_acomp_scomp_free_ctx+0x30/0x30
[ 21.045877] ? test_aead+0x21/0xa0
[ 21.046015] ? alg_test_aead+0x3f/0xa0
[ 21.046154] ? alg_test.part.13+0x170/0x370
[ 21.046291] ? pick_next_task_fair+0x134/0x5d0
[ 21.046426] ? __switch_to+0x92/0x4b0
[ 21.046565] ? finish_task_switch+0x7f/0x2d0
[ 21.046701] ? __schedule+0x2b8/0x860
[ 21.046833] ? crypto_acomp_scomp_free_ctx+0x30/0x30
[ 21.046963] ? cryptomgr_test+0x40/0x50
[ 21.047092] ? kthread+0x11e/0x140
[ 21.047221] ? kthread_associate_blkcg+0xb0/0xb0
[ 21.047350] ? ret_from_fork+0x3a/0x50
[ 21.047478] Modules linked in: aegis128_aesni(E+) snd_timer(E) crct10dif_pclmul(E) r8169(E) snd(E) crc32_pclmul(E) mii(E) iTCO_wdt(E) ghash_clmulni_intel(E) iTCO_vendor_support(E) pcbc(E) gpio_ich(E) aesni_intel(E) soundcore(E) aes_x86_64(E) lpc_ich(E) crypto_simd(E) mei_me(E) cryptd(E) mfd_core(E) i2c_i801(E) mei(E) glue_helper(E) pcspkr(E) thermal(E) intel_smartconnect(E) fan(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) sch_fq_codel(E) sr_mod(E) cdrom(E) hid_logitech_hidpp(E) hid_logitech_dj(E) uas(E) usb_storage(E) hid_generic(E) usbhid(E) nouveau(E) wmi(E) i2c_algo_bit(E) drm_kms_helper(E) syscopyarea(E) xhci_pci(E) sysfillrect(E) sysimgblt(E) fb_sys_fops(E) ahci(E) ttm(E) ehci_pci(E) libahci(E) xhci_hcd(E) ehci_hcd(E) libata(E) drm(E) usbcore(E) video(E) button(E) sd_mod(E)
[ 21.048064] vfat(E) fat(E) virtio_blk(E) virtio_mmio(E) virtio_pci(E) virtio_ring(E) virtio(E) ext4(E) crc32c_intel(E) crc16(E) mbcache(E) jbd2(E) loop(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) efivarfs(E)
[ 21.048396] Dumping ftrace buffer:
[ 21.048556] (ftrace buffer empty)
[ 21.048726] ---[ end trace 8cdd2dd0a107e807 ]---
[ 21.048901] RIP: 0010:crypto_aegis128_aesni_enc_tail+0x74/0x80 [aegis128_aesni]
[ 21.049051] Code: 38 dc ca 66 0f 38 dc d3 66 0f 38 dc de 66 0f ef e5 f3 0f 7f 27 f3 0f 7f 47 10 f3 0f 7f 4f 20 f3 0f 7f 57 30 f3 0f 7f 5f 40 cc <cc> cc cc cc cc cc cc cc cc cc cc cc 48 83 fe 10 0f 82 c3 03 00 00
[ 21.049224] RSP: 0018:ffff963f81ee79b8 EFLAGS: 00000246
[ 21.049390] RAX: ffffffffc0985950 RBX: 0000000000000001 RCX: ffff8a3ab90d6000
[ 21.049579] RDX: ffff8a3ab90d6000 RSI: 0000000000000001 RDI: ffff963f81ee7af0
[ 21.049782] RBP: ffff963f81ee7a90 R08: 0000000000000001 R09: ffff8a3ab90d6000
[ 21.049978] R10: c1267690ad7d2d9e R11: 00000000ffffffe0 R12: ffff8a3ab90d6000
[ 21.050179] R13: ffffffffc0987040 R14: ffff963f81ee7af0 R15: ffff8a3ab90d6000
[ 21.050377] FS: 0000000000000000(0000) GS:ffff8a3adecc0000(0000) knlGS:0000000000000000
[ 21.050579] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 21.050777] CR2: 00007f2e169c4010 CR3: 00000001f700a005 CR4: 00000000001606e0
[ 21.050981] BUG: sleeping function called from invalid context at ./include/linux/percpu-rwsem.h:34
[ 21.051183] in_atomic(): 1, irqs_disabled(): 0, pid: 935, name: cryptomgr_test
[ 21.051390] CPU: 3 PID: 935 Comm: cryptomgr_test Tainted: G D E 4.17.0.g075a1d3-tip-default #146
[ 21.051592] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013
[ 21.051799] Call Trace:
[ 21.052002] dump_stack+0x85/0xcb
[ 21.052207] ___might_sleep+0xd8/0x130
[ 21.052412] exit_signals+0x21/0x1c0
[ 21.052612] do_exit+0xa0/0xb60
[ 21.052808] ? cryptomgr_test+0x40/0x50
[ 21.052999] ? kthread+0x11e/0x140
[ 21.053176] rewind_stack_do_exit+0x17/0x20
[ 21.053354] note: cryptomgr_test[935] exited with preempt_count 2
...
[ 200.214958] WARNING: CPU: 7 PID: 601 at crypto/algapi.c:369 crypto_wait_for_test+0x4c/0x60
[ 200.214960] Modules linked in: fuse(E) devlink(E) ebtable_filter(E) ebtables(E) xt_comment(E) xt_physdev(E) br_netfilter(E) nfnetlink_cthelper(E) nfnetlink(E) af_packet(E) bridge(E) stp(E) llc(E) iscsi_ibft(E) iscsi_boot_sysfs(E) msr(E) ip6t_REJECT(E) nf_conntrack_ipv6(E) nf_defrag_ipv6(E) ipt_REJECT(E) xt_pkttype(E) xt_tcpudp(E) iptable_filter(E) bpfilter(E) ip6table_mangle(E) nf_conntrack_netbios_ns(E) nf_conntrack_broadcast(E) nf_conntrack_ipv4(E) nf_defrag_ipv4(E) ip_tables(E) xt_conntrack(E) nf_conntrack(E) libcrc32c(E) ip6table_filter(E) ip6_tables(E) x_tables(E) nls_iso8859_1(E) nls_cp437(E) joydev(E) snd_hda_codec_hdmi(E) snd_hda_codec_realtek(E) snd_hda_codec_generic(E) snd_hda_intel(E) snd_hda_codec(E) snd_hda_core(E) snd_hwdep(E) snd_pcm(E) aegis128_aesni(E+) snd_timer(E) crct10dif_pclmul(E)
[ 200.215086] r8169(E) snd(E) crc32_pclmul(E) mii(E) iTCO_wdt(E) ghash_clmulni_intel(E) iTCO_vendor_support(E) pcbc(E) gpio_ich(E) aesni_intel(E) soundcore(E) aes_x86_64(E) lpc_ich(E) crypto_simd(E) mei_me(E) cryptd(E) mfd_core(E) i2c_i801(E) mei(E) glue_helper(E) pcspkr(E) thermal(E) intel_smartconnect(E) fan(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) sch_fq_codel(E) sr_mod(E) cdrom(E) hid_logitech_hidpp(E) hid_logitech_dj(E) uas(E) usb_storage(E) hid_generic(E) usbhid(E) nouveau(E) wmi(E) i2c_algo_bit(E) drm_kms_helper(E) syscopyarea(E) xhci_pci(E) sysfillrect(E) sysimgblt(E) fb_sys_fops(E) ahci(E) ttm(E) ehci_pci(E) libahci(E) xhci_hcd(E) ehci_hcd(E) libata(E) drm(E) usbcore(E) video(E) button(E) sd_mod(E) vfat(E) fat(E) virtio_blk(E) virtio_mmio(E) virtio_pci(E) virtio_ring(E)
[ 200.215188] virtio(E) ext4(E) crc32c_intel(E) crc16(E) mbcache(E) jbd2(E) loop(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) efivarfs(E)
[ 200.215216] CPU: 7 PID: 601 Comm: systemd-udevd Kdump: loaded Tainted: G D W E 4.17.0.g075a1d3-tip-default #146
[ 200.215222] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013
[ 200.215230] RIP: 0010:crypto_wait_for_test+0x4c/0x60
[ 200.215234] Code: c0 75 2b 48 8d bb b8 00 00 00 31 f6 e8 2d fe ff ff 48 8d bb a8 01 00 00 e8 61 13 40 00 85 c0 75 09 48 89 df 5b e9 54 e5 ff ff <0f> 0b eb f3 0f 0b eb ef 66 90 66 2e 0f 1f 84 00 00 00 00 00 0f 1f
[ 200.215303] RSP: 0018:ffff963f826cfc88 EFLAGS: 00010286
[ 200.215310] RAX: 00000000fffffe00 RBX: ffff8a3ab18cb400 RCX: 0000000000000002
[ 200.215316] RDX: 0000000000000000 RSI: 000000009d980d40 RDI: ffff8a3ab18cb5b0
[ 200.215321] RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000024f
[ 200.215327] R10: 0000000000000355 R11: 00000000003d0900 R12: 0000000000000000
[ 200.215333] R13: ffffffffc0988000 R14: 0000000000000002 R15: ffff8a3ab02a7f80
[ 200.215340] FS: 00007fe89d980d40(0000) GS:ffff8a3adedc0000(0000) knlGS:0000000000000000
[ 200.215346] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 200.215351] CR2: 00007f83fc010e08 CR3: 00000003f1abe006 CR4: 00000000001606e0
[ 200.215356] Call Trace:
[ 200.215367] crypto_register_alg+0x52/0x60
[ 200.215376] crypto_register_aeads+0x35/0xa0
[ 200.215383] ? 0xffffffffc0325000
[ 200.215391] do_one_initcall+0x46/0x1e9
[ 200.215400] ? __vunmap+0x76/0xb0
[ 200.215408] do_init_module+0x5b/0x203
[ 200.215415] load_module+0x19d3/0x1f50
[ 200.215422] ? __do_sys_finit_module+0xb7/0xd0
[ 200.215427] __do_sys_finit_module+0xb7/0xd0
[ 200.215433] do_syscall_64+0x60/0x180
[ 200.215438] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 200.215442] RIP: 0033:0x7fe89c807139
[ 200.215444] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 2f 0d 2c 00 f7 d8 64 89 01 48
[ 200.215528] RSP: 002b:00007fff4d130458 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[ 200.215549] RAX: ffffffffffffffda RBX: 000055b492f18880 RCX: 00007fe89c807139
[ 200.215551] RDX: 0000000000000000 RSI: 00007fe89d14383d RDI: 0000000000000016
[ 200.215554] RBP: 00007fe89d14383d R08: 0000000000000000 R09: 000055b492ecd480
[ 200.215581] R10: 0000000000000016 R11: 0000000000000246 R12: 0000000000020000
[ 200.215583] R13: 000055b492fa55e0 R14: 0000000000000000 R15: 0000000000000000
[ 200.215587] ---[ end trace 8cdd2dd0a107e808 ]---