linux-kernel - Re: ethtool_get_rxnfc: Buffer overflow detected (8

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Message-ID: <c428cdd7-cba2-b292-4fe0-5b71c87558de@infradead.org>
Date:   Sat, 18 Sep 2021 17:52:00 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Kelly Anderson <kelly@...ka.com>, linux-kernel@...r.kernel.org,
        Netdev <netdev@...r.kernel.org>
Subject: Re: ethtool_get_rxnfc: Buffer overflow detected (8 < 192)!

[adding netdev]

On 9/18/21 5:16 PM, Kelly Anderson wrote:
> New patches in 5.14.6 cause a problem in ethtool_get_rxnfc.
> 
> It seems someone has allocated a variable length struct @958:ioctl.c: struct ethtool_rxnfc info.
> Unfortunately depending on the calls being made the struct cannot hold the variable length part of the data.
> Luckily the error checking caught this, otherwise it would be messing up the stack.
> 
> 
> Sep 18 15:11:27 bbb.internal kernel: Buffer overflow detected (8 < 192)!
> Sep 18 15:11:27 bbb.internal kernel: WARNING: CPU: 4 PID: 1434 at include/linux/thread_info.h:200 ethtool_rxnfc_copy_to_user+0x26/0xa0
> Sep 18 15:11:27 bbb.internal kernel: Modules linked in: xt_CHECKSUM xt_MASQUERADE ipt_REJECT nf_reject_ipv4 ip6table_mangle ip6table_nat iptable_mangle iptable_nat nf_nat ip6table_filter ip6_tables xt_tcpudp xt_set xt_LOG nf_log_syslog xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter bpfilter ip_set_hash_ipport ip_set_list_set ip_set_hash_net ip_set_hash_ip ip_set nfnetlink amdgpu iommu_v2 gpu_sched snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi wmi_bmof mxm_wmi sp5100_tco crct10dif_pclmul ghash_clmulni_intel pcspkr fam15h_power k10temp radeon ixgbe i2c_piix4 ptp i2c_algo_bit drm_ttm_helper snd_hda_intel pps_core ttm snd_intel_dspcfg mdio snd_intel_sdw_acpi dca drm_kms_helper snd_hda_codec xhci_pci xhci_pci_renesas snd_hda_core cec snd_pcm fb_sys_fops snd_timer syscopyarea sysfillrect snd sysimgblt soundcore wmi evdev sch_fq_codel xt_limit vhost_net vhost vhost_iotlb tap tun sha512_ssse3 sha1_ssse3 sg rpcsec_gss_krb5 r8169 realtek mdio_devres libphy macvlan
> Sep 18 15:11:27 bbb.internal kernel:  kvm_amd ccp rng_core kvm irqbypass it87 hwmon_vid hwmon msr ftdi_sio cpuid camellia_aesni_avx_x86_64 camellia_x86_64 br_netfilter bridge stp llc aesni_intel crypto_simd cryptd drm nfsd configfs ip_tables x_tables
> Sep 18 15:11:27 bbb.internal kernel: CPU: 4 PID: 1434 Comm: nmbd Tainted: G                T 5.14.6 #1
> Sep 18 15:11:27 bbb.internal kernel: Hardware name: To be filled by O.E.M. To be filled by O.E.M./SABERTOOTH 990FX R2.0, BIOS 2901 05/04/2016
> Sep 18 15:11:27 bbb.internal kernel: RIP: 0010:ethtool_rxnfc_copy_to_user+0x26/0xa0
> Sep 18 15:11:27 bbb.internal kernel: Code: ff 0f 1f 00 41 55 65 48 8b 04 25 00 6d 01 00 41 54 55 53 f6 40 10 02 75 23 be 08 00 00 00 48 c7 c7 68 16 30 aa e8 01 85 13 00 <0f> 0b 41 bc f2 ff ff ff 5b 44 89 e0 5d 41 5c 41 5d c3 48 89 fb 49
> Sep 18 15:11:27 bbb.internal kernel: RSP: 0018:ffffb9ca819bbb10 EFLAGS: 00010282
> Sep 18 15:11:27 bbb.internal kernel: RAX: 0000000000000000 RBX: ffffffffc071a440 RCX: 0000000000000027
> Sep 18 15:11:27 bbb.internal kernel: RDX: ffff9d78ded17508 RSI: 0000000000000001 RDI: ffff9d78ded17500
> Sep 18 15:11:27 bbb.internal kernel: RBP: ffffb9ca819bbb40 R08: 0000000000000000 R09: ffffb9ca819bb948
> Sep 18 15:11:27 bbb.internal kernel: R10: ffffb9ca819bb940 R11: ffffffffaa6beda8 R12: 0000000000000000
> Sep 18 15:11:27 bbb.internal kernel: R13: 00007ffe1b458980 R14: 0000000000000000 R15: ffff9d71c7e08000
> Sep 18 15:11:27 bbb.internal kernel: FS:  00007fcd84c55a40(0000) GS:ffff9d78ded00000(0000) knlGS:0000000000000000
> Sep 18 15:11:27 bbb.internal kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> Sep 18 15:11:27 bbb.internal kernel: CR2: 00005576720f14d8 CR3: 0000000243892000 CR4: 00000000000406e0
> Sep 18 15:11:27 bbb.internal kernel: Call Trace:
> Sep 18 15:11:27 bbb.internal kernel:  ethtool_get_rxnfc+0xce/0x1b0
> Sep 18 15:11:27 bbb.internal kernel:  dev_ethtool+0xc26/0x2d90
> Sep 18 15:11:27 bbb.internal kernel:  ? inet_ioctl+0xe5/0x210
> Sep 18 15:11:27 bbb.internal kernel:  dev_ioctl+0x188/0x490
> Sep 18 15:11:27 bbb.internal kernel:  sock_do_ioctl+0xe9/0x180
> Sep 18 15:11:27 bbb.internal kernel:  sock_ioctl+0x273/0x370
> Sep 18 15:11:27 bbb.internal kernel:  __x64_sys_ioctl+0x7c/0xb0
> Sep 18 15:11:27 bbb.internal kernel:  do_syscall_64+0x64/0x90
> Sep 18 15:11:27 bbb.internal kernel:  ? sock_alloc_file+0x56/0xa0
> Sep 18 15:11:27 bbb.internal kernel:  ? get_vtime_delta+0xa/0xb0
> Sep 18 15:11:27 bbb.internal kernel:  ? vtime_user_enter+0x17/0x70
> Sep 18 15:11:27 bbb.internal kernel:  ? __context_tracking_enter+0x5c/0x60
> Sep 18 15:11:27 bbb.internal kernel:  ? syscall_exit_to_user_mode+0x39/0x40
> Sep 18 15:11:27 bbb.internal kernel:  ? do_syscall_64+0x71/0x90
> Sep 18 15:11:27 bbb.internal kernel:  ? syscall_exit_to_user_mode+0x39/0x40
> Sep 18 15:11:27 bbb.internal kernel:  ? do_syscall_64+0x71/0x90
> Sep 18 15:11:27 bbb.internal kernel:  ? vtime_user_enter+0x17/0x70
> Sep 18 15:11:27 bbb.internal kernel:  ? __context_tracking_enter+0x5c/0x60
> Sep 18 15:11:27 bbb.internal kernel:  entry_SYSCALL_64_after_hwframe+0x44/0xae
> Sep 18 15:11:27 bbb.internal kernel: RIP: 0033:0x7fcd84b1a767
> Sep 18 15:11:27 bbb.internal kernel: Code: 3c 1c e8 2c ff ff ff 85 c0 79 97 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 99 16 0f 00 f7 d8 64 89 01 48
> Sep 18 15:11:27 bbb.internal kernel: RSP: 002b:00007ffe1b458938 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> Sep 18 15:11:27 bbb.internal kernel: RAX: ffffffffffffffda RBX: 00005576720f0160 RCX: 00007fcd84b1a767
> Sep 18 15:11:27 bbb.internal kernel: RDX: 00007ffe1b458950 RSI: 0000000000008946 RDI: 000000000000000f
> Sep 18 15:11:27 bbb.internal kernel: RBP: 00007ffe1b458a50 R08: 0000000000000000 R09: 00007fcd84b6e070
> Sep 18 15:11:27 bbb.internal kernel: R10: 0000000000000040 R11: 0000000000000246 R12: 00007ffe1b458ee8
> Sep 18 15:11:27 bbb.internal kernel: R13: 00005576702c9649 R14: 00007fcd85187c40 R15: 000055767030a350
> Sep 18 15:11:27 bbb.internal kernel: ---[ end trace d48f50afc5752bb2 ]---
> 
> 
> 


-- 
~Randy
Reported-by: Randy Dunlap <rdunlap@...radead.org>
https://people.kernel.org/tglx/notes-about-netiquette