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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, syzbot <syzkaller@googlegroups.com>,
	Eric Dumazet <edumazet@google.com>,
	Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH 4.19 35/62] bpf: Make sure mac_header was set before using it
Date: Wed, 27 Jul 2022 18:10:44 +0200	[thread overview]
Message-ID: <20220727161005.574695141@linuxfoundation.org> (raw)
In-Reply-To: <20220727161004.175638564@linuxfoundation.org>

From: Eric Dumazet <edumazet@google.com>

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>
---
 kernel/bpf/core.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -66,11 +66,13 @@ void *bpf_internal_load_pointer_neg_help
 {
 	u8 *ptr = NULL;
 
-	if (k >= SKF_NET_OFF)
+	if (k >= SKF_NET_OFF) {
 		ptr = skb_network_header(skb) + k - SKF_NET_OFF;
-	else if (k >= SKF_LL_OFF)
+	} else if (k >= SKF_LL_OFF) {
+		if (unlikely(!skb_mac_header_was_set(skb)))
+			return NULL;
 		ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
-
+	}
 	if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
 		return ptr;
 



  parent reply	other threads:[~2022-07-27 16:35 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 16:10 [PATCH 4.19 00/62] 4.19.254-rc1 review Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 01/62] riscv: add as-options for modules with assembly compontents Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 02/62] xen/gntdev: Ignore failure to unmap INVALID_GRANT_HANDLE Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 03/62] xfrm: xfrm_policy: fix a possible double xfrm_pols_put() in xfrm_bundle_lookup() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 04/62] power/reset: arm-versatile: Fix refcount leak in versatile_reboot_probe Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 05/62] pinctrl: ralink: Check for null return of devm_kcalloc Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 06/62] perf/core: Fix data race between perf_event_set_output() and perf_mmap_close() Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 07/62] ip: Fix data-races around sysctl_ip_fwd_use_pmtu Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 08/62] ip: Fix data-races around sysctl_ip_nonlocal_bind Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 09/62] ip: Fix a data-race around sysctl_fwmark_reflect Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 10/62] tcp/dccp: Fix a data-race around sysctl_tcp_fwmark_accept Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 11/62] tcp: Fix data-races around sysctl_tcp_mtu_probing Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 12/62] tcp: Fix a data-race around sysctl_tcp_probe_threshold Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 13/62] tcp: Fix a data-race around sysctl_tcp_probe_interval Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 14/62] i2c: cadence: Change large transfer count reset logic to be unconditional Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 15/62] net: stmmac: fix dma queue left shift overflow issue Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 16/62] net/tls: Fix race in TLS device down flow Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 17/62] igmp: Fix data-races around sysctl_igmp_llm_reports Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 18/62] igmp: Fix a data-race around sysctl_igmp_max_memberships Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 19/62] tcp: Fix data-races around sysctl_tcp_reordering Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 20/62] tcp: Fix data-races around some timeout sysctl knobs Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 21/62] tcp: Fix a data-race around sysctl_tcp_notsent_lowat Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 22/62] tcp: Fix a data-race around sysctl_tcp_tw_reuse Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 23/62] tcp: Fix data-races around sysctl_tcp_fastopen Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 24/62] be2net: Fix buffer overflow in be_get_module_eeprom Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 25/62] tcp: Fix a data-race around sysctl_tcp_early_retrans Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 26/62] tcp: Fix data-races around sysctl_tcp_recovery Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 27/62] tcp: Fix a data-race around sysctl_tcp_thin_linear_timeouts Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 28/62] tcp: Fix data-races around sysctl_tcp_slow_start_after_idle Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 29/62] tcp: Fix a data-race around sysctl_tcp_retrans_collapse Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 30/62] tcp: Fix a data-race around sysctl_tcp_stdurg Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 31/62] tcp: Fix a data-race around sysctl_tcp_rfc1337 Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 32/62] tcp: Fix data-races around sysctl_tcp_max_reordering Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 33/62] Revert "Revert "char/random: silence a lockdep splat with printk()"" Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 34/62] mm/mempolicy: fix uninit-value in mpol_rebind_policy() Greg Kroah-Hartman
2022-07-27 16:10 ` Greg Kroah-Hartman [this message]
2022-07-27 16:10 ` [PATCH 4.19 36/62] drm/tilcdc: Remove obsolete crtc_mode_valid() hack Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 37/62] tilcdc: tilcdc_external: fix an incorrect NULL check on list iterator Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 38/62] HID: multitouch: simplify the application retrieval Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 39/62] HID: multitouch: Lenovo X1 Tablet Gen3 trackpoint and buttons Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 40/62] HID: multitouch: add support for the Smart Tech panel Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 41/62] HID: add ALWAYS_POLL quirk to lenovo pixart mouse Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 42/62] dlm: fix pending remove if msg allocation fails Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 43/62] ima: remove the IMA_TEMPLATE Kconfig option Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 44/62] ALSA: memalloc: Align buffer allocations in page size Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 45/62] Bluetooth: Add bt_skb_sendmsg helper Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 46/62] Bluetooth: Add bt_skb_sendmmsg helper Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 47/62] Bluetooth: SCO: Replace use of memcpy_from_msg with bt_skb_sendmsg Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 48/62] Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 49/62] Bluetooth: Fix passing NULL to PTR_ERR Greg Kroah-Hartman
2022-07-27 16:10 ` [PATCH 4.19 50/62] Bluetooth: SCO: Fix sco_send_frame returning skb->len Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 51/62] Bluetooth: Fix bt_skb_sendmmsg not allocating partial chunks Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 52/62] serial: mvebu-uart: correctly report configured baudrate value Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 53/62] tty: drivers/tty/, stop using tty_schedule_flip() Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 54/62] tty: the rest, " Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 55/62] tty: drop tty_schedule_flip() Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 56/62] tty: extract tty_flip_buffer_commit() from tty_flip_buffer_push() Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 57/62] tty: use new tty_insert_flip_string_and_push_buffer() in pty_write() Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 58/62] net: usb: ax88179_178a needs FLAG_SEND_ZLP Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 59/62] PCI: hv: Fix multi-MSI to allow more than one MSI vector Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 60/62] PCI: hv: Fix hv_arch_irq_unmask() for multi-MSI Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 61/62] PCI: hv: Reuse existing IRTE allocation in compose_msi_msg() Greg Kroah-Hartman
2022-07-27 16:11 ` [PATCH 4.19 62/62] PCI: hv: Fix interrupt mapping for multi-MSI Greg Kroah-Hartman
2022-07-28  9:42 ` [PATCH 4.19 00/62] 4.19.254-rc1 review Pavel Machek
2022-07-28  9:45 ` Naresh Kamboju
2022-07-28 14:31 ` Sudip Mukherjee (Codethink)
2022-07-28 14:32 ` Jon Hunter
2022-07-28 14:51 ` Shuah Khan
2022-07-28 22:58 ` Guenter Roeck

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