From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sergey Marinkevich <sergey.marinkevich@eltex-co.ru>,
Florian Westphal <fw@strlen.de>,
Pablo Neira Ayuso <pablo@netfilter.org>,
Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 63/64] netfilter: nft_exthdr: fix endianness of tcp option cast
Date: Tue, 24 Aug 2021 13:04:56 -0400 [thread overview]
Message-ID: <20210824170457.710623-64-sashal@kernel.org> (raw)
In-Reply-To: <20210824170457.710623-1-sashal@kernel.org>
From: Sergey Marinkevich <sergey.marinkevich@eltex-co.ru>
[ Upstream commit 2e34328b396a69b73661ba38d47d92b7cf21c2c4 ]
I got a problem on MIPS with Big-Endian is turned on: every time when
NF trying to change TCP MSS it returns because of new.v16 was greater
than old.v16. But real MSS was 1460 and my rule was like this:
add rule table chain tcp option maxseg size set 1400
And 1400 is lesser that 1460, not greater.
Later I founded that main causer is cast from u32 to __be16.
Debugging:
In example MSS = 1400(HEX: 0x578). Here is representation of each byte
like it is in memory by addresses from left to right(e.g. [0x0 0x1 0x2
0x3]). LE — Little-Endian system, BE — Big-Endian, left column is type.
LE BE
u32: [78 05 00 00] [00 00 05 78]
As you can see, u32 representation will be casted to u16 from different
half of 4-byte address range. But actually nf_tables uses registers and
store data of various size. Actually TCP MSS stored in 2 bytes. But
registers are still u32 in definition:
struct nft_regs {
union {
u32 data[20];
struct nft_verdict verdict;
};
};
So, access like regs->data[priv->sreg] exactly u32. So, according to
table presents above, per-byte representation of stored TCP MSS in
register will be:
LE BE
(u32)regs->data[]: [78 05 00 00] [05 78 00 00]
^^ ^^
We see that register uses just half of u32 and other 2 bytes may be
used for some another data. But in nft_exthdr_tcp_set_eval() it casted
just like u32 -> __be16:
new.v16 = src
But u32 overfill __be16, so it get 2 low bytes. For clarity draw
one more table(<xx xx> means that bytes will be used for cast).
LE BE
u32: [<78 05> 00 00] [00 00 <05 78>]
(u32)regs->data[]: [<78 05> 00 00] [05 78 <00 00>]
As you can see, for Little-Endian nothing changes, but for Big-endian we
take the wrong half. In my case there is some other data instead of
zeros, so new MSS was wrongly greater.
For shooting this bug I used solution for ports ranges. Applying of this
patch does not affect Little-Endian systems.
Signed-off-by: Sergey Marinkevich <sergey.marinkevich@eltex-co.ru>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nft_exthdr.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index a301d3bbd3fa..e73a1503e8d7 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -138,7 +138,6 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
unsigned int i, optl, tcphdr_len, offset;
struct tcphdr *tcph;
u8 *opt;
- u32 src;
tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len);
if (!tcph)
@@ -147,7 +146,6 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
opt = (u8 *)tcph;
for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) {
union {
- u8 octet;
__be16 v16;
__be32 v32;
} old, new;
@@ -168,13 +166,13 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
if (!tcph)
return;
- src = regs->data[priv->sreg];
offset = i + priv->offset;
switch (priv->len) {
case 2:
old.v16 = get_unaligned((u16 *)(opt + offset));
- new.v16 = src;
+ new.v16 = (__force __be16)nft_reg_load16(
+ ®s->data[priv->sreg]);
switch (priv->type) {
case TCPOPT_MSS:
@@ -192,7 +190,7 @@ static void nft_exthdr_tcp_set_eval(const struct nft_expr *expr,
old.v16, new.v16, false);
break;
case 4:
- new.v32 = src;
+ new.v32 = regs->data[priv->sreg];
old.v32 = get_unaligned((u32 *)(opt + offset));
if (old.v32 == new.v32)
--
2.30.2
next prev parent reply other threads:[~2021-08-24 17:34 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 17:03 [PATCH 4.14 00/64] 4.14.245-rc1 review Sasha Levin
2021-08-24 17:03 ` [PATCH 4.14 01/64] iio: humidity: hdc100x: Add margin to the conversion time Sasha Levin
2021-08-24 17:03 ` [PATCH 4.14 02/64] iio: adc: Fix incorrect exit of for-loop Sasha Levin
2021-08-24 17:03 ` [PATCH 4.14 03/64] ASoC: intel: atom: Fix reference to PCM buffer address Sasha Levin
2021-08-24 17:03 ` [PATCH 4.14 04/64] i2c: dev: zero out array used for i2c reads from userspace Sasha Levin
2021-08-24 17:03 ` [PATCH 4.14 05/64] ACPI: NFIT: Fix support for virtual SPA ranges Sasha Levin
2021-08-24 17:03 ` [PATCH 4.14 06/64] ASoC: cs42l42: Correct definition of ADC Volume control Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 07/64] ASoC: cs42l42: Don't allow SND_SOC_DAIFMT_LEFT_J Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 08/64] ASoC: cs42l42: Fix inversion of ADC Notch Switch control Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 09/64] ASoC: cs42l42: Remove duplicate control for WNF filter frequency Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 10/64] net: dsa: mt7530: add the missing RxUnicast MIB counter Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 11/64] ppp: Fix generating ifname when empty IFLA_IFNAME is specified Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 12/64] psample: Add a fwd declaration for skbuff Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 13/64] net: Fix memory leak in ieee802154_raw_deliver Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 14/64] net: bridge: fix memleak in br_add_if() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 15/64] tcp_bbr: fix u32 wrap bug in round logic if bbr_init() called after 2B packets Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 16/64] xen/events: Fix race in set_evtchn_to_irq Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 17/64] vsock/virtio: avoid potential deadlock when vsock device remove Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 18/64] powerpc/kprobes: Fix kprobe Oops happens in booke Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 19/64] x86/tools: Fix objdump version check again Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 20/64] x86/resctrl: Fix default monitoring groups reporting Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 21/64] PCI/MSI: Enable and mask MSI-X early Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 22/64] PCI/MSI: Do not set invalid bits in MSI mask Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 23/64] PCI/MSI: Correct misleading comments Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 24/64] PCI/MSI: Use msi_mask_irq() in pci_msi_shutdown() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 25/64] PCI/MSI: Protect msi_desc::masked for multi-MSI Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 26/64] PCI/MSI: Mask all unused MSI-X entries Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 27/64] PCI/MSI: Enforce that MSI-X table entry is masked for update Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 28/64] PCI/MSI: Enforce MSI[X] entry updates to be visible Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 29/64] vmlinux.lds.h: Handle clang's module.{c,d}tor sections Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 30/64] mac80211: drop data frames without key on encrypted links Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 31/64] KVM: nSVM: always intercept VMLOAD/VMSAVE when nested (CVE-2021-3656) Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 32/64] KVM: nSVM: avoid picking up unsupported bits from L2 in int_ctl (CVE-2021-3653) Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 33/64] x86/fpu: Make init_fpstate correct with optimized XSAVE Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 34/64] ath: Use safer key clearing with key cache entries Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 35/64] ath9k: Clear key cache explicitly on disabling hardware Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 36/64] ath: Export ath_hw_keysetmac() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 37/64] ath: Modify ath_key_delete() to not need full key entry Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 38/64] ath9k: Postpone key cache entry deletion for TXQ frames reference it Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 39/64] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 40/64] ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218 Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 41/64] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 42/64] scsi: megaraid_mm: Fix end of loop tests for list_for_each_entry() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 43/64] scsi: scsi_dh_rdac: Avoid crash during rdac_bus_attach() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 44/64] scsi: core: Avoid printing an error if target_alloc() returns -ENXIO Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 45/64] ARM: dts: nomadik: Fix up interrupt controller node names Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 46/64] net: usb: lan78xx: don't modify phy_device state concurrently Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 47/64] Bluetooth: hidp: use correct wait queue when removing ctrl_wait Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 48/64] dccp: add do-while-0 stubs for dccp_pr_debug macros Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 49/64] vhost: Fix the calculation in vhost_overflow() Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 50/64] bnxt: don't lock the tx queue from napi poll Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 51/64] net: 6pack: fix slab-out-of-bounds in decode_data Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 52/64] ptp_pch: Restore dependency on PCI Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 53/64] net: qlcnic: add missed unlock in qlcnic_83xx_flash_read32 Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 54/64] net: mdio-mux: Don't ignore memory allocation errors Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 55/64] net: mdio-mux: Handle -EPROBE_DEFER correctly Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 56/64] mmc: dw_mmc: Fix hang on data CRC error Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 57/64] ALSA: hda - fix the 'Capture Switch' value change notifications Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 58/64] ipack: tpci200: fix many double free issues in tpci200_pci_probe Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 59/64] btrfs: prevent rename2 from exchanging a subvol with a directory from different parents Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 60/64] ASoC: intel: atom: Fix breakage for PCM buffer address setup Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 61/64] locks: print a warning when mount fails due to lack of "mand" support Sasha Levin
2021-08-24 17:04 ` [PATCH 4.14 62/64] fs: warn about impending deprecation of mandatory locks Sasha Levin
2021-08-24 17:04 ` Sasha Levin [this message]
2021-08-24 17:04 ` [PATCH 4.14 64/64] Linux 4.14.245-rc1 Sasha Levin
2021-08-25 20:26 ` [PATCH 4.14 00/64] 4.14.245-rc1 review Guenter Roeck
2021-08-25 21:04 ` Daniel Díaz
2021-08-26 1:01 ` Samuel Zou
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210824170457.710623-64-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=fw@strlen.de \
--cc=linux-kernel@vger.kernel.org \
--cc=pablo@netfilter.org \
--cc=sergey.marinkevich@eltex-co.ru \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).