The ebtables SNAT target keeps the Ethernet source address rewrite
behind skb_ensure_writable(skb, 0). This is intentional: at the bridge
ebtables hooks the Ethernet header is addressed through
skb_mac_header()/eth_hdr(), while skb->data points at the Ethernet
payload. Asking skb_ensure_writable() for ETH_HLEN bytes would check
the payload, not the Ethernet header, and would reintroduce the small
packet regression fixed by commit 63137bc588.
However, the optional ARP sender hardware address rewrite is different.
It writes through skb_store_bits() at an offset relative to skb->data:
skb_store_bits(skb, sizeof(struct arphdr), info->mac, ETH_ALEN)
skb_header_pointer() only safely reads the ARP header; it does not make
the later sender hardware address range writable. If that range is
still held in a nonlinear skb fragment backed by a splice-imported file
page, skb_store_bits() maps the frag page and copies the new MAC address
directly into it.
Ensure the ARP SHA range is writable before reading the ARP header and
before calling skb_store_bits().
Fixes: 63137bc588 ("netfilter: ebtables: Fixes dropping of small packets in bridge nat")
Reported-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Yiming Qian <yimingqian591@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Luxiao Xu says:
The function compat_mtw_from_user() converts ebtables extensions from
32-bit user structures to kernel native structures. However, it lacks
proper validation of the user-supplied match_size/target_size.
When certain extensions are processed, the kernel-side translation
logic may perform memory accesses based on the extension's expected
size. If the user provides a size smaller than what the extension
requires, it results in an out-of-bounds read as reported by KASAN.
This fix introduces a check to ensure match_size is at least as large
as the extension's required compatsize. This covers matches, watchers,
and targets, while maintaining compatibility with standard targets.
AFAIU this is relevant for matches that need to go though
match->compat_from_user() call. Those that use plain memcpy with the
user-provided size are ok because the caller checks that size vs the
start of the next rule entry offset (which itself is checked vs. total
size copied from userspace).
The ->compat_from_user() callbacks assume they can read compatsize bytes,
so they need this extra check.
Based on an earlier patch from Luxiao Xu.
Fixes: 81e675c227 ("netfilter: ebtables: add CONFIG_COMPAT support")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Luxiao Xu <rakukuip@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
sashiko reports for unrelated patch:
Does the core ebtables initialization in ebtables.c suffer from a similar race?
Once nf_register_sockopt() completes, the sockopts are exposed globally.
sockopt has to be registered last, just like in ip/ip6/arptables.
Fixes: 5b53951cfc ("netfilter: ebtables: use net_generic infra")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
sashiko reported for a related patch:
In modules like iptable_raw.c, [..], if register_pernet_subsys() fails,
the rollback might call kfree(rawtable_ops) before [..]
During this window, could a concurrent userspace process find the globally
visible template, trigger table_init(), [..]
The table init functions must always register the template last.
Otherwise, set/getsockopt can instantiate a table in a namespace
while the required pernet ops (contain the destructor) isn't available.
This change is also required in x_tables, handled in followup change.
Fixes: 87663c39f8 ("netfilter: ebtables: do not hook tables by default")
Reviewed-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Like previous patches for x_tables, follow same pattern in ebtables.
We can't reuse xt helpers: ebt_table struct layout is incompatible.
table->ops assignment is now done while still holding the ebt mutex
to make sure we never expose partially-filled table struct.
Fixes: 87663c39f8 ("netfilter: ebtables: do not hook tables by default")
Reviewed-by: Tristan Madani <tristan@talencesecurity.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Cross-merge networking fixes after downstream PR (net-7.0-rc2).
Conflicts:
tools/testing/selftests/drivers/net/hw/rss_ctx.py
19c3a2a81d ("selftests: drv-net: rss: Generate unique ports for RSS context tests")
ce5a0f4612 ("selftests: drv-net: rss_ctx: test RSS contexts persist after ifdown/up")
include/net/inet_connection_sock.h
858d2a4f67 ("tcp: fix potential race in tcp_v6_syn_recv_sock()")
fcd3d039fa ("tcp: make tcp_v{4,6}_send_check() static")
https://lore.kernel.org/aZ8PSFLzBrEU3I89@sirena.org.uk
drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
drivers/net/ethernet/mellanox/mlx5/core/en/xsk/pool.c
69050f8d6d ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types")
bf4afc53b7 ("Convert 'alloc_obj' family to use the new default GFP_KERNEL argument")
8a96b9144f ("net/mlx5e: Alloc xsk channel param out of mlx5e_open_xsk()")
Adjacent changes:
net/netfilter/ipvs/ip_vs_ctl.c
c59bd9e62e ("ipvs: use more counters to avoid service lookups")
bf4afc53b7 ("Convert 'alloc_obj' family to use the new default GFP_KERNEL argument")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This facility was disabled in commit
9e539c5b6d ("netfilter: nf_tables: disable expression reduction infra"),
because not all nft_exprs guarantee they will update the destination
register: some may set NFT_BREAK instead to cancel evaluation of the
rule.
This has been dead code ever since.
There are no plans to salvage this at this time, so remove this.
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20260224205048.4718-10-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
The next commits will transition away from using the hop-by-hop
extension header to encode packet length for BIG TCP. Add wrappers
around ip6->payload_len that return the actual value if it's non-zero,
and calculate it from skb->len if payload_len is set to zero (and a
symmetrical setter).
The new helpers are used wherever the surrounding code supports the
hop-by-hop jumbo header for BIG TCP IPv6, or the corresponding IPv4 code
uses skb_ip_totlen (e.g., in include/net/netfilter/nf_tables_ipv6.h).
No behavioral change in this commit.
Signed-off-by: Alice Mikityanska <alice@isovalent.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260205133925.526371-2-alice.kernel@fastmail.im
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The -EEXIST error code is reserved by the module loading infrastructure
to indicate that a module is already loaded. When a module's init
function returns -EEXIST, userspace tools like kmod interpret this as
"module already loaded" and treat the operation as successful, returning
0 to the user even though the module initialization actually failed.
Replace -EEXIST with -EBUSY to ensure correct error reporting in the module
initialization path.
Affected modules:
* ebtable_broute ebtable_filter ebtable_nat arptable_filter
* ip6table_filter ip6table_mangle ip6table_nat ip6table_raw
* ip6table_security iptable_filter iptable_mangle iptable_nat
* iptable_raw iptable_security
Signed-off-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Expose the input bridge interface ethernet address so it can be used to
redirect the packet to the receiving physical device for processing.
Tested with nft command line tool.
table bridge nat {
chain PREROUTING {
type filter hook prerouting priority 0; policy accept;
ether daddr de:ad:00:00:be:ef meta pkttype set host ether daddr set meta ibrhwdr accept
}
}
Joint work with Pablo Neira.
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Some Kconfig symbols were changed to depend on the 'bool' symbol
NETFILTER_XTABLES_LEGACY, which means they can now be set to built-in
when the xtables code itself is in a loadable module:
x86_64-linux-ld: vmlinux.o: in function `arpt_unregister_table_pre_exit':
(.text+0x1831987): undefined reference to `xt_find_table'
x86_64-linux-ld: vmlinux.o: in function `get_info.constprop.0':
arp_tables.c:(.text+0x1831aab): undefined reference to `xt_request_find_table_lock'
x86_64-linux-ld: arp_tables.c:(.text+0x1831bea): undefined reference to `xt_table_unlock'
x86_64-linux-ld: vmlinux.o: in function `do_arpt_get_ctl':
arp_tables.c:(.text+0x183205d): undefined reference to `xt_find_table_lock'
x86_64-linux-ld: arp_tables.c:(.text+0x18320c1): undefined reference to `xt_table_unlock'
x86_64-linux-ld: arp_tables.c:(.text+0x183219a): undefined reference to `xt_recseq'
Change these to depend on both NETFILTER_XTABLES and
NETFILTER_XTABLES_LEGACY.
Fixes: 9fce66583f ("netfilter: Exclude LEGACY TABLES on PREEMPT_RT.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Florian Westphal <fw@strlen.de>
Tested-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The seqcount xt_recseq is used to synchronize the replacement of
xt_table::private in xt_replace_table() against all readers such as
ipt_do_table()
To ensure that there is only one writer, the writing side disables
bottom halves. The sequence counter can be acquired recursively. Only the
first invocation modifies the sequence counter (signaling that a writer
is in progress) while the following (recursive) writer does not modify
the counter.
The lack of a proper locking mechanism for the sequence counter can lead
to live lock on PREEMPT_RT if the high prior reader preempts the
writer. Additionally if the per-CPU lock on PREEMPT_RT is removed from
local_bh_disable() then there is no synchronisation for the per-CPU
sequence counter.
The affected code is "just" the legacy netfilter code which is replaced
by "netfilter tables". That code can be disabled without sacrificing
functionality because everything is provided by the newer
implementation. This will only requires the usage of the "-nft" tools
instead of the "-legacy" ones.
The long term plan is to remove the legacy code so lets accelerate the
progress.
Relax dependencies on iptables legacy, replace select with depends on,
this should cause no harm to existing kernel configs and users can still
toggle IP{6}_NF_IPTABLES_LEGACY in any case.
Make EBTABLES_LEGACY, IPTABLES_LEGACY and ARPTABLES depend on
NETFILTER_XTABLES_LEGACY. Hide xt_recseq and its users,
xt_register_table() and xt_percpu_counter_alloc() behind
NETFILTER_XTABLES_LEGACY. Let NETFILTER_XTABLES_LEGACY depend on
!PREEMPT_RT.
This will break selftest expecing the legacy options enabled and will be
addressed in a following patch.
Co-developed-by: Florian Westphal <fw@strlen.de>
Co-developed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The config NF_CONNTRACK_BRIDGE will change the bridge forwarding for
fragmented packets.
The original bridge does not know that it is a fragmented packet and
forwards it directly, after NF_CONNTRACK_BRIDGE is enabled, function
nf_br_ip_fragment and br_ip6_fragment will check the headroom.
In original br_forward, insufficient headroom of skb may indeed exist,
but there's still a way to save the skb in the device driver after
dev_queue_xmit.So droping the skb will change the original bridge
forwarding in some cases.
Fixes: 3c171f496e ("netfilter: bridge: add connection tracking system")
Signed-off-by: Huajian Yang <huajianyang@asrmicro.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
strncpy() is deprecated for use on NUL-terminated destination strings [1] and
as such we should prefer more robust and less ambiguous string interfaces.
In this particular instance, the usage of strncpy() is fine and works as
expected. However, towards the goal of [2], we should consider replacing
it with an alternative as many instances of strncpy() are bug-prone. Its
removal from the kernel promotes better long term health for the
codebase.
The current usage of strncpy() likely just wants the NUL-padding
behavior offered by strncpy() and doesn't care about the
NUL-termination. Since the compiler doesn't know the size of @dest, we
can't use strtomem_pad(). Instead, use strscpy_pad() which behaves
functionally the same as strncpy() in this context -- as we expect
br_dev->name to be NUL-terminated itself.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90 [2]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This option makes legacy Netfilter Kconfig user selectable, giving users
the option to configure iptables without enabling any other config.
Make the following KConfig entries user selectable:
* BRIDGE_NF_EBTABLES_LEGACY
* IP_NF_ARPTABLES
* IP_NF_IPTABLES_LEGACY
* IP6_NF_IPTABLES_LEGACY
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
When we are allocating an array, using kmemdup_array() to take care about
multiplication and possible overflows.
Also it makes auditing the code easier.
Signed-off-by: Yan Zhen <yanzhen@vivo.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
mono_delivery_time was added to check if skb->tstamp has delivery
time in mono clock base (i.e. EDT) otherwise skb->tstamp has
timestamp in ingress and delivery_time at egress.
Renaming the bitfield from mono_delivery_time to tstamp_type is for
extensibilty for other timestamps such as userspace timestamp
(i.e. SO_TXTIME) set via sock opts.
As we are renaming the mono_delivery_time to tstamp_type, it makes
sense to start assigning tstamp_type based on enum defined
in this commit.
Earlier we used bool arg flag to check if the tstamp is mono in
function skb_set_delivery_time, Now the signature of the functions
accepts tstamp_type to distinguish between mono and real time.
Also skb_set_delivery_type_by_clockid is a new function which accepts
clockid to determine the tstamp_type.
In future tstamp_type:1 can be extended to support userspace timestamp
by increasing the bitfield.
Signed-off-by: Abhishek Chauhan <quic_abchauha@quicinc.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509211834.3235191-2-quic_abchauha@quicinc.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
