[ Upstream commit 0b05b0cd78 ]
Split __sys_getsockopt() into two functions by removing the core
logic into a sub-function (do_sock_getsockopt()). This will avoid
code duplication when doing the same operation in other callers, for
instance.
do_sock_getsockopt() will be called by io_uring getsockopt() command
operation in the following patch.
The same was done for the setsockopt pair.
Suggested-by: Martin KaFai Lau <martin.lau@linux.dev>
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20231016134750.1381153-5-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: 33f339a1ba ("bpf, net: Fix a potential race in do_sock_getsockopt()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit c2deb2e971 ]
sk->sk_rcvbuf in __sock_queue_rcv_skb() and __sk_receive_skb() can be
changed by other threads. Mark this as benign using READ_ONCE().
This patch is aimed at reducing the number of benign races reported by
KCSAN in order to focus future debugging effort on harmful races.
Signed-off-by: linke li <lilinke99@qq.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 12a686c2e7 ]
This patch adds /proc/sys/net/core/mem_pcpu_rsv sysctl file,
to make SK_MEMORY_PCPU_RESERV tunable.
Commit 3cd3399dd7 ("net: implement per-cpu reserves for
memory_allocated") introduced per-cpu forward alloc cache:
"Implement a per-cpu cache of +1/-1 MB, to reduce number
of changes to sk->sk_prot->memory_allocated, which
would otherwise be cause of false sharing."
sk_prot->memory_allocated points to global atomic variable:
atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp;
If increasing the per-cpu cache size from 1MB to e.g. 16MB,
changes to sk->sk_prot->memory_allocated can be further reduced.
Performance may be improved on system with many cores.
Signed-off-by: Adam Li <adamli@os.amperecomputing.com>
Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 3584718cf2 ("net: fix sk_memory_allocated_{add|sub} vs softirqs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a54d51fb2d ]
Generic sk_busy_loop_end() only looks at sk->sk_receive_queue
for presence of packets.
Problem is that for UDP sockets after blamed commit, some packets
could be present in another queue: udp_sk(sk)->reader_queue
In some cases, a busy poller could spin until timeout expiration,
even if some packets are available in udp_sk(sk)->reader_queue.
v3: - make sk_busy_loop_end() nicer (Willem)
v2: - add a READ_ONCE(sk->sk_family) in sk_is_inet() to avoid KCSAN splats.
- add a sk_is_inet() check in sk_is_udp() (Willem feedback)
- add a sk_is_inet() check in sk_is_tcp().
Fixes: 2276f58ac5 ("udp: use a separate rx queue for packet reception")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit eb44ad4e63 ]
This field can be read or written without socket lock being held.
Add annotations to avoid load-store tearing.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
As with sk->sk_shutdown shown in the previous patch, sk->sk_err can be
read locklessly by unix_dgram_sendmsg().
Let's use READ_ONCE() for sk_err as well.
Note that the writer side is marked by commit cc04410af7 ("af_unix:
annotate lockless accesses to sk->sk_err").
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk->sk_bind_phc is read locklessly. Add corresponding annotations.
Fixes: d463126e23 ("net: sock: extend SO_TIMESTAMPING for PHC binding")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk->sk_tsflags can be read locklessly, add corresponding annotations.
Fixes: b9f40e21ef ("net-timestamp: move timestamp flags out of sk_flags")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Every time sk->sk_forward_alloc is read locklessly,
add a READ_ONCE().
Add sk_forward_alloc_add() helper to centralize updates,
to reduce number of WRITE_ONCE().
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
inet_sk_diag_fill() has been changed to use sk_forward_alloc_get(),
but sk_get_meminfo() was forgotten.
Fixes: 292e6077b0 ("net: introduce sk_forward_alloc_get()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs locklessly. This means sk->sk_lingertime
can be read while other threads are changing its value.
Other reads also happen without socket lock being held,
and must be annotated.
Remove preprocessor logic using BITS_PER_LONG, compilers
are smart enough to figure this by themselves.
v2: fixed a clang W=1 (-Wtautological-constant-out-of-range-compare) warning
(Jakub)
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The status of global socket memory pressure is updated when:
a) __sk_mem_raise_allocated():
enter: sk_memory_allocated(sk) > sysctl_mem[1]
leave: sk_memory_allocated(sk) <= sysctl_mem[0]
b) __sk_mem_reduce_allocated():
leave: sk_under_memory_pressure(sk) &&
sk_memory_allocated(sk) < sysctl_mem[0]
So the conditions of leaving global pressure are inconstant, which
may lead to the situation that one pressured net-memcg prevents the
global pressure from being cleared when there is indeed no global
pressure, thus the global constrains are still in effect unexpectedly
on the other sockets.
This patch fixes this by ignoring the net-memcg's pressure when
deciding whether should leave global memory pressure.
Fixes: e1aab161e0 ("socket: initial cgroup code.")
Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Link: https://lore.kernel.org/r/20230816091226.1542-1-wuyun.abel@bytedance.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
IP_MULTICAST_LOOP socket option can now be set/read
without locking the socket.
v3: fix build bot error reported in ipvs set_mcast_loop()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
IPV6_ADDRFORM socket option is evil, because it can change sock->ops
while other threads might read it. Same issue for sk->sk_family
being set to AF_INET.
Adding READ_ONCE() over sock->ops reads is needed for sockets
that might be impacted by IPV6_ADDRFORM.
Note that mptcp_is_tcpsk() can also overwrite sock->ops.
Adding annotations for all sk->sk_family reads will require
more patches :/
BUG: KCSAN: data-race in ____sys_sendmsg / do_ipv6_setsockopt
write to 0xffff888109f24ca0 of 8 bytes by task 4470 on cpu 0:
do_ipv6_setsockopt+0x2c5e/0x2ce0 net/ipv6/ipv6_sockglue.c:491
ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012
udpv6_setsockopt+0x95/0xa0 net/ipv6/udp.c:1690
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3663
__sys_setsockopt+0x1c3/0x230 net/socket.c:2273
__do_sys_setsockopt net/socket.c:2284 [inline]
__se_sys_setsockopt net/socket.c:2281 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2281
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read to 0xffff888109f24ca0 of 8 bytes by task 4469 on cpu 1:
sock_sendmsg_nosec net/socket.c:724 [inline]
sock_sendmsg net/socket.c:747 [inline]
____sys_sendmsg+0x349/0x4c0 net/socket.c:2503
___sys_sendmsg net/socket.c:2557 [inline]
__sys_sendmmsg+0x263/0x500 net/socket.c:2643
__do_sys_sendmmsg net/socket.c:2672 [inline]
__se_sys_sendmmsg net/socket.c:2669 [inline]
__x64_sys_sendmmsg+0x57/0x60 net/socket.c:2669
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0xffffffff850e32b8 -> 0xffffffff850da890
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 4469 Comm: syz-executor.1 Not tainted 6.4.0-rc5-syzkaller-00313-g4c605260bc60 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230808135809.2300241-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Change the new (unreleased) SO_PEERPIDFD sockopt to return ENODATA
rather than ESRCH if a socket type does not support remote peer-PID
queries.
Currently, SO_PEERPIDFD returns ESRCH when the socket in question is
not an AF_UNIX socket. This is quite unexpected, given that one would
assume ESRCH means the peer process already exited and thus cannot be
found. However, in that case the sockopt actually returns EINVAL (via
pidfd_prepare()). This is rather inconsistent with other syscalls, which
usually return ESRCH if a given PID refers to a non-existant process.
This changes SO_PEERPIDFD to return ENODATA instead. This is also what
SO_PEERGROUPS returns, and thus keeps a consistent behavior across
sockopts.
Note that this code is returned in 2 cases: First, if the socket type is
not AF_UNIX, and secondly if the socket was not yet connected. In both
cases ENODATA seems suitable.
Signed-off-by: David Rheinsberg <david@readahead.eu>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Luca Boccassi <bluca@debian.org>
Fixes: 7b26952a91 ("net: core: add getsockopt SO_PEERPIDFD")
Link: https://lore.kernel.org/r/20230807081225.816199-1-david@readahead.eu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit df8fc4e934 ("kbuild: Enable -fstrict-flex-arrays=3") started
applying strict rules to standard string functions.
It does not work well with conventional socket code around each protocol-
specific sockaddr_XXX struct, which is cast from sockaddr_storage and has
a bigger size than fortified functions expect. See these commits:
commit 06d4c8a808 ("af_unix: Fix fortify_panic() in unix_bind_bsd().")
commit ecb4534b6a ("af_unix: Terminate sun_path when bind()ing pathname socket.")
commit a0ade8404c ("af_packet: Fix warning of fortified memcpy() in packet_getname().")
We must cast the protocol-specific address back to sockaddr_storage
to call such functions.
However, in the case of getsockaddr(SO_PEERNAME), the rationale is a bit
unclear as the buffer is defined by char[128] which is the same size as
sockaddr_storage.
Let's use sockaddr_storage explicitly.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs locklessly. This means sk->sk_priority
can be read while other threads are changing its value.
Other reads also happen without socket lock being held.
Add missing annotations where needed.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In a prior commit I forgot that sk_getsockopt() reads
sk->sk_ll_usec without holding a lock.
Fixes: 0dbffbb533 ("net: annotate data race around sk_ll_usec")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs locklessly, thus we need to annotate the read
of sk->sk_peek_off.
While we are at it, add corresponding annotations to sk_set_peek_off()
and unix_set_peek_off().
Fixes: b9bb53f383 ("sock: convert sk_peek_offset functions to WRITE_ONCE")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk->sk_mark is often read while another thread could change the value.
Fixes: 4a19ec5800 ("[NET]: Introducing socket mark socket option.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In a prior commit, I forgot to change sk_getsockopt()
when reading sk->sk_rcvbuf locklessly.
Fixes: ebb3b78db7 ("tcp: annotate sk->sk_rcvbuf lockless reads")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In a prior commit, I forgot to change sk_getsockopt()
when reading sk->sk_sndbuf locklessly.
Fixes: e292f05e0d ("tcp: annotate sk->sk_sndbuf lockless reads")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs without locks, we must add annotations
to sk->sk_rcvtimeo and sk->sk_sndtimeo.
In the future we might allow fetching these fields before
we lock the socket in TCP fast path.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In a prior commit, I forgot to change sk_getsockopt()
when reading sk->sk_rcvlowat locklessly.
Fixes: eac66402d1 ("net: annotate sk->sk_rcvlowat lockless reads")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs locklessly. This means sk->sk_max_pacing_rate
can be read while other threads are changing its value.
Fixes: 62748f32d5 ("net: introduce SO_MAX_PACING_RATE")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs locklessly. This means sk->sk_txrehash
can be read while other threads are changing its value.
Other locations were handled in commit cb6cd2cec7
("tcp: Change SYN ACK retransmit behaviour to account for rehash")
Fixes: 26859240e4 ("txhash: Add socket option to control TX hash rethink behavior")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Akhmat Karakotov <hmukos@yandex-team.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
sk_getsockopt() runs locklessly. This means sk->sk_reserved_mem
can be read while other threads are changing its value.
Add missing annotations where they are needed.
Fixes: 2bb2f5fb21 ("net: add new socket option SO_RESERVE_MEM")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 1f86123b97 ("net: align SO_RCVMARK required
privileges with SO_MARK") because the reasoning in the commit message
is not really correct:
SO_RCVMARK is used for 'reading' incoming skb mark (via cmsg), as such
it is more equivalent to 'getsockopt(SO_MARK)' which has no priv check
and retrieves the socket mark, rather than 'setsockopt(SO_MARK) which
sets the socket mark and does require privs.
Additionally incoming skb->mark may already be visible if
sysctl_fwmark_reflect and/or sysctl_tcp_fwmark_accept are enabled.
Furthermore, it is easier to block the getsockopt via bpf
(either cgroup setsockopt hook, or via syscall filters)
then to unblock it if it requires CAP_NET_RAW/ADMIN.
On Android the socket mark is (among other things) used to store
the network identifier a socket is bound to. Setting it is privileged,
but retrieving it is not. We'd like unprivileged userspace to be able
to read the network id of incoming packets (where mark is set via
iptables [to be moved to bpf])...
An alternative would be to add another sysctl to control whether
setting SO_RCVMARK is privilged or not.
(or even a MASK of which bits in the mark can be exposed)
But this seems like over-engineering...
Note: This is a non-trivial revert, due to later merged commit e42c7beee7
("bpf: net: Consider has_current_bpf_ctx() when testing capable() in sk_setsockopt()")
which changed both 'ns_capable' into 'sockopt_ns_capable' calls.
Fixes: 1f86123b97 ("net: align SO_RCVMARK required privileges with SO_MARK")
Cc: Larysa Zaremba <larysa.zaremba@intel.com>
Cc: Simon Horman <simon.horman@corigine.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Eyal Birger <eyal.birger@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Patrick Rohr <prohr@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230618103130.51628-1-maze@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Blamed commit added these helpers for sake of detecting RAW
sockets specific ioctl.
syzbot complained about it [1].
Issue here is that RAW sockets could pretend there was no need
to call ipmr_sk_ioctl()
Regardless of inet_sk(sk)->inet_num, we must be prepared
for ipmr_ioctl() being called later. This must happen
from ipmr_sk_ioctl() context only.
We could add a safety check in ipmr_ioctl() at the risk of breaking
applications.
Instead, remove sk_is_ipmr() and sk_is_icmpv6() because their
name would be misleading, once we change their implementation.
[1]
BUG: KASAN: stack-out-of-bounds in ipmr_ioctl+0xb12/0xbd0 net/ipv4/ipmr.c:1654
Read of size 4 at addr ffffc90003aefae4 by task syz-executor105/5004
CPU: 0 PID: 5004 Comm: syz-executor105 Not tainted 6.4.0-rc6-syzkaller-01304-gc08afcdcf952 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
ipmr_ioctl+0xb12/0xbd0 net/ipv4/ipmr.c:1654
raw_ioctl+0x4e/0x1e0 net/ipv4/raw.c:881
sock_ioctl_out net/core/sock.c:4186 [inline]
sk_ioctl+0x151/0x440 net/core/sock.c:4214
inet_ioctl+0x18c/0x380 net/ipv4/af_inet.c:1001
sock_do_ioctl+0xcc/0x230 net/socket.c:1189
sock_ioctl+0x1f8/0x680 net/socket.c:1306
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x197/0x210 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2944bf6ad9
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 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 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd8897a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2944bf6ad9
RDX: 0000000000000000 RSI: 00000000000089e1 RDI: 0000000000000003
RBP: 00007f2944bbac80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2944bbad10
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
The buggy address belongs to stack of task syz-executor105/5004
and is located at offset 36 in frame:
sk_ioctl+0x0/0x440 net/core/sock.c:4172
This frame has 2 objects:
[32, 36) 'karg'
[48, 88) 'buffer'
Fixes: e1d001fa5b ("net: ioctl: Use kernel memory on protocol ioctl callbacks")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230619124336.651528-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl callback. This is not flexible, because it is hard to reuse these
functions without passing userspace buffers.
Change the "struct proto" ioctls to avoid touching userspace memory and
operate on kernel buffers, i.e., all protocol's ioctl callbacks is
adapted to operate on a kernel memory other than on userspace (so, no
more {put,get}_user() and friends being called in the ioctl callback).
This changes the "struct proto" ioctl format in the following way:
int (*ioctl)(struct sock *sk, int cmd,
- unsigned long arg);
+ int *karg);
(Important to say that this patch does not touch the "struct proto_ops"
protocols)
So, the "karg" argument, which is passed to the ioctl callback, is a
pointer allocated to kernel space memory (inside a function wrapper).
This buffer (karg) may contain input argument (copied from userspace in
a prep function) and it might return a value/buffer, which is copied
back to userspace if necessary. There is not one-size-fits-all format
(that is I am using 'may' above), but basically, there are three type of
ioctls:
1) Do not read from userspace, returns a result to userspace
2) Read an input parameter from userspace, and does not return anything
to userspace
3) Read an input from userspace, and return a buffer to userspace.
The default case (1) (where no input parameter is given, and an "int" is
returned to userspace) encompasses more than 90% of the cases, but there
are two other exceptions. Here is a list of exceptions:
* Protocol RAW:
* cmd = SIOCGETVIFCNT:
* input and output = struct sioc_vif_req
* cmd = SIOCGETSGCNT
* input and output = struct sioc_sg_req
* Explanation: for the SIOCGETVIFCNT case, userspace passes the input
argument, which is struct sioc_vif_req. Then the callback populates
the struct, which is copied back to userspace.
* Protocol RAW6:
* cmd = SIOCGETMIFCNT_IN6
* input and output = struct sioc_mif_req6
* cmd = SIOCGETSGCNT_IN6
* input and output = struct sioc_sg_req6
* Protocol PHONET:
* cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
* input int (4 bytes)
* Nothing is copied back to userspace.
For the exception cases, functions sock_sk_ioctl_inout() will
copy the userspace input, and copy it back to kernel space.
The wrapper that prepare the buffer and put the buffer back to user is
sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
calls sk_ioctl(), which will handle all cases.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230609152800.830401-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Syzkaller got the following report:
BUG: KASAN: use-after-free in sk_setup_caps+0x621/0x690 net/core/sock.c:2018
Read of size 8 at addr ffff888027f82780 by task syz-executor276/3255
The function sk_setup_caps (called by ip6_sk_dst_store_flow->
ip6_dst_store) referenced already freed memory as this memory was
freed by parallel task in udpv6_sendmsg->ip6_sk_dst_lookup_flow->
sk_dst_check.
task1 (connect) task2 (udp6_sendmsg)
sk_setup_caps->sk_dst_set |
| sk_dst_check->
| sk_dst_set
| dst_release
sk_setup_caps references |
to already freed dst_entry|
The reason for this race condition is: sk_setup_caps() keeps using
the dst after transferring the ownership to the dst cache.
Found by Linux Verification Center (linuxtesting.org) with syzkaller.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Vladislav Efanov <VEfanov@ispras.ru>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
