tools/lib/bpf/ringbuf.c
927cbb478adf ("libbpf: Handle size overflow for ringbuf mmap")
b486d19a0ab0 ("libbpf: checkpatch: Fixed code alignments in ringbuf.c")
https://lore.kernel.org/all/20221121122707.44d1446a@canb.auug.org.au/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When holding a reader-writer spin lock we cannot sleep. Calling
setup_udp_tunnel_sock() with write lock held violates this rule, because we
end up calling percpu_down_read(), which might sleep, as syzbot reports
[1]:
__might_resched.cold+0x222/0x26b kernel/sched/core.c:9890
percpu_down_read include/linux/percpu-rwsem.h:49 [inline]
cpus_read_lock+0x1b/0x140 kernel/cpu.c:310
static_key_slow_inc+0x12/0x20 kernel/jump_label.c:158
udp_tunnel_encap_enable include/net/udp_tunnel.h:187 [inline]
setup_udp_tunnel_sock+0x43d/0x550 net/ipv4/udp_tunnel_core.c:81
l2tp_tunnel_register+0xc51/0x1210 net/l2tp/l2tp_core.c:1509
pppol2tp_connect+0xcdc/0x1a10 net/l2tp/l2tp_ppp.c:723
Trim the writer-side critical section for sk_callback_lock down to the
minimum, so that it covers only operations on sk_user_data.
Also, when grabbing the sk_callback_lock, we always need to disable BH, as
Eric points out. Failing to do so leads to deadlocks because we acquire
sk_callback_lock in softirq context, which can get stuck waiting on us if:
1) it runs on the same CPU, or
CPU0
----
lock(clock-AF_INET6);
<Interrupt>
lock(clock-AF_INET6);
2) lock ordering leads to priority inversion
CPU0 CPU1
---- ----
lock(clock-AF_INET6);
local_irq_disable();
lock(&tcp_hashinfo.bhash[i].lock);
lock(clock-AF_INET6);
<Interrupt>
lock(&tcp_hashinfo.bhash[i].lock);
... as syzbot reports [2,3]. Use the _bh variants for write_(un)lock.
[1] https://lore.kernel.org/netdev/0000000000004e78ec05eda79749@google.com/
[2] https://lore.kernel.org/netdev/000000000000e38b6605eda76f98@google.com/
[3] https://lore.kernel.org/netdev/000000000000dfa31e05eda76f75@google.com/
v2:
- Check and set sk_user_data while holding sk_callback_lock for both
L2TP encapsulation types (IP and UDP) (Tetsuo)
Cc: Tom Parkin <tparkin@katalix.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Fixes: b68777d54fac ("l2tp: Serialize access to sk_user_data with sk_callback_lock")
Reported-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+703d9e154b3b58277261@syzkaller.appspotmail.com
Reported-by: syzbot+50680ced9e98a61f7698@syzkaller.appspotmail.com
Reported-by: syzbot+de987172bb74a381879b@syzkaller.appspotmail.com
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/linux/bpf.h
1f6e04a1c7b8 ("bpf: Fix offset calculation error in __copy_map_value and zero_map_value")
aa3496accc41 ("bpf: Refactor kptr_off_tab into btf_record")
f71b2f64177a ("bpf: Refactor map->off_arr handling")
https://lore.kernel.org/all/20221114095000.67a73239@canb.auug.org.au/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sk->sk_user_data has multiple users, which are not compatible with each
other. Writers must synchronize by grabbing the sk->sk_callback_lock.
l2tp currently fails to grab the lock when modifying the underlying tunnel
socket fields. Fix it by adding appropriate locking.
We err on the side of safety and grab the sk_callback_lock also inside the
sk_destruct callback overridden by l2tp, even though there should be no
refs allowing access to the sock at the time when sk_destruct gets called.
v4:
- serialize write to sk_user_data in l2tp sk_destruct
v3:
- switch from sock lock to sk_callback_lock
- document write-protection for sk_user_data
v2:
- update Fixes to point to origin of the bug
- use real names in Reported/Tested-by tags
Cc: Tom Parkin <tparkin@katalix.com>
Fixes: 3557baabf280 ("[L2TP]: PPP over L2TP driver core")
Reported-by: Haowei Yan <g1042620637@gmail.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit d38afeec26ed ("tcp/udp: Call inet6_destroy_sock()
in IPv6 sk->sk_destruct()."), we call inet6_destroy_sock() in
sk->sk_destruct() by setting inet6_sock_destruct() to it to make
sure we do not leak inet6-specific resources.
Now we can remove unnecessary inet6_destroy_sock() calls in
sk->sk_prot->destroy().
DCCP and SCTP have their own sk->sk_destruct() function, so we
change them separately in the following patches.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
We had historically not checked that genlmsghdr.reserved is 0 on input which prevents us from using those precious bytes in the future. One use case would be to extend the cmd field, which is currently just 8 bits wide and 256 is not a lot of commands for some core families. To make sure that new families do the right thing by default put the onus of opting out of validation on existing families. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel) Signed-off-by: David S. Miller <davem@davemloft.net>
Follow the advice of the below link and prefer 'strscpy' in this subsystem. Conversion is 1:1 because the return value is not used. Generated by a coccinelle script. Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/ Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Link: https://lore.kernel.org/r/20220818210222.8515-1-wsa+renesas@sang-engineering.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When building with Clang we encounter the following warnings: | net/l2tp/l2tp_debugfs.c:187:40: error: format specifies type 'unsigned | short' but the argument has type 'u32' (aka 'unsigned int') | [-Werror,-Wformat] seq_printf(m, " nr %hu, ns %hu\n", session->nr, | session->ns); - | net/l2tp/l2tp_debugfs.c:196:32: error: format specifies type 'unsigned | short' but the argument has type 'int' [-Werror,-Wformat] | session->l2specific_type, l2tp_get_l2specific_len(session)); - | net/l2tp/l2tp_debugfs.c:219:6: error: format specifies type 'unsigned | short' but the argument has type 'u32' (aka 'unsigned int') | [-Werror,-Wformat] session->nr, session->ns, Both session->nr and ->nc are of type `u32`. The currently used format specifier is `%hu` which describes a `u16`. My proposed fix is to listen to Clang and use the correct format specifier `%u`. For the warning at line 196, l2tp_get_l2specific_len() returns an int and should therefore be using the `%d` format specifier. Link: https://github.com/ClangBuiltLinux/linux/issues/378 Signed-off-by: Justin Stitt <justinstitt@google.com> Acked-by: Guillaume Nault <gnault@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
When building with clang we encounter this warning: | net/l2tp/l2tp_ppp.c:1557:6: error: format specifies type 'unsigned | short' but the argument has type 'u32' (aka 'unsigned int') | [-Werror,-Wformat] session->nr, session->ns, Both session->nr and session->ns are of type u32. The format specifier previously used is `%hu` which would truncate our unsigned integer from 32 to 16 bits. This doesn't seem like intended behavior, if it is then perhaps we need to consider suppressing the warning with pragma clauses. This patch should get us closer to the goal of enabling the -Wformat flag for Clang builds. Link: https://github.com/ClangBuiltLinux/linux/issues/378 Signed-off-by: Justin Stitt <justinstitt@google.com> Acked-by: Guillaume Nault <gnault@redhat.com> Link: https://lore.kernel.org/r/20220706230833.535238-1-justinstitt@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When len >= INT_MAX - transhdrlen, ulen = len + transhdrlen will be overflow. To fix, we can follow what udpv6 does and subtract the transhdrlen from the max. Signed-off-by: Wang Yufen <wangyufen@huawei.com> Link: https://lore.kernel.org/r/20220607120028.845916-2-wangyufen@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>