linux-stable.git/net/core, branch linux-6.10.y

net: napi: Prevent overflow of napi_defer_hard_irqs

2024-10-10T10:00:22+00:00

[ Upstream commit 08062af0a52107a243f7608fd972edb54ca5b7f8 ]

In commit 6f8b12d661d0 ("net: napi: add hard irqs deferral feature")
napi_defer_irqs was added to net_device and napi_defer_irqs_count was
added to napi_struct, both as type int.

This value never goes below zero, so there is not reason for it to be a
signed int. Change the type for both from int to u32, and add an
overflow check to sysfs to limit the value to S32_MAX.

The limit of S32_MAX was chosen because the practical limit before this
patch was S32_MAX (anything larger was an overflow) and thus there are
no behavioral changes introduced. If the extra bit is needed in the
future, the limit can be raised.

Before this patch:

$ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs'
$ cat /sys/class/net/eth4/napi_defer_hard_irqs
-2147483647

After this patch:

$ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs'
bash: line 0: echo: write error: Numerical result out of range

Similarly, /sys/class/net/XXXXX/tx_queue_len is defined as unsigned:

include/linux/netdevice.h:      unsigned int            tx_queue_len;

And has an overflow check:

dev_change_tx_queue_len(..., unsigned long new_len):

  if (new_len != (unsigned int)new_len)
          return -ERANGE;

Suggested-by: Jakub Kicinski 
Signed-off-by: Joe Damato 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20240904153431.307932-1-jdamato@fastly.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netdev-genl: Set extack and fix error on napi-get

2024-10-10T10:00:21+00:00

[ Upstream commit 4e3a024b437ec0aee82550cc66a0f4e1a7a88a67 ]

In commit 27f91aaf49b3 ("netdev-genl: Add netlink framework functions
for napi"), when an invalid NAPI ID is specified the return value
-EINVAL is used and no extack is set.

Change the return value to -ENOENT and set the extack.

Before this commit:

$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
                          --do napi-get --json='{"id": 451}'
Netlink error: Invalid argument
nl_len = 36 (20) nl_flags = 0x100 nl_type = 2
	error: -22

After this commit:

$ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \
                         --do napi-get --json='{"id": 451}'
Netlink error: No such file or directory
nl_len = 44 (28) nl_flags = 0x300 nl_type = 2
	error: -2
	extack: {'bad-attr': '.id'}

Suggested-by: Jakub Kicinski 
Signed-off-by: Joe Damato 
Link: https://patch.msgid.link/20240831121707.17562-1-jdamato@fastly.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netpoll: Ensure clean state on setup failures

2024-10-10T10:00:19+00:00

[ Upstream commit ae5a0456e0b4cfd7e61619e55251ffdf1bc7adfb ]

Modify netpoll_setup() and __netpoll_setup() to ensure that the netpoll
structure (np) is left in a clean state if setup fails for any reason.
This prevents carrying over misconfigured fields in case of partial
setup success.

Key changes:
- np->dev is now set only after successful setup, ensuring it's always
  NULL if netpoll is not configured or if netpoll_setup() fails.
- np->local_ip is zeroed if netpoll setup doesn't complete successfully.
- Added DEBUG_NET_WARN_ON_ONCE() checks to catch unexpected states.
- Reordered some operations in __netpoll_setup() for better logical flow.

These changes improve the reliability of netpoll configuration, since it
assures that the structure is fully initialized or totally unset.

Suggested-by: Paolo Abeni 
Signed-off-by: Breno Leitao 
Link: https://patch.msgid.link/20240822111051.179850-2-leitao@debian.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: add more sanity checks to qdisc_pkt_len_init()

2024-10-10T10:00:08+00:00

[ Upstream commit ab9a9a9e9647392a19e7a885b08000e89c86b535 ]

One path takes care of SKB_GSO_DODGY, assuming
skb->len is bigger than hdr_len.

virtio_net_hdr_to_skb() does not fully dissect TCP headers,
it only make sure it is at least 20 bytes.

It is possible for an user to provide a malicious 'GSO' packet,
total length of 80 bytes.

- 20 bytes of IPv4 header
- 60 bytes TCP header
- a small gso_size like 8

virtio_net_hdr_to_skb() would declare this packet as a normal
GSO packet, because it would see 40 bytes of payload,
bigger than gso_size.

We need to make detect this case to not underflow
qdisc_skb_cb(skb)->pkt_len.

Fixes: 1def9238d4aa ("net_sched: more precise pkt_len computation")
Signed-off-by: Eric Dumazet 
Reviewed-by: Willem de Bruijn 
Reviewed-by: David Ahern 
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: avoid potential underflow in qdisc_pkt_len_init() with UFO

2024-10-10T10:00:08+00:00

[ Upstream commit c20029db28399ecc50e556964eaba75c43b1e2f1 ]

After commit 7c6d2ecbda83 ("net: be more gentle about silly gso
requests coming from user") virtio_net_hdr_to_skb() had sanity check
to detect malicious attempts from user space to cook a bad GSO packet.

Then commit cf9acc90c80ec ("net: virtio_net_hdr_to_skb: count
transport header in UFO") while fixing one issue, allowed user space
to cook a GSO packet with the following characteristic :

IPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28.

When this packet arrives in qdisc_pkt_len_init(), we end up
with hdr_len = 28 (IPv4 header + UDP header), matching skb->len

Then the following sets gso_segs to 0 :

gso_segs = DIV_ROUND_UP(skb->len - hdr_len,
                        shinfo->gso_size);

Then later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/

qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;

This leads to the following crash in fq_codel [1]

qdisc_pkt_len_init() is best effort, we only want an estimation
of the bytes sent on the wire, not crashing the kernel.

This patch is fixing this particular issue, a following one
adds more sanity checks for another potential bug.

[1]
[   70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000
[   70.724561] #PF: supervisor read access in kernel mode
[   70.724561] #PF: error_code(0x0000) - not-present page
[   70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0
[   70.724561] Oops: Oops: 0000 [#1] SMP NOPTI
[   70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991
[   70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel
[ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49
All code
========
   0:	24 08                	and    $0x8,%al
   2:	49 c1 e1 06          	shl    $0x6,%r9
   6:	44 89 7c 24 18       	mov    %r15d,0x18(%rsp)
   b:	45 31 ed             	xor    %r13d,%r13d
   e:	45 31 c0             	xor    %r8d,%r8d
  11:	31 ff                	xor    %edi,%edi
  13:	89 44 24 14          	mov    %eax,0x14(%rsp)
  17:	4c 03 8b 90 01 00 00 	add    0x190(%rbx),%r9
  1e:	eb 04                	jmp    0x24
  20:	39 ca                	cmp    %ecx,%edx
  22:	73 37                	jae    0x5b
  24:	4d 8b 39             	mov    (%r9),%r15
  27:	83 c7 01             	add    $0x1,%edi
  2a:*	49 8b 17             	mov    (%r15),%rdx		<-- trapping instruction
  2d:	49 89 11             	mov    %rdx,(%r9)
  30:	41 8b 57 28          	mov    0x28(%r15),%edx
  34:	45 8b 5f 34          	mov    0x34(%r15),%r11d
  38:	49 c7 07 00 00 00 00 	movq   $0x0,(%r15)
  3f:	49                   	rex.WB

Code starting with the faulting instruction
===========================================
   0:	49 8b 17             	mov    (%r15),%rdx
   3:	49 89 11             	mov    %rdx,(%r9)
   6:	41 8b 57 28          	mov    0x28(%r15),%edx
   a:	45 8b 5f 34          	mov    0x34(%r15),%r11d
   e:	49 c7 07 00 00 00 00 	movq   $0x0,(%r15)
  15:	49                   	rex.WB
[   70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202
[   70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000
[   70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
[   70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000
[   70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58
[   70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000
[   70.724561] FS:  000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000
[   70.724561] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   70.724561] CR2: 0000000000000000 CR3: 000000010c568000 CR4: 00000000000006f0
[   70.724561] Call Trace:
[   70.724561]  
[   70.724561] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434)
[   70.724561] ? page_fault_oops (arch/x86/mm/fault.c:715)
[   70.724561] ? exc_page_fault (./arch/x86/include/asm/irqflags.h:26 ./arch/x86/include/asm/irqflags.h:87 ./arch/x86/include/asm/irqflags.h:147 arch/x86/mm/fault.c:1489 arch/x86/mm/fault.c:1539)
[   70.724561] ? asm_exc_page_fault (./arch/x86/include/asm/idtentry.h:623)
[   70.724561] ? fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel
[   70.724561] dev_qdisc_enqueue (net/core/dev.c:3784)
[   70.724561] __dev_queue_xmit (net/core/dev.c:3880 (discriminator 2) net/core/dev.c:4390 (discriminator 2))
[   70.724561] ? irqentry_enter (kernel/entry/common.c:237)
[   70.724561] ? sysvec_apic_timer_interrupt (./arch/x86/include/asm/hardirq.h:74 (discriminator 2) arch/x86/kernel/apic/apic.c:1043 (discriminator 2) arch/x86/kernel/apic/apic.c:1043 (discriminator 2))
[   70.724561] ? trace_hardirqs_on (kernel/trace/trace_preemptirq.c:58 (discriminator 4))
[   70.724561] ? asm_sysvec_apic_timer_interrupt (./arch/x86/include/asm/idtentry.h:702)
[   70.724561] ? virtio_net_hdr_to_skb.constprop.0 (./include/linux/virtio_net.h:129 (discriminator 1))
[   70.724561] packet_sendmsg (net/packet/af_packet.c:3145 (discriminator 1) net/packet/af_packet.c:3177 (discriminator 1))
[   70.724561] ? _raw_spin_lock_bh (./arch/x86/include/asm/atomic.h:107 (discriminator 4) ./include/linux/atomic/atomic-arch-fallback.h:2170 (discriminator 4) ./include/linux/atomic/atomic-instrumented.h:1302 (discriminator 4) ./include/asm-generic/qspinlock.h:111 (discriminator 4) ./include/linux/spinlock.h:187 (discriminator 4) ./include/linux/spinlock_api_smp.h:127 (discriminator 4) kernel/locking/spinlock.c:178 (discriminator 4))
[   70.724561] ? netdev_name_node_lookup_rcu (net/core/dev.c:325 (discriminator 1))
[   70.724561] __sys_sendto (net/socket.c:730 (discriminator 1) net/socket.c:745 (discriminator 1) net/socket.c:2210 (discriminator 1))
[   70.724561] ? __sys_setsockopt (./include/linux/file.h:34 net/socket.c:2355)
[   70.724561] __x64_sys_sendto (net/socket.c:2222 (discriminator 1) net/socket.c:2218 (discriminator 1) net/socket.c:2218 (discriminator 1))
[   70.724561] do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1) arch/x86/entry/common.c:83 (discriminator 1))
[   70.724561] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
[   70.724561] RIP: 0033:0x41ae09

Fixes: cf9acc90c80ec ("net: virtio_net_hdr_to_skb: count transport header in UFO")
Reported-by: syzbot 
Signed-off-by: Eric Dumazet 
Cc: Jonathan Davies 
Reviewed-by: Willem de Bruijn 
Reviewed-by: Jonathan Davies 
Reviewed-by: David Ahern 
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: Fix gso_features_check to check for both dev->gso_{ipv4_,}max_size

2024-10-10T10:00:07+00:00

[ Upstream commit e609c959a939660c7519895f853dfa5624c6827a ]

Commit 24ab059d2ebd ("net: check dev->gso_max_size in gso_features_check()")
added a dev->gso_max_size test to gso_features_check() in order to fall
back to GSO when needed.

This was added as it was noticed that some drivers could misbehave if TSO
packets get too big. However, the check doesn't respect dev->gso_ipv4_max_size
limit. For instance, a device could be configured with BIG TCP for IPv4,
but not IPv6.

Therefore, add a netif_get_gso_max_size() equivalent to netif_get_gro_max_size()
and use the helper to respect both limits before falling back to GSO engine.

Fixes: 24ab059d2ebd ("net: check dev->gso_max_size in gso_features_check()")
Signed-off-by: Daniel Borkmann 
Cc: Eric Dumazet 
Cc: Paolo Abeni 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20240923212242.15669-2-daniel@iogearbox.net
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: Add netif_get_gro_max_size helper for GRO

2024-10-10T10:00:07+00:00

[ Upstream commit e8d4d34df715133c319fabcf63fdec684be75ff8 ]

Add a small netif_get_gro_max_size() helper which returns the maximum IPv4
or IPv6 GRO size of the netdevice.

We later add a netif_get_gso_max_size() equivalent as well for GSO, so that
these helpers can be used consistently instead of open-coded checks.

Signed-off-by: Daniel Borkmann 
Cc: Eric Dumazet 
Cc: Paolo Abeni 
Reviewed-by: Eric Dumazet 
Link: https://patch.msgid.link/20240923212242.15669-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni 
Stable-dep-of: e609c959a939 ("net: Fix gso_features_check to check for both dev->gso_{ipv4_,}max_size")
Signed-off-by: Sasha Levin

bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error

2024-10-04T14:32:59+00:00

[ Upstream commit 4b3786a6c5397dc220b1483d8e2f4867743e966f ]

For all non-tracing helpers which formerly had ARG_PTR_TO_{LONG,INT} as input
arguments, zero the value for the case of an error as otherwise it could leak
memory. For tracing, it is not needed given CAP_PERFMON can already read all
kernel memory anyway hence bpf_get_func_arg() and bpf_get_func_ret() is skipped
in here.

Also, the MTU helpers mtu_len pointer value is being written but also read.
Technically, the MEM_UNINIT should not be there in order to always force init.
Removing MEM_UNINIT needs more verifier rework though: MEM_UNINIT right now
implies two things actually: i) write into memory, ii) memory does not have
to be initialized. If we lift MEM_UNINIT, it then becomes: i) read into memory,
ii) memory must be initialized. This means that for bpf_*_check_mtu() we're
readding the issue we're trying to fix, that is, it would then be able to
write back into things like .rodata BPF maps. Follow-up work will rework the
MEM_UNINIT semantics such that the intent can be better expressed. For now
just clear the *mtu_len on error path which can be lifted later again.

Fixes: 8a67f2de9b1d ("bpf: expose bpf_strtol and bpf_strtoul to all program types")
Fixes: d7a4cb9b6705 ("bpf: Introduce bpf_strtol and bpf_strtoul helpers")
Signed-off-by: Daniel Borkmann 
Link: https://lore.kernel.org/bpf/e5edd241-59e7-5e39-0ee5-a51e31b6840a@iogearbox.net
Link: https://lore.kernel.org/r/20240913191754.13290-5-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: Fix helper writes to read-only maps

2024-10-04T14:32:59+00:00

[ Upstream commit 32556ce93bc45c730829083cb60f95a2728ea48b ]

Lonial found an issue that despite user- and BPF-side frozen BPF map
(like in case of .rodata), it was still possible to write into it from
a BPF program side through specific helpers having ARG_PTR_TO_{LONG,INT}
as arguments.

In check_func_arg() when the argument is as mentioned, the meta->raw_mode
is never set. Later, check_helper_mem_access(), under the case of
PTR_TO_MAP_VALUE as register base type, it assumes BPF_READ for the
subsequent call to check_map_access_type() and given the BPF map is
read-only it succeeds.

The helpers really need to be annotated as ARG_PTR_TO_{LONG,INT} | MEM_UNINIT
when results are written into them as opposed to read out of them. The
latter indicates that it's okay to pass a pointer to uninitialized memory
as the memory is written to anyway.

However, ARG_PTR_TO_{LONG,INT} is a special case of ARG_PTR_TO_FIXED_SIZE_MEM
just with additional alignment requirement. So it is better to just get
rid of the ARG_PTR_TO_{LONG,INT} special cases altogether and reuse the
fixed size memory types. For this, add MEM_ALIGNED to additionally ensure
alignment given these helpers write directly into the args via * = val.
The .arg*_size has been initialized reflecting the actual sizeof(*).

MEM_ALIGNED can only be used in combination with MEM_FIXED_SIZE annotated
argument types, since in !MEM_FIXED_SIZE cases the verifier does not know
the buffer size a priori and therefore cannot blindly write * = val.

Fixes: 57c3bb725a3d ("bpf: Introduce ARG_PTR_TO_{INT,LONG} arg types")
Reported-by: Lonial Con 
Signed-off-by: Daniel Borkmann 
Acked-by: Andrii Nakryiko 
Acked-by: Shung-Hsi Yu 
Link: https://lore.kernel.org/r/20240913191754.13290-3-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

bpf: Fail verification for sign-extension of packet data/data_end/data_meta

2024-10-04T14:32:51+00:00

[ Upstream commit 92de36080c93296ef9005690705cba260b9bd68a ]

syzbot reported a kernel crash due to
  commit 1f1e864b6555 ("bpf: Handle sign-extenstin ctx member accesses").
The reason is due to sign-extension of 32-bit load for
packet data/data_end/data_meta uapi field.

The original code looks like:
        r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */
        r3 = *(u32 *)(r1 + 80) /* load __sk_buff->data_end */
        r0 = r2
        r0 += 8
        if r3 > r0 goto +1
        ...
Note that __sk_buff->data load has 32-bit sign extension.

After verification and convert_ctx_accesses(), the final asm code looks like:
        r2 = *(u64 *)(r1 +208)
        r2 = (s32)r2
        r3 = *(u64 *)(r1 +80)
        r0 = r2
        r0 += 8
        if r3 > r0 goto pc+1
        ...
Note that 'r2 = (s32)r2' may make the kernel __sk_buff->data address invalid
which may cause runtime failure.

Currently, in C code, typically we have
        void *data = (void *)(long)skb->data;
        void *data_end = (void *)(long)skb->data_end;
        ...
and it will generate
        r2 = *(u64 *)(r1 +208)
        r3 = *(u64 *)(r1 +80)
        r0 = r2
        r0 += 8
        if r3 > r0 goto pc+1

If we allow sign-extension,
        void *data = (void *)(long)(int)skb->data;
        void *data_end = (void *)(long)skb->data_end;
        ...
the generated code looks like
        r2 = *(u64 *)(r1 +208)
        r2 <<= 32
        r2 s>>= 32
        r3 = *(u64 *)(r1 +80)
        r0 = r2
        r0 += 8
        if r3 > r0 goto pc+1
and this will cause verification failure since "r2 <<= 32" is not allowed
as "r2" is a packet pointer.

To fix this issue for case
  r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */
this patch added additional checking in is_valid_access() callback
function for packet data/data_end/data_meta access. If those accesses
are with sign-extenstion, the verification will fail.

  [1] https://lore.kernel.org/bpf/000000000000c90eee061d236d37@google.com/

Reported-by: syzbot+ad9ec60c8eaf69e6f99c@syzkaller.appspotmail.com
Fixes: 1f1e864b6555 ("bpf: Handle sign-extenstin ctx member accesses")
Acked-by: Eduard Zingerman 
Signed-off-by: Yonghong Song 
Link: https://lore.kernel.org/r/20240723153439.2429035-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Sasha Levin