| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| A malicious actor with access to the network could exploit a Path Traversal vulnerability found in the UniFi Network Application to access files on the underlying system that could be manipulated to access an underlying account. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: iscsi: Fix conn use after free during resets
If we haven't done a unbind target call we can race where
iscsi_conn_teardown wakes up the EH thread and then frees the conn while
those threads are still accessing the conn ehwait.
We can only do one TMF per session so this just moves the TMF fields from
the conn to the session. We can then rely on the
iscsi_session_teardown->iscsi_remove_session->__iscsi_unbind_session call
to remove the target and it's devices, and know after that point there is
no device or scsi-ml callout trying to access the session. |
| In the Linux kernel, the following vulnerability has been resolved:
powerpc/bpf: Fix detecting BPF atomic instructions
Commit 91c960b0056672 ("bpf: Rename BPF_XADD and prepare to encode other
atomics in .imm") converted BPF_XADD to BPF_ATOMIC and added a way to
distinguish instructions based on the immediate field. Existing JIT
implementations were updated to check for the immediate field and to
reject programs utilizing anything more than BPF_ADD (such as BPF_FETCH)
in the immediate field.
However, the check added to powerpc64 JIT did not look at the correct
BPF instruction. Due to this, such programs would be accepted and
incorrectly JIT'ed resulting in soft lockups, as seen with the atomic
bounds test. Fix this by looking at the correct immediate value. |
| In the Linux kernel, the following vulnerability has been resolved:
nfsd: fix NULL dereference in nfs3svc_encode_getaclres
In error cases the dentry may be NULL.
Before 20798dfe249a, the encoder also checked dentry and
d_really_is_positive(dentry), but that looks like overkill to me--zero
status should be enough to guarantee a positive dentry.
This isn't the first time we've seen an error-case NULL dereference
hidden in the initialization of a local variable in an xdr encoder. But
I went back through the other recent rewrites and didn't spot any
similar bugs. |
| In the Linux kernel, the following vulnerability has been resolved:
net: validate lwtstate->data before returning from skb_tunnel_info()
skb_tunnel_info() returns pointer of lwtstate->data as ip_tunnel_info
type without validation. lwtstate->data can have various types such as
mpls_iptunnel_encap, etc and these are not compatible.
So skb_tunnel_info() should validate before returning that pointer.
Splat looks like:
BUG: KASAN: slab-out-of-bounds in vxlan_get_route+0x418/0x4b0 [vxlan]
Read of size 2 at addr ffff888106ec2698 by task ping/811
CPU: 1 PID: 811 Comm: ping Not tainted 5.13.0+ #1195
Call Trace:
dump_stack_lvl+0x56/0x7b
print_address_description.constprop.8.cold.13+0x13/0x2ee
? vxlan_get_route+0x418/0x4b0 [vxlan]
? vxlan_get_route+0x418/0x4b0 [vxlan]
kasan_report.cold.14+0x83/0xdf
? vxlan_get_route+0x418/0x4b0 [vxlan]
vxlan_get_route+0x418/0x4b0 [vxlan]
[ ... ]
vxlan_xmit_one+0x148b/0x32b0 [vxlan]
[ ... ]
vxlan_xmit+0x25c5/0x4780 [vxlan]
[ ... ]
dev_hard_start_xmit+0x1ae/0x6e0
__dev_queue_xmit+0x1f39/0x31a0
[ ... ]
neigh_xmit+0x2f9/0x940
mpls_xmit+0x911/0x1600 [mpls_iptunnel]
lwtunnel_xmit+0x18f/0x450
ip_finish_output2+0x867/0x2040
[ ... ] |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: libfc: Fix array index out of bound exception
Fix array index out of bound exception in fc_rport_prli_resp(). |
| In the Linux kernel, the following vulnerability has been resolved:
cifs: prevent NULL deref in cifs_compose_mount_options()
The optional @ref parameter might contain an NULL node_name, so
prevent dereferencing it in cifs_compose_mount_options().
Addresses-Coverity: 1476408 ("Explicit null dereferenced") |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Track subprog poke descriptors correctly and fix use-after-free
Subprograms are calling map_poke_track(), but on program release there is no
hook to call map_poke_untrack(). However, on program release, the aux memory
(and poke descriptor table) is freed even though we still have a reference to
it in the element list of the map aux data. When we run map_poke_run(), we then
end up accessing free'd memory, triggering KASAN in prog_array_map_poke_run():
[...]
[ 402.824689] BUG: KASAN: use-after-free in prog_array_map_poke_run+0xc2/0x34e
[ 402.824698] Read of size 4 at addr ffff8881905a7940 by task hubble-fgs/4337
[ 402.824705] CPU: 1 PID: 4337 Comm: hubble-fgs Tainted: G I 5.12.0+ #399
[ 402.824715] Call Trace:
[ 402.824719] dump_stack+0x93/0xc2
[ 402.824727] print_address_description.constprop.0+0x1a/0x140
[ 402.824736] ? prog_array_map_poke_run+0xc2/0x34e
[ 402.824740] ? prog_array_map_poke_run+0xc2/0x34e
[ 402.824744] kasan_report.cold+0x7c/0xd8
[ 402.824752] ? prog_array_map_poke_run+0xc2/0x34e
[ 402.824757] prog_array_map_poke_run+0xc2/0x34e
[ 402.824765] bpf_fd_array_map_update_elem+0x124/0x1a0
[...]
The elements concerned are walked as follows:
for (i = 0; i < elem->aux->size_poke_tab; i++) {
poke = &elem->aux->poke_tab[i];
[...]
The access to size_poke_tab is a 4 byte read, verified by checking offsets
in the KASAN dump:
[ 402.825004] The buggy address belongs to the object at ffff8881905a7800
which belongs to the cache kmalloc-1k of size 1024
[ 402.825008] The buggy address is located 320 bytes inside of
1024-byte region [ffff8881905a7800, ffff8881905a7c00)
The pahole output of bpf_prog_aux:
struct bpf_prog_aux {
[...]
/* --- cacheline 5 boundary (320 bytes) --- */
u32 size_poke_tab; /* 320 4 */
[...]
In general, subprograms do not necessarily manage their own data structures.
For example, BTF func_info and linfo are just pointers to the main program
structure. This allows reference counting and cleanup to be done on the latter
which simplifies their management a bit. The aux->poke_tab struct, however,
did not follow this logic. The initial proposed fix for this use-after-free
bug further embedded poke data tracking into the subprogram with proper
reference counting. However, Daniel and Alexei questioned why we were treating
these objects special; I agree, its unnecessary. The fix here removes the per
subprogram poke table allocation and map tracking and instead simply points
the aux->poke_tab pointer at the main programs poke table. This way, map
tracking is simplified to the main program and we do not need to manage them
per subprogram.
This also means, bpf_prog_free_deferred(), which unwinds the program reference
counting and kfrees objects, needs to ensure that we don't try to double free
the poke_tab when free'ing the subprog structures. This is easily solved by
NULL'ing the poke_tab pointer. The second detail is to ensure that per
subprogram JIT logic only does fixups on poke_tab[] entries it owns. To do
this, we add a pointer in the poke structure to point at the subprogram value
so JITs can easily check while walking the poke_tab structure if the current
entry belongs to the current program. The aux pointer is stable and therefore
suitable for such comparison. On the jit_subprogs() error path, we omit
cleaning up the poke->aux field because these are only ever referenced from
the JIT side, but on error we will never make it to the JIT, so its fine to
leave them dangling. Removing these pointers would complicate the error path
for no reason. However, we do need to untrack all poke descriptors from the
main program as otherwise they could race with the freeing of JIT memory from
the subprograms. Lastly, a748c6975dea3 ("bpf: propagate poke des
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix tail_call_reachable rejection for interpreter when jit failed
During testing of f263a81451c1 ("bpf: Track subprog poke descriptors correctly
and fix use-after-free") under various failure conditions, for example, when
jit_subprogs() fails and tries to clean up the program to be run under the
interpreter, we ran into the following freeze:
[...]
#127/8 tailcall_bpf2bpf_3:FAIL
[...]
[ 92.041251] BUG: KASAN: slab-out-of-bounds in ___bpf_prog_run+0x1b9d/0x2e20
[ 92.042408] Read of size 8 at addr ffff88800da67f68 by task test_progs/682
[ 92.043707]
[ 92.044030] CPU: 1 PID: 682 Comm: test_progs Tainted: G O 5.13.0-53301-ge6c08cb33a30-dirty #87
[ 92.045542] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014
[ 92.046785] Call Trace:
[ 92.047171] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.047773] ? __bpf_prog_run_args32+0x8b/0xb0
[ 92.048389] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.049019] ? ktime_get+0x117/0x130
[...] // few hundred [similar] lines more
[ 92.659025] ? ktime_get+0x117/0x130
[ 92.659845] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.660738] ? __bpf_prog_run_args32+0x8b/0xb0
[ 92.661528] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.662378] ? print_usage_bug+0x50/0x50
[ 92.663221] ? print_usage_bug+0x50/0x50
[ 92.664077] ? bpf_ksym_find+0x9c/0xe0
[ 92.664887] ? ktime_get+0x117/0x130
[ 92.665624] ? kernel_text_address+0xf5/0x100
[ 92.666529] ? __kernel_text_address+0xe/0x30
[ 92.667725] ? unwind_get_return_address+0x2f/0x50
[ 92.668854] ? ___bpf_prog_run+0x15d4/0x2e20
[ 92.670185] ? ktime_get+0x117/0x130
[ 92.671130] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.672020] ? __bpf_prog_run_args32+0x8b/0xb0
[ 92.672860] ? __bpf_prog_run_args64+0xc0/0xc0
[ 92.675159] ? ktime_get+0x117/0x130
[ 92.677074] ? lock_is_held_type+0xd5/0x130
[ 92.678662] ? ___bpf_prog_run+0x15d4/0x2e20
[ 92.680046] ? ktime_get+0x117/0x130
[ 92.681285] ? __bpf_prog_run32+0x6b/0x90
[ 92.682601] ? __bpf_prog_run64+0x90/0x90
[ 92.683636] ? lock_downgrade+0x370/0x370
[ 92.684647] ? mark_held_locks+0x44/0x90
[ 92.685652] ? ktime_get+0x117/0x130
[ 92.686752] ? lockdep_hardirqs_on+0x79/0x100
[ 92.688004] ? ktime_get+0x117/0x130
[ 92.688573] ? __cant_migrate+0x2b/0x80
[ 92.689192] ? bpf_test_run+0x2f4/0x510
[ 92.689869] ? bpf_test_timer_continue+0x1c0/0x1c0
[ 92.690856] ? rcu_read_lock_bh_held+0x90/0x90
[ 92.691506] ? __kasan_slab_alloc+0x61/0x80
[ 92.692128] ? eth_type_trans+0x128/0x240
[ 92.692737] ? __build_skb+0x46/0x50
[ 92.693252] ? bpf_prog_test_run_skb+0x65e/0xc50
[ 92.693954] ? bpf_prog_test_run_raw_tp+0x2d0/0x2d0
[ 92.694639] ? __fget_light+0xa1/0x100
[ 92.695162] ? bpf_prog_inc+0x23/0x30
[ 92.695685] ? __sys_bpf+0xb40/0x2c80
[ 92.696324] ? bpf_link_get_from_fd+0x90/0x90
[ 92.697150] ? mark_held_locks+0x24/0x90
[ 92.698007] ? lockdep_hardirqs_on_prepare+0x124/0x220
[ 92.699045] ? finish_task_switch+0xe6/0x370
[ 92.700072] ? lockdep_hardirqs_on+0x79/0x100
[ 92.701233] ? finish_task_switch+0x11d/0x370
[ 92.702264] ? __switch_to+0x2c0/0x740
[ 92.703148] ? mark_held_locks+0x24/0x90
[ 92.704155] ? __x64_sys_bpf+0x45/0x50
[ 92.705146] ? do_syscall_64+0x35/0x80
[ 92.706953] ? entry_SYSCALL_64_after_hwframe+0x44/0xae
[...]
Turns out that the program rejection from e411901c0b77 ("bpf: allow for tailcalls
in BPF subprograms for x64 JIT") is buggy since env->prog->aux->tail_call_reachable
is never true. Commit ebf7d1f508a7 ("bpf, x64: rework pro/epilogue and tailcall
handling in JIT") added a tracker into check_max_stack_depth() which propagates
the tail_call_reachable condition throughout the subprograms. This info is then
assigned to the subprogram's
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: PPC: Fix kvm_arch_vcpu_ioctl vcpu_load leak
vcpu_put is not called if the user copy fails. This can result in preempt
notifier corruption and crashes, among other issues. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: fix another slab-out-of-bounds in fib6_nh_flush_exceptions
While running the self-tests on a KASAN enabled kernel, I observed a
slab-out-of-bounds splat very similar to the one reported in
commit 821bbf79fe46 ("ipv6: Fix KASAN: slab-out-of-bounds Read in
fib6_nh_flush_exceptions").
We additionally need to take care of fib6_metrics initialization
failure when the caller provides an nh.
The fix is similar, explicitly free the route instead of calling
fib6_info_release on a half-initialized object. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Fix NULL dereference on XCOPY completion
CPU affinity control added with commit 39ae3edda325 ("scsi: target: core:
Make completion affinity configurable") makes target_complete_cmd() queue
work on a CPU based on se_tpg->se_tpg_wwn->cmd_compl_affinity state.
LIO's EXTENDED COPY worker is a special case in that read/write cmds are
dispatched using the global xcopy_pt_tpg, which carries a NULL se_tpg_wwn
pointer following initialization in target_xcopy_setup_pt().
The NULL xcopy_pt_tpg->se_tpg_wwn pointer is dereferenced on completion of
any EXTENDED COPY initiated read/write cmds. E.g using the libiscsi
SCSI.ExtendedCopy.Simple test:
BUG: kernel NULL pointer dereference, address: 00000000000001a8
RIP: 0010:target_complete_cmd+0x9d/0x130 [target_core_mod]
Call Trace:
fd_execute_rw+0x148/0x42a [target_core_file]
? __dynamic_pr_debug+0xa7/0xe0
? target_check_reservation+0x5b/0x940 [target_core_mod]
__target_execute_cmd+0x1e/0x90 [target_core_mod]
transport_generic_new_cmd+0x17c/0x330 [target_core_mod]
target_xcopy_issue_pt_cmd+0x9/0x60 [target_core_mod]
target_xcopy_read_source.isra.7+0x10b/0x1b0 [target_core_mod]
? target_check_fua+0x40/0x40 [target_core_mod]
? transport_complete_task_attr+0x130/0x130 [target_core_mod]
target_xcopy_do_work+0x61f/0xc00 [target_core_mod]
This fix makes target_complete_cmd() queue work on se_cmd->cpuid if
se_tpg_wwn is NULL. |
| In the Linux kernel, the following vulnerability has been resolved:
spi: bcm2835: Fix out-of-bounds access with more than 4 slaves
Commit 571e31fa60b3 ("spi: bcm2835: Cache CS register value for
->prepare_message()") limited the number of slaves to 3 at compile-time.
The limitation was necessitated by a statically-sized array prepare_cs[]
in the driver private data which contains a per-slave register value.
The commit sought to enforce the limitation at run-time by setting the
controller's num_chipselect to 3: Slaves with a higher chipselect are
rejected by spi_add_device().
However the commit neglected that num_chipselect only limits the number
of *native* chipselects. If GPIO chipselects are specified in the
device tree for more than 3 slaves, num_chipselect is silently raised by
of_spi_get_gpio_numbers() and the result are out-of-bounds accesses to
the statically-sized array prepare_cs[].
As a bandaid fix which is backportable to stable, raise the number of
allowed slaves to 24 (which "ought to be enough for anybody"), enforce
the limitation on slave ->setup and revert num_chipselect to 3 (which is
the number of native chipselects supported by the controller).
An upcoming for-next commit will allow an arbitrary number of slaves. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: seq: Fix race of snd_seq_timer_open()
The timer instance per queue is exclusive, and snd_seq_timer_open()
should have managed the concurrent accesses. It looks as if it's
checking the already existing timer instance at the beginning, but
it's not right, because there is no protection, hence any later
concurrent call of snd_seq_timer_open() may override the timer
instance easily. This may result in UAF, as the leftover timer
instance can keep running while the queue itself gets closed, as
spotted by syzkaller recently.
For avoiding the race, add a proper check at the assignment of
tmr->timeri again, and return -EBUSY if it's been already registered. |
| In the Linux kernel, the following vulnerability has been resolved:
tracing: Correct the length check which causes memory corruption
We've suffered from severe kernel crashes due to memory corruption on
our production environment, like,
Call Trace:
[1640542.554277] general protection fault: 0000 [#1] SMP PTI
[1640542.554856] CPU: 17 PID: 26996 Comm: python Kdump: loaded Tainted:G
[1640542.556629] RIP: 0010:kmem_cache_alloc+0x90/0x190
[1640542.559074] RSP: 0018:ffffb16faa597df8 EFLAGS: 00010286
[1640542.559587] RAX: 0000000000000000 RBX: 0000000000400200 RCX:
0000000006e931bf
[1640542.560323] RDX: 0000000006e931be RSI: 0000000000400200 RDI:
ffff9a45ff004300
[1640542.560996] RBP: 0000000000400200 R08: 0000000000023420 R09:
0000000000000000
[1640542.561670] R10: 0000000000000000 R11: 0000000000000000 R12:
ffffffff9a20608d
[1640542.562366] R13: ffff9a45ff004300 R14: ffff9a45ff004300 R15:
696c662f65636976
[1640542.563128] FS: 00007f45d7c6f740(0000) GS:ffff9a45ff840000(0000)
knlGS:0000000000000000
[1640542.563937] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[1640542.564557] CR2: 00007f45d71311a0 CR3: 000000189d63e004 CR4:
00000000003606e0
[1640542.565279] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[1640542.566069] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[1640542.566742] Call Trace:
[1640542.567009] anon_vma_clone+0x5d/0x170
[1640542.567417] __split_vma+0x91/0x1a0
[1640542.567777] do_munmap+0x2c6/0x320
[1640542.568128] vm_munmap+0x54/0x70
[1640542.569990] __x64_sys_munmap+0x22/0x30
[1640542.572005] do_syscall_64+0x5b/0x1b0
[1640542.573724] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[1640542.575642] RIP: 0033:0x7f45d6e61e27
James Wang has reproduced it stably on the latest 4.19 LTS.
After some debugging, we finally proved that it's due to ftrace
buffer out-of-bound access using a debug tool as follows:
[ 86.775200] BUG: Out-of-bounds write at addr 0xffff88aefe8b7000
[ 86.780806] no_context+0xdf/0x3c0
[ 86.784327] __do_page_fault+0x252/0x470
[ 86.788367] do_page_fault+0x32/0x140
[ 86.792145] page_fault+0x1e/0x30
[ 86.795576] strncpy_from_unsafe+0x66/0xb0
[ 86.799789] fetch_memory_string+0x25/0x40
[ 86.804002] fetch_deref_string+0x51/0x60
[ 86.808134] kprobe_trace_func+0x32d/0x3a0
[ 86.812347] kprobe_dispatcher+0x45/0x50
[ 86.816385] kprobe_ftrace_handler+0x90/0xf0
[ 86.820779] ftrace_ops_assist_func+0xa1/0x140
[ 86.825340] 0xffffffffc00750bf
[ 86.828603] do_sys_open+0x5/0x1f0
[ 86.832124] do_syscall_64+0x5b/0x1b0
[ 86.835900] entry_SYSCALL_64_after_hwframe+0x44/0xa9
commit b220c049d519 ("tracing: Check length before giving out
the filter buffer") adds length check to protect trace data
overflow introduced in 0fc1b09ff1ff, seems that this fix can't prevent
overflow entirely, the length check should also take the sizeof
entry->array[0] into account, since this array[0] is filled the
length of trace data and occupy addtional space and risk overflow. |
| In the Linux kernel, the following vulnerability has been resolved:
IB/mlx5: Fix initializing CQ fragments buffer
The function init_cq_frag_buf() can be called to initialize the current CQ
fragments buffer cq->buf, or the temporary cq->resize_buf that is filled
during CQ resize operation.
However, the offending commit started to use function get_cqe() for
getting the CQEs, the issue with this change is that get_cqe() always
returns CQEs from cq->buf, which leads us to initialize the wrong buffer,
and in case of enlarging the CQ we try to access elements beyond the size
of the current cq->buf and eventually hit a kernel panic.
[exception RIP: init_cq_frag_buf+103]
[ffff9f799ddcbcd8] mlx5_ib_resize_cq at ffffffffc0835d60 [mlx5_ib]
[ffff9f799ddcbdb0] ib_resize_cq at ffffffffc05270df [ib_core]
[ffff9f799ddcbdc0] llt_rdma_setup_qp at ffffffffc0a6a712 [llt]
[ffff9f799ddcbe10] llt_rdma_cc_event_action at ffffffffc0a6b411 [llt]
[ffff9f799ddcbe98] llt_rdma_client_conn_thread at ffffffffc0a6bb75 [llt]
[ffff9f799ddcbec8] kthread at ffffffffa66c5da1
[ffff9f799ddcbf50] ret_from_fork_nospec_begin at ffffffffa6d95ddd
Fix it by getting the needed CQE by calling mlx5_frag_buf_get_wqe() that
takes the correct source buffer as a parameter. |
| In the Linux kernel, the following vulnerability has been resolved:
NFS: Fix use-after-free in nfs4_init_client()
KASAN reports a use-after-free when attempting to mount two different
exports through two different NICs that belong to the same server.
Olga was able to hit this with kernels starting somewhere between 5.7
and 5.10, but I traced the patch that introduced the clear_bit() call to
4.13. So something must have changed in the refcounting of the clp
pointer to make this call to nfs_put_client() the very last one. |
| In the Linux kernel, the following vulnerability has been resolved:
udp: fix race between close() and udp_abort()
Kaustubh reported and diagnosed a panic in udp_lib_lookup().
The root cause is udp_abort() racing with close(). Both
racing functions acquire the socket lock, but udp{v6}_destroy_sock()
release it before performing destructive actions.
We can't easily extend the socket lock scope to avoid the race,
instead use the SOCK_DEAD flag to prevent udp_abort from doing
any action when the critical race happens.
Diagnosed-and-tested-by: Kaustubh Pandey <kapandey@codeaurora.org> |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: synproxy: Fix out of bounds when parsing TCP options
The TCP option parser in synproxy (synproxy_parse_options) could read
one byte out of bounds. When the length is 1, the execution flow gets
into the loop, reads one byte of the opcode, and if the opcode is
neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds
the length of 1.
This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack
out of bounds when parsing TCP options.").
v2 changes:
Added an early return when length < 0 to avoid calling
skb_header_pointer with negative length. |
| In the Linux kernel, the following vulnerability has been resolved:
mptcp: Fix out of bounds when parsing TCP options
The TCP option parser in mptcp (mptcp_get_options) could read one byte
out of bounds. When the length is 1, the execution flow gets into the
loop, reads one byte of the opcode, and if the opcode is neither
TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the
length of 1.
This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack
out of bounds when parsing TCP options."). |