linux/kernel
Stanislav Fomichev 772412176f bpf: Allow rewriting to ports under ip_unprivileged_port_start
At the moment, BPF_CGROUP_INET{4,6}_BIND hooks can rewrite user_port
to the privileged ones (< ip_unprivileged_port_start), but it will
be rejected later on in the __inet_bind or __inet6_bind.

Let's add another return value to indicate that CAP_NET_BIND_SERVICE
check should be ignored. Use the same idea as we currently use
in cgroup/egress where bit #1 indicates CN. Instead, for
cgroup/bind{4,6}, bit #1 indicates that CAP_NET_BIND_SERVICE should
be bypassed.

v5:
- rename flags to be less confusing (Andrey Ignatov)
- rework BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY to work on flags
  and accept BPF_RET_SET_CN (no behavioral changes)

v4:
- Add missing IPv6 support (Martin KaFai Lau)

v3:
- Update description (Martin KaFai Lau)
- Fix capability restore in selftest (Martin KaFai Lau)

v2:
- Switch to explicit return code (Martin KaFai Lau)

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrey Ignatov <rdna@fb.com>
Link: https://lore.kernel.org/bpf/20210127193140.3170382-1-sdf@google.com
2021-01-27 18:18:15 -08:00
..
bpf bpf: Allow rewriting to ports under ip_unprivileged_port_start 2021-01-27 18:18:15 -08:00
cgroup
configs
debug
dma
entry
events perf: Add build id data in mmap2 event 2021-01-14 19:29:58 -08:00
gcov
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.gitignore
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audit.c
audit.h
audit_fsnotify.c
audit_tree.c
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
compat.c
configs.c
context_tracking.c
cpu.c
cpu_pm.c
crash_core.c
crash_dump.c
cred.c
delayacct.c
dma.c
exec_domain.c
exit.c
extable.c
fail_function.c
fork.c
freezer.c
futex.c
gen_kheaders.sh
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iomem.c
irq_work.c
jump_label.c
kallsyms.c
kcmp.c
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kthread.c
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module.c
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nsproxy.c
padata.c
panic.c
params.c
pid.c
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profile.c
ptrace.c
range.c
reboot.c
regset.c
relay.c
resource.c
resource_kunit.c
rseq.c
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scs.c
seccomp.c
signal.c
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smpboot.c
smpboot.h
softirq.c
stackleak.c
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sys.c
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task_work.c
taskstats.c
test_kprobes.c
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ucount.c
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user.c
user_namespace.c
usermode_driver.c
utsname.c
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watch_queue.c
watchdog.c
watchdog_hld.c
workqueue.c
workqueue_internal.h