From: Matthew Garrett <matthewgarrett@google.com>
To: jmorris@namei.org
Cc: linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, dhowells@redhat.com
Subject: [PATCH 24/27] bpf: Restrict kernel image access functions when the kernel is locked down
Date: Thu, 28 Feb 2019 15:12:00 -0800
Message-ID: <20190228231203.212359-24-matthewgarrett@google.com> (raw)
In-Reply-To: <20190228231203.212359-1-matthewgarrett@google.com>
From: David Howells <dhowells@redhat.com>
There are some bpf functions can be used to read kernel memory:
bpf_probe_read, bpf_probe_write_user and bpf_trace_printk. These allow
private keys in kernel memory (e.g. the hibernation image signing key) to
be read by an eBPF program and kernel memory to be altered without
restriction.
Completely prohibit the use of BPF when the kernel is locked down.
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: netdev@vger.kernel.org
cc: Chun-Yi Lee <jlee@suse.com>
cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
---
kernel/bpf/syscall.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 8577bb7f8be6..e78dbe5473c9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2593,6 +2593,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
return -EPERM;
+ if (kernel_is_locked_down("BPF"))
+ return -EPERM;
+
err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
if (err)
return err;
--
2.21.0.352.gf09ad66450-goog
next prev parent reply index
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 21:28 [PULL REQUEST] Lock down patches Matthew Garrett
2019-02-28 22:20 ` Mimi Zohar
2019-02-28 23:13 ` Matthew Garrett
2019-03-01 0:05 ` Mimi Zohar
2019-03-01 1:01 ` Matthew Garrett
2019-03-01 1:44 ` Mimi Zohar
2019-03-01 3:33 ` Matthew Garrett
2019-03-01 4:16 ` Mimi Zohar
2019-02-28 22:44 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 22:44 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:10 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 23:10 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:11 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 23:11 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:11 ` [PATCH 01/27] Add the ability to lock down access to the running kernel image Matthew Garrett
2019-02-28 23:11 ` [PATCH 02/27] Add a SysRq option to lift kernel lockdown Matthew Garrett
2019-02-28 23:11 ` [PATCH 03/27] Enforce module signatures if the kernel is locked down Matthew Garrett
2019-02-28 23:11 ` [PATCH 04/27] Restrict /dev/{mem,kmem,port} when " Matthew Garrett
2019-02-28 23:11 ` [PATCH 05/27] kexec_load: Disable at runtime if " Matthew Garrett
2019-02-28 23:11 ` [PATCH 06/27] Copy secure_boot flag in boot params across kexec reboot Matthew Garrett
2019-02-28 23:11 ` [PATCH 07/27] kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE Matthew Garrett
2019-02-28 23:11 ` [PATCH 08/27] kexec_file: Restrict at runtime if the kernel is locked down Matthew Garrett
2019-03-01 2:05 ` Mimi Zohar
2019-02-28 23:11 ` [PATCH 09/27] hibernate: Disable when " Matthew Garrett
2019-03-19 22:15 ` Pavel Machek
2019-02-28 23:11 ` [PATCH 10/27] uswsusp: " Matthew Garrett
2019-02-28 23:11 ` [PATCH 11/27] PCI: Lock down BAR access " Matthew Garrett
2019-02-28 23:11 ` [PATCH 12/27] x86: Lock down IO port " Matthew Garrett
2019-02-28 23:11 ` [PATCH 13/27] x86/msr: Restrict MSR " Matthew Garrett
2019-02-28 23:11 ` [PATCH 14/27] ACPI: Limit access to custom_method " Matthew Garrett
2019-02-28 23:11 ` [PATCH 15/27] acpi: Ignore acpi_rsdp kernel param when the kernel has been " Matthew Garrett
2019-02-28 23:11 ` [PATCH 16/27] acpi: Disable ACPI table override if the kernel is " Matthew Garrett
2019-02-28 23:11 ` [PATCH 17/27] acpi: Disable APEI error injection " Matthew Garrett
2019-02-28 23:11 ` [PATCH 18/27] Prohibit PCMCIA CIS storage when " Matthew Garrett
2019-02-28 23:11 ` [PATCH 19/27] Lock down TIOCSSERIAL Matthew Garrett
2019-02-28 23:11 ` [PATCH 20/27] Lock down module params that specify hardware parameters (eg. ioport) Matthew Garrett
2019-02-28 23:11 ` [PATCH 21/27] x86/mmiotrace: Lock down the testmmiotrace module Matthew Garrett
2019-02-28 23:11 ` [PATCH 22/27] Lock down /proc/kcore Matthew Garrett
2019-02-28 23:11 ` [PATCH 23/27] Lock down kprobes Matthew Garrett
2019-02-28 23:12 ` Matthew Garrett [this message]
2019-02-28 23:12 ` [PATCH 25/27] Lock down perf Matthew Garrett
2019-02-28 23:12 ` [PATCH 26/27] debugfs: Restrict debugfs when the kernel is locked down Matthew Garrett
2019-02-28 23:12 ` [PATCH 27/27] lockdown: Print current->comm in restriction messages Matthew Garrett
2019-02-28 23:24 ` [PULL REQUEST] Lock down patches Randy Dunlap
2019-03-04 22:10 ` Matthew Garrett
2019-03-06 23:58 [PULL REQUEST] Kernel lockdown patches for 5.2 Matthew Garrett
2019-03-06 23:59 ` [PATCH 24/27] bpf: Restrict kernel image access functions when the kernel is locked down Matthew Garrett
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