From: David Howells <dhowells@redhat.com> To: torvalds@linux-foundation.org Cc: linux-man@vger.kernel.org, linux-api@vger.kernel.org, jmorris@namei.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-security-module@vger.kernel.org Subject: [PATCH 22/24] bpf: Restrict kernel image access functions when the kernel is locked down Date: Wed, 11 Apr 2018 17:27:03 +0100 [thread overview] Message-ID: <152346402306.4030.13915529680179697046.stgit@warthog.procyon.org.uk> (raw) In-Reply-To: <152346387861.4030.4408662483445703127.stgit@warthog.procyon.org.uk> 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. 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 0244973ee544..7457f2676c6d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2031,6 +2031,9 @@ 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 = check_uarg_tail_zero(uattr, sizeof(attr), size); if (err) return err;
WARNING: multiple messages have this Message-ID (diff)
From: dhowells@redhat.com (David Howells) To: linux-security-module@vger.kernel.org Subject: [PATCH 22/24] bpf: Restrict kernel image access functions when the kernel is locked down Date: Wed, 11 Apr 2018 17:27:03 +0100 [thread overview] Message-ID: <152346402306.4030.13915529680179697046.stgit@warthog.procyon.org.uk> (raw) In-Reply-To: <152346387861.4030.4408662483445703127.stgit@warthog.procyon.org.uk> 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. 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 at 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 0244973ee544..7457f2676c6d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2031,6 +2031,9 @@ 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 = check_uarg_tail_zero(uattr, sizeof(attr), size); if (err) return err; -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2018-04-11 16:27 UTC|newest] Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-11 16:24 [PATCH 00/24] security: Add kernel lockdown David Howells 2018-04-11 16:24 ` David Howells 2018-04-11 16:24 ` [PATCH 01/24] Add the ability to lock down access to the running kernel image David Howells 2018-04-11 16:24 ` David Howells 2018-04-11 16:44 ` Jann Horn 2018-04-11 16:44 ` Jann Horn 2018-04-11 17:37 ` Randy Dunlap 2018-04-11 17:37 ` Randy Dunlap 2018-04-11 18:50 ` Miguel Ojeda 2018-04-11 18:50 ` Miguel Ojeda 2018-04-11 19:56 ` Greg KH 2018-04-11 19:56 ` Greg KH 2018-04-11 17:49 ` David Howells 2018-04-11 17:49 ` David Howells 2018-04-11 18:09 ` Linus Torvalds 2018-04-11 18:09 ` Linus Torvalds 2018-04-11 18:35 ` Justin Forbes 2018-04-11 18:35 ` Justin Forbes 2018-04-11 21:05 ` Jordan Glover 2018-04-11 21:05 ` Jordan Glover 2018-04-11 22:38 ` Linus Torvalds 2018-04-11 22:38 ` Linus Torvalds 2018-04-12 13:09 ` Justin Forbes 2018-04-12 13:09 ` Justin Forbes 2018-04-12 16:52 ` Linus Torvalds 2018-04-12 16:52 ` Linus Torvalds 2018-04-12 2:57 ` Andy Lutomirski 2018-04-12 2:57 ` Andy Lutomirski 2018-04-11 16:24 ` [PATCH 02/24] Add a SysRq option to lift kernel lockdown David Howells 2018-04-11 16:24 ` David Howells 2018-04-11 17:05 ` Jann Horn 2018-04-11 17:05 ` Jann Horn 2018-04-13 20:22 ` Pavel Machek 2018-04-11 16:24 ` [PATCH 03/24] ima: require secure_boot rules in lockdown mode David Howells 2018-04-11 16:24 ` David Howells 2018-04-11 16:25 ` [PATCH 04/24] Enforce module signatures if the kernel is locked down David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:25 ` [PATCH 05/24] Restrict /dev/{mem, kmem, port} when " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:25 ` [PATCH 06/24] kexec_load: Disable at runtime if " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 19:00 ` Eric W. Biederman 2018-04-11 19:00 ` Eric W. Biederman 2018-04-11 20:09 ` Mimi Zohar 2018-04-11 20:09 ` Mimi Zohar 2018-04-12 11:38 ` Mimi Zohar 2018-04-12 11:38 ` Mimi Zohar 2018-04-11 20:05 ` David Howells 2018-04-11 20:05 ` David Howells 2018-04-11 20:05 ` David Howells 2018-04-11 16:25 ` [PATCH 07/24] hibernate: Disable when " David Howells 2018-04-11 16:25 ` David Howells 2018-04-13 20:22 ` Pavel Machek 2018-04-19 14:38 ` David Howells 2018-04-19 14:38 ` David Howells 2018-04-22 14:34 ` Andy Lutomirski 2018-04-22 14:34 ` Andy Lutomirski 2018-04-26 7:26 ` Pavel Machek 2018-04-26 7:34 ` Rafael J. Wysocki 2018-04-26 7:34 ` Rafael J. Wysocki 2018-04-26 8:20 ` Jiri Kosina 2018-04-26 8:20 ` Jiri Kosina 2018-05-23 8:46 ` joeyli 2018-05-23 8:46 ` joeyli 2018-04-11 16:25 ` [PATCH 08/24] uswsusp: " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:25 ` [PATCH 09/24] PCI: Lock down BAR access " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:25 ` [PATCH 10/24] x86: Lock down IO port " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:25 ` [PATCH 11/24] x86/msr: Restrict MSR " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:25 ` [PATCH 12/24] ACPI: Limit access to custom_method " David Howells 2018-04-11 16:25 ` David Howells 2018-04-11 16:26 ` [PATCH 13/24] acpi: Ignore acpi_rsdp kernel param when the kernel has been " David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 14/24] acpi: Disable ACPI table override if the kernel is " David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 15/24] acpi: Disable APEI error injection " David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 16/24] Prohibit PCMCIA CIS storage when " David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 17/24] Lock down TIOCSSERIAL David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 18/24] Lock down module params that specify hardware parameters (eg. ioport) David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 17:22 ` Randy Dunlap 2018-04-11 17:22 ` Randy Dunlap 2018-04-11 16:26 ` [PATCH 19/24] x86/mmiotrace: Lock down the testmmiotrace module David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 20/24] Lock down /proc/kcore David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:26 ` [PATCH 21/24] Lock down kprobes David Howells 2018-04-11 16:26 ` David Howells 2018-04-11 16:27 ` David Howells [this message] 2018-04-11 16:27 ` [PATCH 22/24] bpf: Restrict kernel image access functions when the kernel is locked down David Howells 2018-04-11 16:27 ` [PATCH 23/24] Lock down perf David Howells 2018-04-11 16:27 ` David Howells 2018-04-11 16:27 ` [PATCH 24/24] debugfs: Restrict debugfs when the kernel is locked down David Howells 2018-04-11 16:27 ` David Howells 2018-04-11 17:26 ` Randy Dunlap 2018-04-11 17:26 ` Randy Dunlap 2018-04-11 18:50 ` Eric W. Biederman 2018-04-11 18:50 ` Eric W. Biederman 2018-04-11 19:54 ` Greg KH 2018-04-11 19:54 ` Greg KH 2018-04-11 20:08 ` David Howells 2018-04-11 20:08 ` David Howells 2018-04-11 20:08 ` David Howells 2018-04-11 20:09 ` David Howells 2018-04-11 20:09 ` David Howells 2018-04-11 20:33 ` Greg KH 2018-04-11 20:33 ` Greg KH 2018-04-12 2:54 ` Andy Lutomirski 2018-04-12 2:54 ` Andy Lutomirski 2018-04-12 8:23 ` Greg KH 2018-04-12 8:23 ` Greg KH 2018-04-12 14:19 ` Andy Lutomirski 2018-04-12 14:19 ` Andy Lutomirski 2018-04-13 20:22 ` Pavel Machek 2018-04-19 14:35 ` David Howells 2018-04-19 14:35 ` David Howells 2018-05-10 11:01 ` Pavel Machek
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