[S390] secure computing arch backend
Enable secure computing on s390 as well.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 2eca5fe..1094787 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -567,6 +567,24 @@
the KVM hypervisor. This will add detection for KVM as well as a
virtio transport. If KVM is detected, the virtio console will be
the default console.
+
+config SECCOMP
+ bool "Enable seccomp to safely compute untrusted bytecode"
+ depends on PROC_FS
+ default y
+ help
+ This kernel feature is useful for number crunching applications
+ that may need to compute untrusted bytecode during their
+ execution. By using pipes or other transports made available to
+ the process as file descriptors supporting the read/write
+ syscalls, it's possible to isolate those applications in
+ their own address space using seccomp. Once seccomp is
+ enabled via /proc/<pid>/seccomp, it cannot be disabled
+ and the task is only allowed to execute a few safe syscalls
+ defined by each seccomp mode.
+
+ If unsure, say Y.
+
endmenu
source "net/Kconfig"
diff --git a/arch/s390/include/asm/seccomp.h b/arch/s390/include/asm/seccomp.h
new file mode 100644
index 0000000..781a9cf
--- /dev/null
+++ b/arch/s390/include/asm/seccomp.h
@@ -0,0 +1,16 @@
+#ifndef _ASM_S390_SECCOMP_H
+#define _ASM_S390_SECCOMP_H
+
+#include <linux/unistd.h>
+
+#define __NR_seccomp_read __NR_read
+#define __NR_seccomp_write __NR_write
+#define __NR_seccomp_exit __NR_exit
+#define __NR_seccomp_sigreturn __NR_sigreturn
+
+#define __NR_seccomp_read_32 __NR_read
+#define __NR_seccomp_write_32 __NR_write
+#define __NR_seccomp_exit_32 __NR_exit
+#define __NR_seccomp_sigreturn_32 __NR_sigreturn
+
+#endif /* _ASM_S390_SECCOMP_H */
diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h
index 461f2ab..2f86653 100644
--- a/arch/s390/include/asm/thread_info.h
+++ b/arch/s390/include/asm/thread_info.h
@@ -83,14 +83,15 @@
/*
* thread information flags bit numbers
*/
-#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
#define TIF_SIGPENDING 2 /* signal pending */
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
#define TIF_RESTART_SVC 4 /* restart svc with new svc number */
-#define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */
#define TIF_SINGLE_STEP 6 /* deliver sigtrap on return to user */
#define TIF_MCCK_PENDING 7 /* machine check handling is pending */
+#define TIF_SYSCALL_TRACE 8 /* syscall trace active */
+#define TIF_SYSCALL_AUDIT 9 /* syscall auditing active */
+#define TIF_SECCOMP 10 /* secure computing */
#define TIF_USEDFPU 16 /* FPU was used by this task this quantum (SMP) */
#define TIF_POLLING_NRFLAG 17 /* true if poll_idle() is polling
TIF_NEED_RESCHED */
@@ -99,15 +100,16 @@
#define TIF_RESTORE_SIGMASK 20 /* restore signal mask in do_signal() */
#define TIF_FREEZE 21 /* thread is freezing for suspend */
-#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
#define _TIF_RESTART_SVC (1<<TIF_RESTART_SVC)
-#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SINGLE_STEP (1<<TIF_SINGLE_STEP)
#define _TIF_MCCK_PENDING (1<<TIF_MCCK_PENDING)
+#define _TIF_SYSCALL_TRACE (1<<TIF_SYSCALL_TRACE)
+#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
+#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_USEDFPU (1<<TIF_USEDFPU)
#define _TIF_POLLING_NRFLAG (1<<TIF_POLLING_NRFLAG)
#define _TIF_31BIT (1<<TIF_31BIT)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index f3e2759..db25cdc 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -53,6 +53,7 @@
_TIF_MCCK_PENDING | _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
_TIF_MCCK_PENDING)
+_TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | _TIF_SECCOMP>>8)
STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE = 1 << STACK_SHIFT
@@ -265,7 +266,7 @@
sth %r7,SP_SVCNR(%r15)
sll %r7,2 # svc number *4
l %r8,BASED(.Lsysc_table)
- tm __TI_flags+3(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
+ tm __TI_flags+2(%r9),_TIF_SYSCALL
l %r8,0(%r7,%r8) # get system call addr.
bnz BASED(sysc_tracesys)
basr %r14,%r8 # call sys_xxxx
@@ -405,7 +406,7 @@
basr %r14,%r8 # call sys_xxx
st %r2,SP_R2(%r15) # store return value
sysc_tracenogo:
- tm __TI_flags+3(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
+ tm __TI_flags+2(%r9),_TIF_SYSCALL
bz BASED(sysc_return)
l %r1,BASED(.Ltrace_exit)
la %r2,SP_PTREGS(%r15) # load pt_regs
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index 84a1058..3cec9b5 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -56,6 +56,7 @@
_TIF_MCCK_PENDING | _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
_TIF_MCCK_PENDING)
+_TIF_SYSCALL = (_TIF_SYSCALL_TRACE>>8 | _TIF_SYSCALL_AUDIT>>8 | _TIF_SECCOMP>>8)
#define BASED(name) name-system_call(%r13)
@@ -260,7 +261,7 @@
larl %r10,sys_call_table_emu # use 31 bit emulation system calls
sysc_noemu:
#endif
- tm __TI_flags+7(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
+ tm __TI_flags+6(%r9),_TIF_SYSCALL
lgf %r8,0(%r7,%r10) # load address of system call routine
jnz sysc_tracesys
basr %r14,%r8 # call sys_xxxx
@@ -391,7 +392,7 @@
basr %r14,%r8 # call sys_xxx
stg %r2,SP_R2(%r15) # store return value
sysc_tracenogo:
- tm __TI_flags+7(%r9),(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT)
+ tm __TI_flags+6(%r9),_TIF_SYSCALL
jz sysc_return
la %r2,SP_PTREGS(%r15) # load pt_regs
larl %r14,sysc_return # return point is sysc_return
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 99eef17..b6fc1ae 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -36,7 +36,8 @@
#include <linux/elf.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
-#include <linux/compat.h>
+#include <linux/seccomp.h>
+#include <asm/compat.h>
#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
@@ -640,6 +641,9 @@
{
long ret;
+ /* Do the secure computing check first. */
+ secure_computing(regs->gprs[2]);
+
/*
* The sysc_tracesys code in entry.S stored the system
* call number to gprs[2].