tile: enable full SECCOMP support
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 9def1f5..2ba12d7 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -32,6 +32,7 @@
select EDAC_SUPPORT
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
+ select HAVE_ARCH_SECCOMP_FILTER
# FIXME: investigate whether we need/want these options.
# select HAVE_IOREMAP_PROT
@@ -221,6 +222,22 @@
If enabled, the kernel will support running TILE-Gx binaries
that were built with the -m32 option.
+config SECCOMP
+ bool "Enable seccomp to safely compute untrusted bytecode"
+ depends on PROC_FS
+ 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 prctl, it cannot be disabled and the task is only
+ allowed to execute a few safe syscalls defined by each seccomp
+ mode.
+
+ If unsure, say N.
+
config SYSVIPC_COMPAT
def_bool y
depends on COMPAT && SYSVIPC
diff --git a/arch/tile/include/asm/Kbuild b/arch/tile/include/asm/Kbuild
index d8a8431..ba35c41 100644
--- a/arch/tile/include/asm/Kbuild
+++ b/arch/tile/include/asm/Kbuild
@@ -28,6 +28,7 @@
generic-y += posix_types.h
generic-y += preempt.h
generic-y += resource.h
+generic-y += seccomp.h
generic-y += sembuf.h
generic-y += serial.h
generic-y += shmbuf.h
diff --git a/arch/tile/include/asm/elf.h b/arch/tile/include/asm/elf.h
index 41d9878..c505d77 100644
--- a/arch/tile/include/asm/elf.h
+++ b/arch/tile/include/asm/elf.h
@@ -22,6 +22,7 @@
#include <arch/chip.h>
#include <linux/ptrace.h>
+#include <linux/elf-em.h>
#include <asm/byteorder.h>
#include <asm/page.h>
@@ -30,9 +31,6 @@
#define ELF_NGREG (sizeof(struct pt_regs) / sizeof(elf_greg_t))
typedef elf_greg_t elf_gregset_t[ELF_NGREG];
-#define EM_TILEPRO 188
-#define EM_TILEGX 191
-
/* Provide a nominal data structure. */
#define ELF_NFPREG 0
typedef double elf_fpreg_t;
diff --git a/arch/tile/include/asm/syscall.h b/arch/tile/include/asm/syscall.h
index 9644b88..373d730 100644
--- a/arch/tile/include/asm/syscall.h
+++ b/arch/tile/include/asm/syscall.h
@@ -20,6 +20,8 @@
#include <linux/sched.h>
#include <linux/err.h>
+#include <linux/audit.h>
+#include <linux/compat.h>
#include <arch/abi.h>
/* The array of function pointers for syscalls. */
@@ -61,7 +63,15 @@
struct pt_regs *regs,
int error, long val)
{
- regs->regs[0] = (long) error ?: val;
+ if (error) {
+ /* R0 is the passed-in negative error, R1 is positive. */
+ regs->regs[0] = error;
+ regs->regs[1] = -error;
+ } else {
+ /* R1 set to zero to indicate no error. */
+ regs->regs[0] = val;
+ regs->regs[1] = 0;
+ }
}
static inline void syscall_get_arguments(struct task_struct *task,
@@ -82,4 +92,20 @@
memcpy(®s[i], args, n * sizeof(args[0]));
}
+/*
+ * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
+ * tile has the same system calls both on little- and big- endian.
+ */
+static inline int syscall_get_arch(void)
+{
+ if (is_compat_task())
+ return AUDIT_ARCH_TILEGX32;
+
+#ifdef CONFIG_TILEGX
+ return AUDIT_ARCH_TILEGX;
+#else
+ return AUDIT_ARCH_TILEPRO;
+#endif
+}
+
#endif /* _ASM_TILE_SYSCALL_H */
diff --git a/arch/tile/kernel/intvec_32.S b/arch/tile/kernel/intvec_32.S
index cdbda45..fbbe2ea 100644
--- a/arch/tile/kernel/intvec_32.S
+++ b/arch/tile/kernel/intvec_32.S
@@ -1224,6 +1224,7 @@
jal do_syscall_trace_enter
}
FEEDBACK_REENTER(handle_syscall)
+ blz r0, .Lsyscall_sigreturn_skip
/*
* We always reload our registers from the stack at this
diff --git a/arch/tile/kernel/intvec_64.S b/arch/tile/kernel/intvec_64.S
index 800b91d..58964d2 100644
--- a/arch/tile/kernel/intvec_64.S
+++ b/arch/tile/kernel/intvec_64.S
@@ -1247,6 +1247,7 @@
jal do_syscall_trace_enter
}
FEEDBACK_REENTER(handle_syscall)
+ bltz r0, .Lsyscall_sigreturn_skip
/*
* We always reload our registers from the stack at this
diff --git a/arch/tile/kernel/ptrace.c b/arch/tile/kernel/ptrace.c
index f84eed8..bdc126f 100644
--- a/arch/tile/kernel/ptrace.c
+++ b/arch/tile/kernel/ptrace.c
@@ -262,6 +262,9 @@
if (work & _TIF_NOHZ)
user_exit();
+ if (secure_computing() == -1)
+ return -1;
+
if (work & _TIF_SYSCALL_TRACE) {
if (tracehook_report_syscall_entry(regs))
regs->regs[TREG_SYSCALL_NR] = -1;