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Linux sandbox: add space for 8 parameters to the Syscall() class
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On some architectures (Mips for example) syscalls can take more
than six parameters.

Add support for 8 native-size parameters in Syscall::Call()

BUG=369594
TEST= sandbox_linux_unittests

Review URL: https://codereview.chromium.org/357323003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281823 0039d316-1c4b-4281-b951-d872f2087c98
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nedeljko.babic@imgtec.com committed Jul 8, 2014
1 parent b856433 commit 33447b3
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Showing 3 changed files with 81 additions and 23 deletions.
1 change: 1 addition & 0 deletions AUTHORS
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Original file line number Diff line number Diff line change
Expand Up @@ -276,6 +276,7 @@ Naveen Bobbili <naveenbobbili@motorola.com>
Naveen Bobbili <qghc36@motorola.com>
Naveen Kumar S G <naveensg@samsung.com>
Nayan Kumar K <qtc746@motorola.com>
Nedeljko Babic <nedeljko.babic@imgtec.com>
Nikhil Bansal <n.bansal@samsung.com>
Nikita Ofitserov <himikof@gmail.com>
Ningxin Hu <ningxin.hu@intel.com>
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11 changes: 10 additions & 1 deletion sandbox/linux/seccomp-bpf/syscall.cc
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Expand Up @@ -8,6 +8,7 @@
#include <errno.h>

#include "base/basictypes.h"
#include "base/logging.h"

namespace sandbox {

Expand Down Expand Up @@ -181,7 +182,9 @@ intptr_t Syscall::Call(int nr,
intptr_t p2,
intptr_t p3,
intptr_t p4,
intptr_t p5) {
intptr_t p5,
intptr_t p6,
intptr_t p7) {
// We rely on "intptr_t" to be the exact size as a "void *". This is
// typically true, but just in case, we add a check. The language
// specification allows platforms some leeway in cases, where
Expand All @@ -192,6 +195,12 @@ intptr_t Syscall::Call(int nr,
COMPILE_ASSERT(sizeof(void*) == sizeof(intptr_t),
pointer_types_and_intptr_must_be_exactly_the_same_size);

// TODO(nedeljko): Enable use of more than six parameters on architectures
// where that makes sense.
DCHECK_EQ(p6, 0) << " Support for syscalls with more than six arguments not "
"added for this architecture";
DCHECK_EQ(p7, 0) << " Support for syscalls with more than six arguments not "
"added for this architecture";
const intptr_t args[6] = {p0, p1, p2, p3, p4, p5};

// Invoke our file-scope assembly code. The constraints have been picked
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92 changes: 70 additions & 22 deletions sandbox/linux/seccomp-bpf/syscall.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,21 +16,8 @@ namespace sandbox {
// low-level control.
class SANDBOX_EXPORT Syscall {
public:
// This performs system call |nr| with the arguments p0 to p5 from a constant
// userland address, which is for instance observable by seccomp-bpf filters.
// The constant userland address from which these system calls are made will
// be returned if |nr| is passed as -1.
// On error, this function will return a value between -1 and -4095 which
// should be interpreted as -errno.
static intptr_t Call(int nr,
intptr_t p0,
intptr_t p1,
intptr_t p2,
intptr_t p3,
intptr_t p4,
intptr_t p5);

// System calls can take up to six parameters. Traditionally, glibc
// System calls can take up to six parameters (up to eight on some
// architectures). Traditionally, glibc
// implements this property by using variadic argument lists. This works, but
// confuses modern tools such as valgrind, because we are nominally passing
// uninitialized data whenever we call through this function and pass less
Expand All @@ -41,6 +28,47 @@ class SANDBOX_EXPORT Syscall {
// necessary.
// We have to use C-style cast operators as we want to be able to accept both
// integer and pointer types.
template <class T0,
class T1,
class T2,
class T3,
class T4,
class T5,
class T6,
class T7>
static inline intptr_t
Call(int nr, T0 p0, T1 p1, T2 p2, T3 p3, T4 p4, T5 p5, T6 p6, T7 p7) {
return Call(nr,
(intptr_t)p0,
(intptr_t)p1,
(intptr_t)p2,
(intptr_t)p3,
(intptr_t)p4,
(intptr_t)p5,
(intptr_t)p6,
(intptr_t)p7);
}

template <class T0,
class T1,
class T2,
class T3,
class T4,
class T5,
class T6>
static inline intptr_t
Call(int nr, T0 p0, T1 p1, T2 p2, T3 p3, T4 p4, T5 p5, T6 p6) {
return Call(nr,
(intptr_t)p0,
(intptr_t)p1,
(intptr_t)p2,
(intptr_t)p3,
(intptr_t)p4,
(intptr_t)p5,
(intptr_t)p6,
0);
}

template <class T0, class T1, class T2, class T3, class T4, class T5>
static inline intptr_t
Call(int nr, T0 p0, T1 p1, T2 p2, T3 p3, T4 p4, T5 p5) {
Expand All @@ -50,37 +78,57 @@ class SANDBOX_EXPORT Syscall {
(intptr_t)p2,
(intptr_t)p3,
(intptr_t)p4,
(intptr_t)p5);
(intptr_t)p5,
0,
0);
}

template <class T0, class T1, class T2, class T3, class T4>
static inline intptr_t Call(int nr, T0 p0, T1 p1, T2 p2, T3 p3, T4 p4) {
return Call(nr, p0, p1, p2, p3, p4, 0);
return Call(nr, p0, p1, p2, p3, p4, 0, 0, 0);
}

template <class T0, class T1, class T2, class T3>
static inline intptr_t Call(int nr, T0 p0, T1 p1, T2 p2, T3 p3) {
return Call(nr, p0, p1, p2, p3, 0, 0);
return Call(nr, p0, p1, p2, p3, 0, 0, 0, 0);
}

template <class T0, class T1, class T2>
static inline intptr_t Call(int nr, T0 p0, T1 p1, T2 p2) {
return Call(nr, p0, p1, p2, 0, 0, 0);
return Call(nr, p0, p1, p2, 0, 0, 0, 0, 0);
}

template <class T0, class T1>
static inline intptr_t Call(int nr, T0 p0, T1 p1) {
return Call(nr, p0, p1, 0, 0, 0, 0);
return Call(nr, p0, p1, 0, 0, 0, 0, 0, 0);
}

template <class T0>
static inline intptr_t Call(int nr, T0 p0) {
return Call(nr, p0, 0, 0, 0, 0, 0);
return Call(nr, p0, 0, 0, 0, 0, 0, 0, 0);
}

static inline intptr_t Call(int nr) { return Call(nr, 0, 0, 0, 0, 0, 0); }
static inline intptr_t Call(int nr) {
return Call(nr, 0, 0, 0, 0, 0, 0, 0, 0);
}

private:
// This performs system call |nr| with the arguments p0 to p7 from a constant
// userland address, which is for instance observable by seccomp-bpf filters.
// The constant userland address from which these system calls are made will
// be returned if |nr| is passed as -1.
// On error, this function will return a value between -1 and -4095 which
// should be interpreted as -errno.
static intptr_t Call(int nr,
intptr_t p0,
intptr_t p1,
intptr_t p2,
intptr_t p3,
intptr_t p4,
intptr_t p5,
intptr_t p6,
intptr_t p7);

DISALLOW_IMPLICIT_CONSTRUCTORS(Syscall);
};

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