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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-24 05:04:00 +08:00
linux-next/kernel/uid16.c
OGAWA Hirofumi 5a7b46b369 [PATCH] Add more prevent_tail_call()
Those also break userland regs like following.

   00000000 <sys_chown16>:
      0:	0f b7 44 24 0c       	movzwl 0xc(%esp),%eax
      5:	83 ca ff             	or     $0xffffffff,%edx
      8:	0f b7 4c 24 08       	movzwl 0x8(%esp),%ecx
      d:	66 83 f8 ff          	cmp    $0xffffffff,%ax
     11:	0f 44 c2             	cmove  %edx,%eax
     14:	66 83 f9 ff          	cmp    $0xffffffff,%cx
     18:	0f 45 d1             	cmovne %ecx,%edx
     1b:	89 44 24 0c          	mov    %eax,0xc(%esp)
     1f:	89 54 24 08          	mov    %edx,0x8(%esp)
     23:	e9 fc ff ff ff       	jmp    24 <sys_chown16+0x24>

where the tailcall at the end overwrites the incoming stack-frame.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
[ I would _really_ like to have a way to tell gcc about calling
  conventions. The "prevent_tail_call()" macro is pretty ugly ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-19 16:27:18 -07:00

231 lines
5.1 KiB
C

/*
* Wrapper functions for 16bit uid back compatibility. All nicely tied
* together in the faint hope we can take the out in five years time.
*/
#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
#include <linux/smp_lock.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
asmlinkage long sys_chown16(const char __user * filename, old_uid_t user, old_gid_t group)
{
long ret = sys_chown(filename, low2highuid(user), low2highgid(group));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_lchown16(const char __user * filename, old_uid_t user, old_gid_t group)
{
long ret = sys_lchown(filename, low2highuid(user), low2highgid(group));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_fchown16(unsigned int fd, old_uid_t user, old_gid_t group)
{
long ret = sys_fchown(fd, low2highuid(user), low2highgid(group));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_setregid16(old_gid_t rgid, old_gid_t egid)
{
long ret = sys_setregid(low2highgid(rgid), low2highgid(egid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_setgid16(old_gid_t gid)
{
long ret = sys_setgid(low2highgid(gid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_setreuid16(old_uid_t ruid, old_uid_t euid)
{
long ret = sys_setreuid(low2highuid(ruid), low2highuid(euid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_setuid16(old_uid_t uid)
{
long ret = sys_setuid(low2highuid(uid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_setresuid16(old_uid_t ruid, old_uid_t euid, old_uid_t suid)
{
long ret = sys_setresuid(low2highuid(ruid), low2highuid(euid),
low2highuid(suid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_getresuid16(old_uid_t __user *ruid, old_uid_t __user *euid, old_uid_t __user *suid)
{
int retval;
if (!(retval = put_user(high2lowuid(current->uid), ruid)) &&
!(retval = put_user(high2lowuid(current->euid), euid)))
retval = put_user(high2lowuid(current->suid), suid);
return retval;
}
asmlinkage long sys_setresgid16(old_gid_t rgid, old_gid_t egid, old_gid_t sgid)
{
long ret = sys_setresgid(low2highgid(rgid), low2highgid(egid),
low2highgid(sgid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_getresgid16(old_gid_t __user *rgid, old_gid_t __user *egid, old_gid_t __user *sgid)
{
int retval;
if (!(retval = put_user(high2lowgid(current->gid), rgid)) &&
!(retval = put_user(high2lowgid(current->egid), egid)))
retval = put_user(high2lowgid(current->sgid), sgid);
return retval;
}
asmlinkage long sys_setfsuid16(old_uid_t uid)
{
long ret = sys_setfsuid(low2highuid(uid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
asmlinkage long sys_setfsgid16(old_gid_t gid)
{
long ret = sys_setfsgid(low2highgid(gid));
/* avoid REGPARM breakage on x86: */
prevent_tail_call(ret);
return ret;
}
static int groups16_to_user(old_gid_t __user *grouplist,
struct group_info *group_info)
{
int i;
old_gid_t group;
for (i = 0; i < group_info->ngroups; i++) {
group = high2lowgid(GROUP_AT(group_info, i));
if (put_user(group, grouplist+i))
return -EFAULT;
}
return 0;
}
static int groups16_from_user(struct group_info *group_info,
old_gid_t __user *grouplist)
{
int i;
old_gid_t group;
for (i = 0; i < group_info->ngroups; i++) {
if (get_user(group, grouplist+i))
return -EFAULT;
GROUP_AT(group_info, i) = low2highgid(group);
}
return 0;
}
asmlinkage long sys_getgroups16(int gidsetsize, old_gid_t __user *grouplist)
{
int i = 0;
if (gidsetsize < 0)
return -EINVAL;
get_group_info(current->group_info);
i = current->group_info->ngroups;
if (gidsetsize) {
if (i > gidsetsize) {
i = -EINVAL;
goto out;
}
if (groups16_to_user(grouplist, current->group_info)) {
i = -EFAULT;
goto out;
}
}
out:
put_group_info(current->group_info);
return i;
}
asmlinkage long sys_setgroups16(int gidsetsize, old_gid_t __user *grouplist)
{
struct group_info *group_info;
int retval;
if (!capable(CAP_SETGID))
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
group_info = groups_alloc(gidsetsize);
if (!group_info)
return -ENOMEM;
retval = groups16_from_user(group_info, grouplist);
if (retval) {
put_group_info(group_info);
return retval;
}
retval = set_current_groups(group_info);
put_group_info(group_info);
return retval;
}
asmlinkage long sys_getuid16(void)
{
return high2lowuid(current->uid);
}
asmlinkage long sys_geteuid16(void)
{
return high2lowuid(current->euid);
}
asmlinkage long sys_getgid16(void)
{
return high2lowgid(current->gid);
}
asmlinkage long sys_getegid16(void)
{
return high2lowgid(current->egid);
}