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signal: replace sigset_to_compat() with put_compat_sigset()

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There are 4 callers of sigset_to_compat() in the entire kernel.  One is
in sparc compat rt_sigaction(2), the rest are in kernel/signal.c itself.
All are followed by copy_to_user(), and all but the sparc one are under
"if it's big-endian..." ifdefs.

Let's transform sigset_to_compat() into put_compat_sigset() that also
calls copy_to_user().

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Dmitry V. Levin 2017-08-22 02:16:11 +03:00 committed by Al Viro
parent 2bd6bf03f4
commit f454322efb
4 changed files with 25 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
arch/sparc/kernel/sys_sparc32.c
View file

@ -159,7 +159,6 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig,
{
struct k_sigaction new_ka, old_ka;
int ret;
compat_sigset_t set32;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(compat_sigset_t))
@ -167,6 +166,7 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig,
if (act) {
u32 u_handler, u_restorer;
compat_sigset_t set32;
new_ka.ka_restorer = restorer;
ret = get_user(u_handler, &act->sa_handler);
@ -183,9 +183,9 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig,
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
sigset_to_compat(&set32, &old_ka.sa.sa_mask);
ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler);
ret |= copy_to_user(&oact->sa_mask, &set32, sizeof(compat_sigset_t));
ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
sizeof(oact->sa_mask));
ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer);
if (ret)

3
include/linux/compat.h
View file

@ -456,7 +456,8 @@ asmlinkage long compat_sys_settimeofday(struct compat_timeval __user *tv,
asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
extern void sigset_from_compat(sigset_t *set, const compat_sigset_t *compat);
extern void sigset_to_compat(compat_sigset_t *compat, const sigset_t *set);
extern int put_compat_sigset(compat_sigset_t __user *compat,
const sigset_t *set, unsigned int size);
asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,

20
kernel/compat.c
View file

@ -497,15 +497,23 @@ sigset_from_compat(sigset_t *set, const compat_sigset_t *compat)
}
EXPORT_SYMBOL_GPL(sigset_from_compat);
void
sigset_to_compat(compat_sigset_t *compat, const sigset_t *set)
int
put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set,
unsigned int size)
{
/* size <= sizeof(compat_sigset_t) <= sizeof(sigset_t) */
#ifdef __BIG_ENDIAN
compat_sigset_t v;
switch (_NSIG_WORDS) {
case 4: compat->sig[7] = (set->sig[3] >> 32); compat->sig[6] = set->sig[3];
case 3: compat->sig[5] = (set->sig[2] >> 32); compat->sig[4] = set->sig[2];
case 2: compat->sig[3] = (set->sig[1] >> 32); compat->sig[2] = set->sig[1];
case 1: compat->sig[1] = (set->sig[0] >> 32); compat->sig[0] = set->sig[0];
case 4: v.sig[7] = (set->sig[3] >> 32); v.sig[6] = set->sig[3];
case 3: v.sig[5] = (set->sig[2] >> 32); v.sig[4] = set->sig[2];
case 2: v.sig[3] = (set->sig[1] >> 32); v.sig[2] = set->sig[1];
case 1: v.sig[1] = (set->sig[0] >> 32); v.sig[0] = set->sig[0];
}
return copy_to_user(compat, &v, size) ? -EFAULT : 0;
#else
return copy_to_user(compat, set, size) ? -EFAULT : 0;
#endif
}
#ifdef CONFIG_NUMA

27
kernel/signal.c
View file

@ -2621,13 +2621,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
if (error)
return error;
}
if (oset) {
compat_sigset_t old32;
sigset_to_compat(&old32, &old_set);
if (copy_to_user(oset, &old32, sizeof(compat_sigset_t)))
return -EFAULT;
}
return 0;
return oset ? put_compat_sigset(oset, &old_set, sizeof(*oset)) : 0;
#else
return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
(sigset_t __user *)oset, sigsetsize);
@ -2669,20 +2663,11 @@ SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, uset, size_t, sigsetsize)
COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
compat_size_t, sigsetsize)
{
#ifdef __BIG_ENDIAN
sigset_t set;
int err = do_sigpending(&set, sigsetsize);
if (!err) {
compat_sigset_t set32;
sigset_to_compat(&set32, &set);
/* we can get here only if sigsetsize <= sizeof(set) */
if (copy_to_user(uset, &set32, sigsetsize))
err = -EFAULT;
}
if (!err)
err = put_compat_sigset(uset, &set, sigsetsize);
return err;
#else
return sys_rt_sigpending((sigset_t __user *)uset, sigsetsize);
#endif
}
#endif
@ -3451,7 +3436,6 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
compat_size_t, sigsetsize)
{
struct k_sigaction new_ka, old_ka;
compat_sigset_t mask;
#ifdef __ARCH_HAS_SA_RESTORER
compat_uptr_t restorer;
#endif
@ -3463,6 +3447,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
if (act) {
compat_uptr_t handler;
compat_sigset_t mask;
ret = get_user(handler, &act->sa_handler);
new_ka.sa.sa_handler = compat_ptr(handler);
#ifdef __ARCH_HAS_SA_RESTORER
@ -3478,10 +3463,10 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
sigset_to_compat(&mask, &old_ka.sa.sa_mask);
ret = put_user(ptr_to_compat(old_ka.sa.sa_handler),
&oact->sa_handler);
ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
ret |= put_compat_sigset(&oact->sa_mask, &old_ka.sa.sa_mask,
sizeof(oact->sa_mask));
ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
#ifdef __ARCH_HAS_SA_RESTORER
ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),