Commit 14026b94 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

signal: Add unsafe_put_compat_sigset() 



Implement 'unsafe' version of put_compat_sigset()

For the bigendian, use unsafe_put_user() directly
to avoid intermediate copy through the stack.

For the littleendian, use a straight unsafe_copy_to_user().

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/537c7082ee309a0bb9c67a50c5d9dd929aedb82d.1597770847.git.christophe.leroy@csgroup.eu
parent f1cf4f93

include/linux/compat.h

+32 −0
Original line number Diff line number Diff line
@@ -442,6 +442,38 @@ put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set, 
#endif

}



#ifdef CONFIG_CPU_BIG_ENDIAN

#define unsafe_put_compat_sigset(compat, set, label) do {		\

	compat_sigset_t __user *__c = compat;				\

	const sigset_t *__s = set;					\

									\

	switch (_NSIG_WORDS) {						\

	case 4:								\

		unsafe_put_user(__s->sig[3] >> 32, &__c->sig[7], label);	\

		unsafe_put_user(__s->sig[3], &__c->sig[6], label);	\

		fallthrough;						\

	case 3:								\

		unsafe_put_user(__s->sig[2] >> 32, &__c->sig[5], label);	\

		unsafe_put_user(__s->sig[2], &__c->sig[4], label);	\

		fallthrough;						\

	case 2:								\

		unsafe_put_user(__s->sig[1] >> 32, &__c->sig[3], label);	\

		unsafe_put_user(__s->sig[1], &__c->sig[2], label);	\

		fallthrough;						\

	case 1:								\

		unsafe_put_user(__s->sig[0] >> 32, &__c->sig[1], label);	\

		unsafe_put_user(__s->sig[0], &__c->sig[0], label);	\

	}								\

} while (0)

#else

#define unsafe_put_compat_sigset(compat, set, label) do {		\

	compat_sigset_t __user *__c = compat;				\

	const sigset_t *__s = set;					\

									\

	unsafe_copy_to_user(__c, __s, sizeof(*__c), label);		\

} while (0)

#endif



extern int compat_ptrace_request(struct task_struct *child,

				 compat_long_t request,

				 compat_ulong_t addr, compat_ulong_t data);