In the same way as commit 14026b94ccfe ("signal: Add
unsafe_put_compat_sigset()"), this time add
unsafe_get_compat_sigset() macro which is the 'unsafe'
version of get_compat_sigset()
For the bigendian, use unsafe_get_user() directly
to avoid intermediate copy through the stack.
For the littleendian, use a straight unsafe_copy_from_user().
This commit adds the generic fallback for unsafe_copy_from_user().
Architectures wanting to use unsafe_get_compat_sigset() have to
make sure they have their own unsafe_copy_from_user().
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
include/linux/compat.h | 35 +++++++++++++++++++++++++++++++++++
include/linux/uaccess.h | 1 +
2 files changed, 36 insertions(+)
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 6e65be753603..5112c3e35782 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -465,6 +465,34 @@ put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set,
unsafe_put_user(__s->sig[0], &__c->sig[0], label); \
} \
} while (0)
+
+#define unsafe_get_compat_sigset(set, compat, label) do { \
+ const compat_sigset_t __user *__c = compat; \
+ compat_sigset_word hi, lo; \
+ sigset_t *__s = set; \
+ \
+ switch (_NSIG_WORDS) { \
+ case 4: \
+ unsafe_get_user(lo, &__c->sig[7], label); \
+ unsafe_get_user(hi, &__c->sig[6], label); \
+ __s->sig[3] = hi | (((long)lo) << 32); \
+ fallthrough; \
+ case 3: \
+ unsafe_get_user(lo, &__c->sig[5], label); \
+ unsafe_get_user(hi, &__c->sig[4], label); \
+ __s->sig[2] = hi | (((long)lo) << 32); \
+ fallthrough; \
+ case 2: \
+ unsafe_get_user(lo, &__c->sig[3], label); \
+ unsafe_get_user(hi, &__c->sig[2], label); \
+ __s->sig[1] = hi | (((long)lo) << 32); \
+ fallthrough; \
+ case 1: \
+ unsafe_get_user(lo, &__c->sig[1], label); \
+ unsafe_get_user(hi, &__c->sig[0], label); \
+ __s->sig[0] = hi | (((long)lo) << 32); \
+ } \
+} while (0)
#else
#define unsafe_put_compat_sigset(compat, set, label) do { \
compat_sigset_t __user *__c = compat; \
@@ -472,6 +500,13 @@ put_compat_sigset(compat_sigset_t __user *compat, const sigset_t *set,
\
unsafe_copy_to_user(__c, __s, sizeof(*__c), label); \
} while (0)
+
+#define unsafe_get_compat_sigset(set, compat, label) do { \
+ const compat_sigset_t __user *__c = compat; \
+ sigset_t *__s = set; \
+ \
+ unsafe_copy_from_user(__s, __c, sizeof(*__c), label); \
+} while (0)
#endif
extern int compat_ptrace_request(struct task_struct *child,
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index c7c6e8b8344d..c05e903cef02 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -397,6 +397,7 @@ long strnlen_user_nofault(const void __user *unsafe_addr, long count);
#define unsafe_get_user(x,p,e) unsafe_op_wrap(__get_user(x,p),e)
#define unsafe_put_user(x,p,e) unsafe_op_wrap(__put_user(x,p),e)
#define unsafe_copy_to_user(d,s,l,e) unsafe_op_wrap(__copy_to_user(d,s,l),e)
+#define unsafe_copy_from_user(d,s,l,e) unsafe_op_wrap(__copy_from_user(d,s,l),e)
static inline unsigned long user_access_save(void) { return 0UL; }
static inline void user_access_restore(unsigned long flags) { }
#endif
--
2.25.0
