In the same spirit as commit fb05121fd6a2 ("signal: Add
unsafe_get_compat_sigset()"), implement an 'unsafe' version of
copy_siginfo_to_user() in order to use it within user access blocks.
For that, also add an 'unsafe' version of clear_user().
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
include/linux/signal.h | 15 +++++++++++++++
include/linux/uaccess.h | 1 +
kernel/signal.c | 5 -----
3 files changed, 16 insertions(+), 5 deletions(-)
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 201f88e3738b..beac7b5e4acc 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -35,6 +35,21 @@ static inline void copy_siginfo_to_external(siginfo_t *to,
int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
+static __always_inline char __user *si_expansion(const siginfo_t __user *info)
+{
+ return ((char __user *)info) + sizeof(struct kernel_siginfo);
+}
+
+#define unsafe_copy_siginfo_to_user(to, from, label) do { \
+ siginfo_t __user *__ucs_to = to; \
+ const kernel_siginfo_t *__ucs_from = from; \
+ char __user *__ucs_expansion = si_expansion(__ucs_to); \
+ \
+ unsafe_copy_to_user(__ucs_to, __ucs_from, \
+ sizeof(struct kernel_siginfo), label); \
+ unsafe_clear_user(__ucs_expansion, SI_EXPANSION_SIZE, label); \
+} while (0)
+
enum siginfo_layout {
SIL_KILL,
SIL_TIMER,
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index c05e903cef02..37073caac474 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -398,6 +398,7 @@ long strnlen_user_nofault(const void __user *unsafe_addr, long count);
#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)
+#define unsafe_clear_user(d, l, e) unsafe_op_wrap(__clear_user(d, l), e)
static inline unsigned long user_access_save(void) { return 0UL; }
static inline void user_access_restore(unsigned long flags) { }
#endif
diff --git a/kernel/signal.c b/kernel/signal.c
index f7c6ffcbd044..7a366331d2b7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3286,11 +3286,6 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
return layout;
}
-static inline char __user *si_expansion(const siginfo_t __user *info)
-{
- return ((char __user *)info) + sizeof(struct kernel_siginfo);
-}
-
int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
{
char __user *expansion = si_expansion(to);
--
2.25.0
