[PATCH 3/8] signal: replace __copy_siginfo_to_user32 with to_compat_siginfo

Christoph Hellwig hch at lst.de
Tue Apr 14 17:01:37 AEST 2020


Move copying the siginfo to userspace into the callers, so that the
compat_siginfo conversion can be reused by the ELF coredump code without
set_fs magic.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 arch/x86/ia32/ia32_signal.c |  4 +-
 arch/x86/kernel/signal.c    |  5 ++-
 include/linux/compat.h      |  4 +-
 kernel/signal.c             | 89 ++++++++++++++++++-------------------
 4 files changed, 52 insertions(+), 50 deletions(-)

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 2bf188942d5c..0fbaed2562bc 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -301,6 +301,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 			compat_sigset_t *set, struct pt_regs *regs)
 {
 	struct rt_sigframe_ia32 __user *frame;
+	struct compat_siginfo new;
 	void __user *restorer;
 	void __user *fp = NULL;
 
@@ -350,7 +351,8 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
 	unsafe_put_user(*(__u64 *)set, (__u64 *)&frame->uc.uc_sigmask, Efault);
 	user_access_end();
 
-	if (__copy_siginfo_to_user32(&frame->info, &ksig->info, SA_IA32_ABI))
+	to_compat_siginfo(&new, &ksig->info, SA_IA32_ABI);
+	if (copy_to_user(&frame->info, &new, sizeof(frame->info)))
 		return -EFAULT;
 
 	/* Set up registers for signal handler */
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index bbd451631790..6ff1265f071b 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -517,6 +517,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
 {
 #ifdef CONFIG_X86_X32_ABI
 	struct rt_sigframe_x32 __user *frame;
+	struct compat_siginfo new;
 	unsigned long uc_flags;
 	void __user *restorer;
 	void __user *fp = NULL;
@@ -543,8 +544,8 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
 	user_access_end();
 
 	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
-		if (__copy_siginfo_to_user32(&frame->info, &ksig->info,
-				SA_X32_ABI))
+		to_compat_siginfo(&new, &ksig->info, SA_X32_ABI);
+		if (copy_to_user(&frame->info, &new, sizeof(frame->info)))
 			return -EFAULT;
 	}
 
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 14eec6116110..218ebba1e454 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -404,8 +404,8 @@ long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 		       unsigned long bitmap_size);
 int copy_siginfo_from_user32(kernel_siginfo_t *to, const struct compat_siginfo __user *from);
 int copy_siginfo_to_user32(struct compat_siginfo __user *to, const kernel_siginfo_t *from);
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-		const kernel_siginfo_t *from, unsigned int flags);
+void to_compat_siginfo(struct compat_siginfo *to,
+		const struct kernel_siginfo *from, unsigned int flags);
 int get_compat_sigevent(struct sigevent *event,
 		const struct compat_sigevent __user *u_event);
 
diff --git a/kernel/signal.c b/kernel/signal.c
index 092fee008242..0f3e7fded3a5 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3235,88 +3235,82 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 }
 
 #ifdef CONFIG_COMPAT
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
+void to_compat_siginfo(struct compat_siginfo *to,
 		const struct kernel_siginfo *from, unsigned int flags)
 {
-	struct compat_siginfo new;
-	memset(&new, 0, sizeof(new));
+	memset(to, 0, sizeof(*to));
+	to->si_signo = from->si_signo;
+	to->si_errno = from->si_errno;
+	to->si_code  = from->si_code;
 
-	new.si_signo = from->si_signo;
-	new.si_errno = from->si_errno;
-	new.si_code  = from->si_code;
-	switch(siginfo_layout(from->si_signo, from->si_code)) {
+	switch (siginfo_layout(from->si_signo, from->si_code)) {
 	case SIL_KILL:
-		new.si_pid = from->si_pid;
-		new.si_uid = from->si_uid;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
 		break;
 	case SIL_TIMER:
-		new.si_tid     = from->si_tid;
-		new.si_overrun = from->si_overrun;
-		new.si_int     = from->si_int;
+		to->si_tid     = from->si_tid;
+		to->si_overrun = from->si_overrun;
+		to->si_int     = from->si_int;
 		break;
 	case SIL_POLL:
-		new.si_band = from->si_band;
-		new.si_fd   = from->si_fd;
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
 		break;
 	case SIL_FAULT:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
 		break;
 	case SIL_FAULT_MCEERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_addr_lsb = from->si_addr_lsb;
+		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_lower = ptr_to_compat(from->si_lower);
-		new.si_upper = ptr_to_compat(from->si_upper);
+		to->si_lower = ptr_to_compat(from->si_lower);
+		to->si_upper = ptr_to_compat(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_pkey = from->si_pkey;
+		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_CHLD:
-		new.si_pid    = from->si_pid;
-		new.si_uid    = from->si_uid;
-		new.si_status = from->si_status;
+		to->si_pid    = from->si_pid;
+		to->si_uid    = from->si_uid;
+		to->si_status = from->si_status;
 #ifdef CONFIG_X86_X32_ABI
 		if (flags & SA_X32_ABI) {
-			new._sifields._sigchld_x32._utime = from->si_utime;
-			new._sifields._sigchld_x32._stime = from->si_stime;
+			to->_sifields._sigchld_x32._utime = from->si_utime;
+			to->_sifields._sigchld_x32._stime = from->si_stime;
 		} else
 #endif
 		{
-			new.si_utime = from->si_utime;
-			new.si_stime = from->si_stime;
+			to->si_utime = from->si_utime;
+			to->si_stime = from->si_stime;
 		}
 		break;
 	case SIL_RT:
-		new.si_pid = from->si_pid;
-		new.si_uid = from->si_uid;
-		new.si_int = from->si_int;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_int = from->si_int;
 		break;
 	case SIL_SYS:
-		new.si_call_addr = ptr_to_compat(from->si_call_addr);
-		new.si_syscall   = from->si_syscall;
-		new.si_arch      = from->si_arch;
+		to->si_call_addr = ptr_to_compat(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
 		break;
 	}
-
-	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
-		return -EFAULT;
-
-	return 0;
 }
 
 #ifndef compat_siginfo_flags
@@ -3326,7 +3320,12 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
 			   const struct kernel_siginfo *from)
 {
-	return __copy_siginfo_to_user32(to, from, compat_siginfo_flags());
+	struct compat_siginfo new;
+
+	to_compat_siginfo(&new, from, compat_siginfo_flags());
+	if (copy_to_user(to, &new, sizeof(*to)))
+		return -EFAULT;
+	return 0;
 }
 
 static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
-- 
2.25.1



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