Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull siginfo cleanups from Eric Biederman:
 "Long ago when 2.4 was just a testing release copy_siginfo_to_user was
  made to copy individual fields to userspace, possibly for efficiency
  and to ensure initialized values were not copied to userspace.

  Unfortunately the design was complex, it's assumptions unstated, and
  humans are fallible and so while it worked much of the time that
  design failed to ensure unitialized memory is not copied to userspace.

  This set of changes is part of a new design to clean up siginfo and
  simplify things, and hopefully make the siginfo handling robust enough
  that a simple inspection of the code can be made to ensure we don't
  copy any unitializied fields to userspace.

  The design is to unify struct siginfo and struct compat_siginfo into a
  single definition that is shared between all architectures so that
  anyone adding to the set of information shared with struct siginfo can
  see the whole picture. Hopefully ensuring all future si_code
  assignments are arch independent.

  The design is to unify copy_siginfo_to_user32 and
  copy_siginfo_from_user32 so that those function are complete and cope
  with all of the different cases documented in signinfo_layout. I don't
  think there was a single implementation of either of those functions
  that was complete and correct before my changes unified them.

  The design is to introduce a series of helpers including
  force_siginfo_fault that take the values that are needed in struct
  siginfo and build the siginfo structure for their callers. Ensuring
  struct siginfo is built correctly.

  The remaining work for 4.17 (unless someone thinks it is post -rc1
  material) is to push usage of those helpers down into the
  architectures so that architecture specific code will not need to deal
  with the fiddly work of intializing struct siginfo, and then when
  struct siginfo is guaranteed to be fully initialized change copy
  siginfo_to_user into a simple wrapper around copy_to_user.

  Further there is work in progress on the issues that have been
  documented requires arch specific knowledge to sort out.

  The changes below fix or at least document all of the issues that have
  been found with siginfo generation. Then proceed to unify struct
  siginfo the 32 bit helpers that copy siginfo to and from userspace,
  and generally clean up anything that is not arch specific with regards
  to siginfo generation.

  It is a lot but with the unification you can of siginfo you can
  already see the code reduction in the kernel"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (45 commits)
  signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr
  mm/memory_failure: Remove unused trapno from memory_failure
  signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed
  signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap
  signal: Helpers for faults with specialized siginfo layouts
  signal: Add send_sig_fault and force_sig_fault
  signal: Replace memset(info,...) with clear_siginfo for clarity
  signal: Don't use structure initializers for struct siginfo
  signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered
  ptrace: Use copy_siginfo in setsiginfo and getsiginfo
  signal: Unify and correct copy_siginfo_to_user32
  signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32
  signal: Unify and correct copy_siginfo_from_user32
  signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED
  signal/blackfin: Move the blackfin specific si_codes to asm-generic/siginfo.h
  signal/tile: Move the tile specific si_codes to asm-generic/siginfo.h
  signal/frv: Move the frv specific si_codes to asm-generic/siginfo.h
  signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h
  signal/powerpc: Remove redefinition of NSIGTRAP on powerpc
  signal: Move addr_lsb into the _sigfault union for clarity
  ...

2 files changed, 20 insertions, 76 deletions

diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index cf5c7c05..c4db910 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -76,70 +76,3 @@ SYSCALL_DEFINE3(32_sigaction, long, sig, const struct compat_sigaction __user *,
 
 	return ret;
 }
-
-int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
-{
-	int err;
-
-	if (!access_ok (VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
-		return -EFAULT;
-
-	/* If you change siginfo_t structure, please be sure
-	   this code is fixed accordingly.
-	   It should never copy any pad contained in the structure
-	   to avoid security leaks, but must copy the generic
-	   3 ints plus the relevant union member.
-	   This routine must convert siginfo from 64bit to 32bit as well
-	   at the same time.  */
-	err = __put_user(from->si_signo, &to->si_signo);
-	err |= __put_user(from->si_errno, &to->si_errno);
-	err |= __put_user(from->si_code, &to->si_code);
-	if (from->si_code < 0)
-		err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
-	else {
-		switch (siginfo_layout(from->si_signo, from->si_code)) {
-		case SIL_TIMER:
-			err |= __put_user(from->si_tid, &to->si_tid);
-			err |= __put_user(from->si_overrun, &to->si_overrun);
-			err |= __put_user(from->si_int, &to->si_int);
-			break;
-		case SIL_CHLD:
-			err |= __put_user(from->si_utime, &to->si_utime);
-			err |= __put_user(from->si_stime, &to->si_stime);
-			err |= __put_user(from->si_status, &to->si_status);
-		case SIL_KILL:
-			err |= __put_user(from->si_pid, &to->si_pid);
-			err |= __put_user(from->si_uid, &to->si_uid);
-			break;
-		case SIL_FAULT:
-			err |= __put_user((unsigned long)from->si_addr, &to->si_addr);
-			break;
-		case SIL_POLL:
-			err |= __put_user(from->si_band, &to->si_band);
-			err |= __put_user(from->si_fd, &to->si_fd);
-			break;
-		case SIL_RT:
-			err |= __put_user(from->si_pid, &to->si_pid);
-			err |= __put_user(from->si_uid, &to->si_uid);
-			err |= __put_user(from->si_int, &to->si_int);
-			break;
-		case SIL_SYS:
-			err |= __copy_to_user(&to->si_call_addr, &from->si_call_addr,
-					      sizeof(compat_uptr_t));
-			err |= __put_user(from->si_syscall, &to->si_syscall);
-			err |= __put_user(from->si_arch, &to->si_arch);
-			break;
-		}
-	}
-	return err;
-}
-
-int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
-{
-	if (copy_from_user(to, from, 3*sizeof(int)) ||
-	    copy_from_user(to->_sifields._pad,
-			   from->_sifields._pad, SI_PAD_SIZE32))
-		return -EFAULT;
-
-	return 0;
-}
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 5d19ed0..0ae4a73 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -699,11 +699,12 @@ static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
 asmlinkage void do_ov(struct pt_regs *regs)
 {
 	enum ctx_state prev_state;
-	siginfo_t info = {
-		.si_signo = SIGFPE,
-		.si_code = FPE_INTOVF,
-		.si_addr = (void __user *)regs->cp0_epc,
-	};
+	siginfo_t info;
+
+	clear_siginfo(&info);
+	info.si_signo = SIGFPE;
+	info.si_code = FPE_INTOVF;
+	info.si_addr = (void __user *)regs->cp0_epc;
 
 	prev_state = exception_enter();
 	die_if_kernel("Integer overflow", regs);
@@ -721,7 +722,11 @@ asmlinkage void do_ov(struct pt_regs *regs)
 void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
 		     struct task_struct *tsk)
 {
-	struct siginfo si = { .si_addr = fault_addr, .si_signo = SIGFPE };
+	struct siginfo si;
+
+	clear_siginfo(&si);
+	si.si_addr = fault_addr;
+	si.si_signo = SIGFPE;
 
 	if (fcr31 & FPU_CSR_INV_X)
 		si.si_code = FPE_FLTINV;
@@ -739,9 +744,10 @@ void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
 
 int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31)
 {
-	struct siginfo si = { 0 };
+	struct siginfo si;
 	struct vm_area_struct *vma;
 
+	clear_siginfo(&si);
 	switch (sig) {
 	case 0:
 		return 0;
@@ -890,9 +896,10 @@ out:
 void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code,
 	const char *str)
 {
-	siginfo_t info = { 0 };
+	siginfo_t info;
 	char b[40];
 
+	clear_siginfo(&info);
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, current->thread.trap_nr,
 			 SIGTRAP) == NOTIFY_STOP)
@@ -1499,9 +1506,13 @@ asmlinkage void do_mdmx(struct pt_regs *regs)
  */
 asmlinkage void do_watch(struct pt_regs *regs)
 {
-	siginfo_t info = { .si_signo = SIGTRAP, .si_code = TRAP_HWBKPT };
+	siginfo_t info;
 	enum ctx_state prev_state;
 
+	clear_siginfo(&info);
+	info.si_signo = SIGTRAP;
+	info.si_code = TRAP_HWBKPT;
+
 	prev_state = exception_enter();
 	/*
 	 * Clear WP (bit 22) bit of cause register so we don't loop