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
  ...

6 files changed, 43 insertions, 174 deletions

diff --git a/arch/tile/include/asm/compat.h b/arch/tile/include/asm/compat.h
index 62a7b83025dd..769ff6ac0bf5 100644
--- a/arch/tile/include/asm/compat.h
+++ b/arch/tile/include/asm/compat.h
@@ -110,68 +110,6 @@ struct compat_flock64 {
 
 typedef u32               compat_sigset_word;
 
-typedef union compat_sigval {
-	compat_int_t	sival_int;
-	compat_uptr_t	sival_ptr;
-} compat_sigval_t;
-
-#define COMPAT_SI_PAD_SIZE	(128/sizeof(int) - 3)
-
-typedef struct compat_siginfo {
-	int si_signo;
-	int si_errno;
-	int si_code;
-
-	union {
-		int _pad[COMPAT_SI_PAD_SIZE];
-
-		/* kill() */
-		struct {
-			unsigned int _pid;	/* sender's pid */
-			unsigned int _uid;	/* sender's uid */
-		} _kill;
-
-		/* POSIX.1b timers */
-		struct {
-			compat_timer_t _tid;	/* timer id */
-			int _overrun;		/* overrun count */
-			compat_sigval_t _sigval;	/* same as below */
-			int _sys_private;	/* not to be passed to user */
-			int _overrun_incr;	/* amount to add to overrun */
-		} _timer;
-
-		/* POSIX.1b signals */
-		struct {
-			unsigned int _pid;	/* sender's pid */
-			unsigned int _uid;	/* sender's uid */
-			compat_sigval_t _sigval;
-		} _rt;
-
-		/* SIGCHLD */
-		struct {
-			unsigned int _pid;	/* which child */
-			unsigned int _uid;	/* sender's uid */
-			int _status;		/* exit code */
-			compat_clock_t _utime;
-			compat_clock_t _stime;
-		} _sigchld;
-
-		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
-		struct {
-			unsigned int _addr;	/* faulting insn/memory ref. */
-#ifdef __ARCH_SI_TRAPNO
-			int _trapno;	/* TRAP # which caused the signal */
-#endif
-		} _sigfault;
-
-		/* SIGPOLL */
-		struct {
-			int _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
-			int _fd;
-		} _sigpoll;
-	} _sifields;
-} compat_siginfo_t;
-
 #define COMPAT_OFF_T_MAX	0x7fffffff
 
 struct compat_ipc64_perm {
diff --git a/arch/tile/include/uapi/asm/siginfo.h b/arch/tile/include/uapi/asm/siginfo.h
index f234d24fff55..a812fcbf4267 100644
--- a/arch/tile/include/uapi/asm/siginfo.h
+++ b/arch/tile/include/uapi/asm/siginfo.h
@@ -24,12 +24,4 @@
 
 #include <asm-generic/siginfo.h>
 
-/*
- * Additional Tile-specific SIGILL si_codes
- */
-#define ILL_DBLFLT	9	/* double fault */
-#define ILL_HARDWALL	10	/* user networks hardwall violation */
-#undef NSIGILL
-#define NSIGILL		10
-
 #endif /* _ASM_TILE_SIGINFO_H */
diff --git a/arch/tile/kernel/compat_signal.c b/arch/tile/kernel/compat_signal.c
index 971d87a1d8cf..a703bd0e0488 100644
--- a/arch/tile/kernel/compat_signal.c
+++ b/arch/tile/kernel/compat_signal.c
@@ -50,79 +50,6 @@ struct compat_rt_sigframe {
 	struct compat_ucontext uc;
 };
 
-int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *from)
-{
-	int err;
-
-	if (!access_ok(VERIFY_WRITE, to, sizeof(struct compat_siginfo)))
-		return -EFAULT;
-
-	/* If you change siginfo_t structure, please make sure that
-	   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.  */
-	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 |= __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);
-	} else {
-		/*
-		 * First 32bits of unions are always present:
-		 * si_pid === si_band === si_tid === si_addr(LS half)
-		 */
-		err |= __put_user(from->_sifields._pad[0],
-				  &to->_sifields._pad[0]);
-		switch (siginfo_layout(from->si_signo, from->si_code)) {
-		case SIL_FAULT:
-			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);
-			/* FALL THROUGH */
-		default:
-		case SIL_KILL:
-			err |= __put_user(from->si_uid, &to->si_uid);
-			break;
-		case SIL_POLL:
-			err |= __put_user(from->si_fd, &to->si_fd);
-			break;
-		case SIL_TIMER:
-			err |= __put_user(from->si_overrun, &to->si_overrun);
-			err |= __put_user(from->si_int, &to->si_int);
-			break;
-		case SIL_RT:
-			err |= __put_user(from->si_uid, &to->si_uid);
-			err |= __put_user(from->si_int, &to->si_int);
-			break;
-		}
-	}
-	return err;
-}
-
-int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
-{
-	int err;
-
-	if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
-		return -EFAULT;
-
-	err = __get_user(to->si_signo, &from->si_signo);
-	err |= __get_user(to->si_errno, &from->si_errno);
-	err |= __get_user(to->si_code, &from->si_code);
-
-	err |= __get_user(to->si_pid, &from->si_pid);
-	err |= __get_user(to->si_uid, &from->si_uid);
-	err |= __get_user(to->si_int, &from->si_int);
-
-	return err;
-}
-
 /* The assembly shim for this function arranges to ignore the return value. */
 long compat_sys_rt_sigreturn(void)
 {
diff --git a/arch/tile/kernel/single_step.c b/arch/tile/kernel/single_step.c
index de3eae813e52..479d8033a801 100644
--- a/arch/tile/kernel/single_step.c
+++ b/arch/tile/kernel/single_step.c
@@ -163,11 +163,13 @@ static tilepro_bundle_bits rewrite_load_store_unaligned(
 	 * actual bad address in an SPR, which it doesn't.
 	 */
 	if (align_ctl == 0) {
-		siginfo_t info = {
-			.si_signo = SIGBUS,
-			.si_code = BUS_ADRALN,
-			.si_addr = addr
-		};
+		siginfo_t info;
+
+		clear_siginfo(&info);
+		info.si_signo = SIGBUS;
+		info.si_code = BUS_ADRALN;
+		info.si_addr = addr;
+
 		trace_unhandled_signal("unaligned trap", regs,
 				       (unsigned long)addr, SIGBUS);
 		force_sig_info(info.si_signo, &info, current);
@@ -210,11 +212,13 @@ static tilepro_bundle_bits rewrite_load_store_unaligned(
 	}
 
 	if (err) {
-		siginfo_t info = {
-			.si_signo = SIGBUS,
-			.si_code = BUS_ADRALN,
-			.si_addr = addr
-		};
+		siginfo_t info;
+
+		clear_siginfo(&info);
+		info.si_signo = SIGBUS;
+		info.si_code = BUS_ADRALN;
+		info.si_addr = addr;
+
 		trace_unhandled_signal("bad address for unaligned fixup", regs,
 				       (unsigned long)addr, SIGBUS);
 		force_sig_info(info.si_signo, &info, current);
diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index 9b08c6055f15..83a7186198d7 100644
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -256,12 +256,14 @@ static int do_bpt(struct pt_regs *regs)
 void __kprobes do_trap(struct pt_regs *regs, int fault_num,
 		       unsigned long reason)
 {
-	siginfo_t info = { 0 };
+	siginfo_t info;
 	int signo, code;
 	unsigned long address = 0;
 	tile_bundle_bits instr;
 	int is_kernel = !user_mode(regs);
 
+	clear_siginfo(&info);
+
 	/* Handle breakpoints, etc. */
 	if (is_kernel && fault_num == INT_ILL && do_bpt(regs))
 		return;
diff --git a/arch/tile/kernel/unaligned.c b/arch/tile/kernel/unaligned.c
index 8149c38f67b6..77a0b6b6a2a1 100644
--- a/arch/tile/kernel/unaligned.c
+++ b/arch/tile/kernel/unaligned.c
@@ -980,11 +980,13 @@ void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
 	}
 
 	if ((align_ctl == 0) || unexpected) {
-		siginfo_t info = {
-			.si_signo = SIGBUS,
-			.si_code = BUS_ADRALN,
-			.si_addr = (unsigned char __user *)0
-		};
+		siginfo_t info;
+
+		clear_siginfo(&info);
+		info.si_signo = SIGBUS;
+		info.si_code = BUS_ADRALN;
+		info.si_addr = (unsigned char __user *)0;
+
 		if (unaligned_printk)
 			pr_info("Unalign bundle: unexp @%llx, %llx\n",
 				(unsigned long long)regs->pc,
@@ -1396,11 +1398,12 @@ void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
 				      &frag, sizeof(frag));
 		if (status) {
 			/* Fail to copy JIT into user land. send SIGSEGV. */
-			siginfo_t info = {
-				.si_signo = SIGSEGV,
-				.si_code = SEGV_MAPERR,
-				.si_addr = (void __user *)&jit_code_area[idx]
-			};
+			siginfo_t info;
+
+			clear_siginfo(&info);
+			info.si_signo = SIGSEGV;
+			info.si_code = SEGV_MAPERR;
+			info.si_addr = (void __user *)&jit_code_area[idx];
 
 			pr_warn("Unalign fixup: pid=%d %s jit_code_area=%llx\n",
 				current->pid, current->comm,
@@ -1511,11 +1514,12 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 	 * If so, we will trigger SIGBUS.
 	 */
 	if ((regs->sp & 0x7) || (regs->ex1) || (align_ctl < 0)) {
-		siginfo_t info = {
-			.si_signo = SIGBUS,
-			.si_code = BUS_ADRALN,
-			.si_addr = (unsigned char __user *)0
-		};
+		siginfo_t info;
+
+		clear_siginfo(&info);
+		info.si_signo = SIGBUS;
+		info.si_code = BUS_ADRALN;
+		info.si_addr = (unsigned char __user *)0;
 
 		if (unaligned_printk)
 			pr_info("Unalign fixup: %d %llx @%llx\n",
@@ -1535,11 +1539,13 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
 	pc = (tilegx_bundle_bits __user *)(regs->pc);
 	if (get_user(bundle, pc) != 0) {
 		/* Probably never be here since pc is valid user address.*/
-		siginfo_t info = {
-			.si_signo = SIGSEGV,
-			.si_code = SEGV_MAPERR,
-			.si_addr = (void __user *)pc
-		};
+		siginfo_t info;
+
+		clear_siginfo(&info);
+		info.si_signo = SIGSEGV;
+		info.si_code = SEGV_MAPERR;
+		info.si_addr = (void __user *)pc;
+
 		pr_err("Couldn't read instruction at %p trying to step\n", pc);
 		trace_unhandled_signal("segfault in unalign fixup", regs,
 				       (unsigned long)info.si_addr, SIGSEGV);