Commit d4173023 authored Jan 30, 2018 by Linus Torvalds

Merge branch 'siginfo-linus' of...

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
...

parents 0aebc6a4 c0f45555

arch/arc/kernel/traps.c

+8 −6

Original line number	Diff line number	Diff line
		@@ -65,12 +65,14 @@ unhandled_exception(const char str, struct pt_regs regs, siginfo_t *info)
		#define DO_ERROR_INFO(signr, str, name, sicode) \
		int name(unsigned long address, struct pt_regs *regs) \
		{ \
		siginfo_t info = { \
		.si_signo = signr, \
		.si_errno = 0, \
		.si_code = sicode, \
		.si_addr = (void __user *)address, \
		}; \
		siginfo_t info; \
		\
		clear_siginfo(&info); \
		info.si_signo = signr; \
		info.si_errno = 0; \
		info.si_code = sicode; \
		info.si_addr = (void __user *)address; \
		\
		return unhandled_exception(str, regs, &info);\
		}

arch/arm/include/uapi/asm/siginfo.h

0 → 100644

+13 −0

Original line number	Diff line number	Diff line
		#ifndef __ASM_SIGINFO_H
		#define __ASM_SIGINFO_H

		#include <asm-generic/siginfo.h>

		/*
		* SIGFPE si_codes
		*/
		#ifdef __KERNEL__
		#define FPE_FIXME 0 /* Broken dup of SI_USER */
		#endif /* __KERNEL__ */

		#endif

arch/arm/kernel/ptrace.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -390,7 +390,6 @@ static void ptrace_hbptriggered(struct perf_event *bp,
		struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
		long num;
		int i;
		siginfo_t info;

		for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
		if (current->thread.debug.hbp[i] == bp)
		@@ -398,12 +397,7 @@ static void ptrace_hbptriggered(struct perf_event *bp,

		num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);

		info.si_signo = SIGTRAP;
		info.si_errno = (int)num;
		info.si_code = TRAP_HWBKPT;
		info.si_addr = (void __user *)(bkpt->trigger);

		force_sig_info(SIGTRAP, &info, current);
		force_sig_ptrace_errno_trap((int)num, (void __user *)(bkpt->trigger));
		}

		/*

arch/arm/vfp/vfpmodule.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -257,7 +257,7 @@ static void vfp_raise_exceptions(u32 exceptions, u32 inst, u32 fpscr, struct pt_

		if (exceptions == VFP_EXCEPTION_ERROR) {
		vfp_panic("unhandled bounce", inst);
		vfp_raise_sigfpe(0, regs);
		vfp_raise_sigfpe(FPE_FIXME, regs);
		return;
		}

arch/arm64/include/asm/compat.h

+0 −64

Original line number	Diff line number	Diff line
		@@ -150,70 +150,6 @@ typedef u32 compat_old_sigset_t;

		typedef u32 compat_sigset_word;

		typedef union compat_sigval {
		compat_int_t sival_int;
		compat_uptr_t sival_ptr;
		} compat_sigval_t;

		typedef struct compat_siginfo {
		int si_signo;
		int si_errno;
		int si_code;

		union {
		int _pad[128/sizeof(int) - 3];

		/* kill() */
		struct {
		compat_pid_t _pid; /* sender's pid */
		__compat_uid32_t _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 */
		} _timer;

		/* POSIX.1b signals */
		struct {
		compat_pid_t _pid; /* sender's pid */
		__compat_uid32_t _uid; /* sender's uid */
		compat_sigval_t _sigval;
		} _rt;

		/* SIGCHLD */
		struct {
		compat_pid_t _pid; /* which child */
		__compat_uid32_t _uid; /* sender's uid */
		int _status; /* exit code */
		compat_clock_t _utime;
		compat_clock_t _stime;
		} _sigchld;

		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
		struct {
		compat_uptr_t _addr; /* faulting insn/memory ref. */
		short _addr_lsb; /* LSB of the reported address */
		} _sigfault;

		/* SIGPOLL */
		struct {
		compat_long_t _band; /* POLL_IN, POLL_OUT, POLL_MSG */
		int _fd;
		} _sigpoll;

		/* SIGSYS */
		struct {
		compat_uptr_t _call_addr; /* calling user insn */
		int _syscall; /* triggering system call number */
		compat_uint_t _arch; /* AUDIT_ARCH_* of syscall */
		} _sigsys;
		} _sifields;
		} compat_siginfo_t;

		#define COMPAT_OFF_T_MAX 0x7fffffff

		/*