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

Pull force_sig() argument change from Eric Biederman:
 "A source of error over the years has been that force_sig has taken a
  task parameter when it is only safe to use force_sig with the current
  task.

  The force_sig function is built for delivering synchronous signals
  such as SIGSEGV where the userspace application caused a synchronous
  fault (such as a page fault) and the kernel responded with a signal.

  Because the name force_sig does not make this clear, and because the
  force_sig takes a task parameter the function force_sig has been
  abused for sending other kinds of signals over the years. Slowly those
  have been fixed when the oopses have been tracked down.

  This set of changes fixes the remaining abusers of force_sig and
  carefully rips out the task parameter from force_sig and friends
  making this kind of error almost impossible in the future"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
  signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
  signal: Remove the signal number and task parameters from force_sig_info
  signal: Factor force_sig_info_to_task out of force_sig_info
  signal: Generate the siginfo in force_sig
  signal: Move the computation of force into send_signal and correct it.
  signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
  signal: Remove the task parameter from force_sig_fault
  signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
  signal: Explicitly call force_sig_fault on current
  signal/unicore32: Remove tsk parameter from __do_user_fault
  signal/arm: Remove tsk parameter from __do_user_fault
  signal/arm: Remove tsk parameter from ptrace_break
  signal/nds32: Remove tsk parameter from send_sigtrap
  signal/riscv: Remove tsk parameter from do_trap
  signal/sh: Remove tsk parameter from force_sig_info_fault
  signal/um: Remove task parameter from send_sigtrap
  signal/x86: Remove task parameter from send_sigtrap
  signal: Remove task parameter from force_sig_mceerr
  signal: Remove task parameter from force_sig
  signal: Remove task parameter from force_sigsegv
  ...

12 files changed, 26 insertions, 28 deletions

diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index 07003f3f1bfc..e7c596dea947 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -110,7 +110,7 @@ static bool write_ok_or_segv(unsigned long ptr, size_t size)
 		thread->cr2		= ptr;
 		thread->trap_nr		= X86_TRAP_PF;
 
-		force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)ptr, current);
+		force_sig_fault(SIGSEGV, SEGV_MAPERR, (void __user *)ptr);
 		return false;
 	} else {
 		return true;
@@ -289,7 +289,7 @@ do_ret:
 	return true;
 
 sigsegv:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return true;
 }
 
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index 3703c91f441e..78cf265c5b58 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -102,8 +102,7 @@ extern unsigned long profile_pc(struct pt_regs *regs);
 
 extern unsigned long
 convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
-extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
-			 int error_code, int si_code);
+extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code);
 
 
 static inline unsigned long regs_return_value(struct pt_regs *regs)
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index 066562a1ea20..743370ee4983 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1348,7 +1348,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
 		local_irq_enable();
 
 		if (kill_it || do_memory_failure(&m))
-			force_sig(SIGBUS, current);
+			force_sig(SIGBUS);
 		local_irq_disable();
 		ist_end_non_atomic();
 	} else {
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 8eb1e58de043..71691a8310e7 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -1321,18 +1321,19 @@ const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 #endif
 }
 
-void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
-					 int error_code, int si_code)
+void send_sigtrap(struct pt_regs *regs, int error_code, int si_code)
 {
+	struct task_struct *tsk = current;
+
 	tsk->thread.trap_nr = X86_TRAP_DB;
 	tsk->thread.error_code = error_code;
 
 	/* Send us the fake SIGTRAP */
 	force_sig_fault(SIGTRAP, si_code,
-			user_mode(regs) ? (void __user *)regs->ip : NULL, tsk);
+			user_mode(regs) ? (void __user *)regs->ip : NULL);
 }
 
 void user_single_step_report(struct pt_regs *regs)
 {
-	send_sigtrap(current, regs, 0, TRAP_BRKPT);
+	send_sigtrap(regs, 0, TRAP_BRKPT);
 }
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 364813cea647..7cf508f78c8c 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -857,7 +857,7 @@ void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
 		pr_cont("\n");
 	}
 
-	force_sig(SIGSEGV, me);
+	force_sig(SIGSEGV);
 }
 
 #ifdef CONFIG_X86_X32_ABI
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 8b6d03e55d2f..87095a477154 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -254,9 +254,9 @@ do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
 	show_signal(tsk, signr, "trap ", str, regs, error_code);
 
 	if (!sicode)
-		force_sig(signr, tsk);
+		force_sig(signr);
 	else
-		force_sig_fault(signr, sicode, addr, tsk);
+		force_sig_fault(signr, sicode, addr);
 }
 NOKPROBE_SYMBOL(do_trap);
 
@@ -566,7 +566,7 @@ do_general_protection(struct pt_regs *regs, long error_code)
 
 	show_signal(tsk, SIGSEGV, "", desc, regs, error_code);
 
-	force_sig(SIGSEGV, tsk);
+	force_sig(SIGSEGV);
 }
 NOKPROBE_SYMBOL(do_general_protection);
 
@@ -805,7 +805,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
 	}
 	si_code = get_si_code(tsk->thread.debugreg6);
 	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp)
-		send_sigtrap(tsk, regs, error_code, si_code);
+		send_sigtrap(regs, error_code, si_code);
 	cond_local_irq_disable(regs);
 	debug_stack_usage_dec();
 
@@ -856,7 +856,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 		return;
 
 	force_sig_fault(SIGFPE, si_code,
-			(void __user *)uprobe_get_trap_addr(regs), task);
+			(void __user *)uprobe_get_trap_addr(regs));
 }
 
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c
index f8f3cfda01ae..5b345add550f 100644
--- a/arch/x86/kernel/umip.c
+++ b/arch/x86/kernel/umip.c
@@ -277,7 +277,7 @@ static void force_sig_info_umip_fault(void __user *addr, struct pt_regs *regs)
 	tsk->thread.error_code	= X86_PF_USER | X86_PF_WRITE;
 	tsk->thread.trap_nr	= X86_TRAP_PF;
 
-	force_sig_fault(SIGSEGV, SEGV_MAPERR, addr, tsk);
+	force_sig_fault(SIGSEGV, SEGV_MAPERR, addr);
 
 	if (!(show_unhandled_signals && unhandled_signal(tsk, SIGSEGV)))
 		return;
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 918b5092a85f..d8359ebeea70 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -1074,7 +1074,7 @@ arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs
 		pr_err("return address clobbered: pid=%d, %%sp=%#lx, %%ip=%#lx\n",
 		       current->pid, regs->sp, regs->ip);
 
-		force_sig(SIGSEGV, current);
+		force_sig(SIGSEGV);
 	}
 
 	return -1;
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 6a38717d179c..a76c12b38e92 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -583,7 +583,7 @@ int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno)
 		return 1; /* we let this handle by the calling routine */
 	current->thread.trap_nr = trapno;
 	current->thread.error_code = error_code;
-	force_sig(SIGTRAP, current);
+	force_sig(SIGTRAP);
 	return 0;
 }
 
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 58e4f1f00bbc..794f364cb882 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -760,8 +760,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 			set_signal_archinfo(address, error_code);
 
 			/* XXX: hwpoison faults will set the wrong code. */
-			force_sig_fault(signal, si_code, (void __user *)address,
-					tsk);
+			force_sig_fault(signal, si_code, (void __user *)address);
 		}
 
 		/*
@@ -922,7 +921,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
 		if (si_code == SEGV_PKUERR)
 			force_sig_pkuerr((void __user *)address, pkey);
 
-		force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk);
+		force_sig_fault(SIGSEGV, si_code, (void __user *)address);
 
 		return;
 	}
@@ -1019,8 +1018,6 @@ static void
 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 	  vm_fault_t fault)
 {
-	struct task_struct *tsk = current;
-
 	/* Kernel mode? Handle exceptions or die: */
 	if (!(error_code & X86_PF_USER)) {
 		no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
@@ -1035,6 +1032,7 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 
 #ifdef CONFIG_MEMORY_FAILURE
 	if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
+		struct task_struct *tsk = current;
 		unsigned lsb = 0;
 
 		pr_err(
@@ -1044,11 +1042,11 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 			lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
 		if (fault & VM_FAULT_HWPOISON)
 			lsb = PAGE_SHIFT;
-		force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, tsk);
+		force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb);
 		return;
 	}
 #endif
-	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk);
+	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
 }
 
 static noinline void
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 0d1c47cbbdd6..895fb7a9294d 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -912,7 +912,7 @@ void mpx_notify_unmap(struct mm_struct *mm, unsigned long start,
 
 	ret = mpx_unmap_tables(mm, start, end);
 	if (ret)
-		force_sig(SIGSEGV, current);
+		force_sig(SIGSEGV);
 }
 
 /* MPX cannot handle addresses above 47 bits yet. */
diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c
index 8b4a71efe7ee..7c11c9e5d7ea 100644
--- a/arch/x86/um/signal.c
+++ b/arch/x86/um/signal.c
@@ -471,7 +471,7 @@ long sys_sigreturn(void)
 	return PT_REGS_SYSCALL_RET(&current->thread.regs);
 
  segfault:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return 0;
 }
 
@@ -577,6 +577,6 @@ long sys_rt_sigreturn(void)
 	return PT_REGS_SYSCALL_RET(&current->thread.regs);
 
  segfault:
-	force_sig(SIGSEGV, current);
+	force_sig(SIGSEGV);
 	return 0;
 }