signal: Ensure every siginfo we send has all bits initialized

Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.

Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.

The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.

In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.

Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c
index 33cd35bf3dc8..03e522274b8b 100644
--- a/arch/sparc/kernel/traps_32.c
+++ b/arch/sparc/kernel/traps_32.c
@@ -104,6 +104,7 @@ void do_hw_interrupt(struct pt_regs *regs, unsigned long type)
 	if(regs->psr & PSR_PS)
 		die_if_kernel("Kernel bad trap", regs);
 
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_ILLTRP;
@@ -124,6 +125,7 @@ void do_illegal_instruction(struct pt_regs *regs, unsigned long pc, unsigned lon
 	       regs->pc, *(unsigned long *)regs->pc);
 #endif
 
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_ILLOPC;
@@ -139,6 +141,7 @@ void do_priv_instruction(struct pt_regs *regs, unsigned long pc, unsigned long n
 
 	if(psr & PSR_PS)
 		die_if_kernel("Penguin instruction from Penguin mode??!?!", regs);
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_PRVOPC;
@@ -165,6 +168,7 @@ void do_memaccess_unaligned(struct pt_regs *regs, unsigned long pc, unsigned lon
 	instruction_dump ((unsigned long *) regs->pc);
 	printk ("do_MNA!\n");
 #endif
+	clear_siginfo(&info);
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_ADRALN;
@@ -303,6 +307,7 @@ void do_fpe_trap(struct pt_regs *regs, unsigned long pc, unsigned long npc,
 	}
 
 	fsr = fpt->thread.fsr;
+	clear_siginfo(&info);
 	info.si_signo = SIGFPE;
 	info.si_errno = 0;
 	info.si_addr = (void __user *)pc;
@@ -336,6 +341,7 @@ void handle_tag_overflow(struct pt_regs *regs, unsigned long pc, unsigned long n
 
 	if(psr & PSR_PS)
 		die_if_kernel("Penguin overflow trap from kernel mode", regs);
+	clear_siginfo(&info);
 	info.si_signo = SIGEMT;
 	info.si_errno = 0;
 	info.si_code = EMT_TAGOVF;
@@ -365,6 +371,7 @@ void handle_reg_access(struct pt_regs *regs, unsigned long pc, unsigned long npc
 	printk("Register Access Exception at PC %08lx NPC %08lx PSR %08lx\n",
 	       pc, npc, psr);
 #endif
+	clear_siginfo(&info);
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_OBJERR;
@@ -378,6 +385,7 @@ void handle_cp_disabled(struct pt_regs *regs, unsigned long pc, unsigned long np
 {
 	siginfo_t info;
 
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_COPROC;
@@ -395,6 +403,7 @@ void handle_cp_exception(struct pt_regs *regs, unsigned long pc, unsigned long n
 	printk("Co-Processor Exception at PC %08lx NPC %08lx PSR %08lx\n",
 	       pc, npc, psr);
 #endif
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_COPROC;
@@ -408,6 +417,7 @@ void handle_hw_divzero(struct pt_regs *regs, unsigned long pc, unsigned long npc
 {
 	siginfo_t info;
 
+	clear_siginfo(&info);
 	info.si_signo = SIGFPE;
 	info.si_errno = 0;
 	info.si_code = FPE_INTDIV;