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, 14 insertions, 0 deletions

diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index e81072ac52c3..b485b49b87a8 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -107,6 +107,7 @@ void bad_trap(struct pt_regs *regs, long lvl)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_ILLTRP;
@@ -206,6 +207,7 @@ void spitfire_insn_access_exception(struct pt_regs *regs, unsigned long sfsr, un
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
 	info.si_errno = 0;
 	info.si_code = SEGV_MAPERR;
@@ -247,6 +249,7 @@ void sun4v_insn_access_exception(struct pt_regs *regs, unsigned long addr, unsig
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
 	info.si_errno = 0;
 	info.si_code = SEGV_MAPERR;
@@ -338,6 +341,7 @@ void spitfire_data_access_exception(struct pt_regs *regs, unsigned long sfsr, un
 	if (is_no_fault_exception(regs))
 		return;
 
+	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
 	info.si_errno = 0;
 	info.si_code = SEGV_MAPERR;
@@ -595,6 +599,7 @@ static void spitfire_ue_log(unsigned long afsr, unsigned long afar, unsigned lon
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_OBJERR;
@@ -2211,6 +2216,7 @@ bool sun4v_nonresum_error_user_handled(struct pt_regs *regs,
 				addr += PAGE_SIZE;
 			}
 		}
+		clear_siginfo(&info);
 		info.si_signo = SIGKILL;
 		info.si_errno = 0;
 		info.si_trapno = 0;
@@ -2221,6 +2227,7 @@ bool sun4v_nonresum_error_user_handled(struct pt_regs *regs,
 	if (attrs & SUN4V_ERR_ATTRS_PIO) {
 		siginfo_t info;
 
+		clear_siginfo(&info);
 		info.si_signo = SIGBUS;
 		info.si_code = BUS_ADRERR;
 		info.si_addr = (void __user *)sun4v_get_vaddr(regs);
@@ -2368,6 +2375,7 @@ static void do_fpe_common(struct pt_regs *regs)
 			regs->tpc &= 0xffffffff;
 			regs->tnpc &= 0xffffffff;
 		}
+		clear_siginfo(&info);
 		info.si_signo = SIGFPE;
 		info.si_errno = 0;
 		info.si_addr = (void __user *)regs->tpc;
@@ -2440,6 +2448,7 @@ void do_tof(struct pt_regs *regs)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGEMT;
 	info.si_errno = 0;
 	info.si_code = EMT_TAGOVF;
@@ -2465,6 +2474,7 @@ void do_div0(struct pt_regs *regs)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGFPE;
 	info.si_errno = 0;
 	info.si_code = FPE_INTDIV;
@@ -2666,6 +2676,7 @@ void do_illegal_instruction(struct pt_regs *regs)
 			}
 		}
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_ILLOPC;
@@ -2692,6 +2703,7 @@ void mem_address_unaligned(struct pt_regs *regs, unsigned long sfar, unsigned lo
 	if (is_no_fault_exception(regs))
 		return;
 
+	clear_siginfo(&info);
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_ADRALN;
@@ -2717,6 +2729,7 @@ void sun4v_do_mna(struct pt_regs *regs, unsigned long addr, unsigned long type_c
 	if (is_no_fault_exception(regs))
 		return;
 
+	clear_siginfo(&info);
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_ADRALN;
@@ -2785,6 +2798,7 @@ void do_privop(struct pt_regs *regs)
 		regs->tpc &= 0xffffffff;
 		regs->tnpc &= 0xffffffff;
 	}
+	clear_siginfo(&info);
 	info.si_signo = SIGILL;
 	info.si_errno = 0;
 	info.si_code = ILL_PRVOPC;