From 3eb0f5193b497083391aa05d35210d5645211eef Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 17 Apr 2018 15:26:37 -0500 Subject: 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" --- arch/s390/kernel/traps.c | 5 ++++- arch/s390/mm/fault.c | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c index a5297a22bc1e..3ba649d8aa5a 100644 --- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -47,6 +47,7 @@ void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) siginfo_t info; if (user_mode(regs)) { + clear_siginfo(&info); info.si_signo = si_signo; info.si_errno = 0; info.si_code = si_code; @@ -86,6 +87,7 @@ void do_per_trap(struct pt_regs *regs) return; if (!current->ptrace) return; + clear_siginfo(&info); info.si_signo = SIGTRAP; info.si_errno = 0; info.si_code = TRAP_HWBKPT; @@ -165,7 +167,6 @@ void translation_exception(struct pt_regs *regs) void illegal_op(struct pt_regs *regs) { - siginfo_t info; __u8 opcode[6]; __u16 __user *location; int is_uprobe_insn = 0; @@ -178,6 +179,8 @@ void illegal_op(struct pt_regs *regs) return; if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) { if (current->ptrace) { + siginfo_t info; + clear_siginfo(&info); info.si_signo = SIGTRAP; info.si_errno = 0; info.si_code = TRAP_BRKPT; diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 93faeca52284..b3ff0e8e5860 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -268,6 +268,7 @@ static noinline void do_sigsegv(struct pt_regs *regs, int si_code) struct siginfo si; report_user_fault(regs, SIGSEGV, 1); + clear_siginfo(&si); si.si_signo = SIGSEGV; si.si_errno = 0; si.si_code = si_code; @@ -323,6 +324,7 @@ static noinline void do_sigbus(struct pt_regs *regs) * Send a sigbus, regardless of whether we were in kernel * or user mode. */ + clear_siginfo(&si); si.si_signo = SIGBUS; si.si_errno = 0; si.si_code = BUS_ADRERR; -- cgit v1.2.3 From 9507a5d01254b96d1b90225b3037e9143149fdc6 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sun, 15 Apr 2018 19:58:32 -0500 Subject: signal/s390: Use force_sig_fault where appropriate Filling in struct siginfo before calling force_sig_info a tedious and error prone process, where once in a great while the wrong fields are filled out, and siginfo has been inconsistently cleared. Simplify this process by using the helper force_sig_fault. Which takes as a parameters all of the information it needs, ensures all of the fiddly bits of filling in struct siginfo are done properly and then calls force_sig_info. In short about a 5 line reduction in code for every time force_sig_info is called, which makes the calling function clearer. Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: linux-s390@vger.kernel.org Acked-by: Martin Schwidefsky >schwidefsky@de.ibm.com> Signed-off-by: "Eric W. Biederman" --- arch/s390/kernel/traps.c | 32 ++++++-------------------------- arch/s390/mm/fault.c | 23 ++++++----------------- 2 files changed, 12 insertions(+), 43 deletions(-) (limited to 'arch/s390') diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c index 3ba649d8aa5a..8003b38c1688 100644 --- a/arch/s390/kernel/traps.c +++ b/arch/s390/kernel/traps.c @@ -44,15 +44,8 @@ int is_valid_bugaddr(unsigned long addr) void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) { - siginfo_t info; - if (user_mode(regs)) { - clear_siginfo(&info); - info.si_signo = si_signo; - info.si_errno = 0; - info.si_code = si_code; - info.si_addr = get_trap_ip(regs); - force_sig_info(si_signo, &info, current); + force_sig_fault(si_signo, si_code, get_trap_ip(regs), current); report_user_fault(regs, si_signo, 0); } else { const struct exception_table_entry *fixup; @@ -81,19 +74,12 @@ NOKPROBE_SYMBOL(do_trap); void do_per_trap(struct pt_regs *regs) { - siginfo_t info; - if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP) return; if (!current->ptrace) return; - clear_siginfo(&info); - info.si_signo = SIGTRAP; - info.si_errno = 0; - info.si_code = TRAP_HWBKPT; - info.si_addr = - (void __force __user *) current->thread.per_event.address; - force_sig_info(SIGTRAP, &info, current); + force_sig_fault(SIGTRAP, TRAP_HWBKPT, + (void __force __user *) current->thread.per_event.address, current); } NOKPROBE_SYMBOL(do_per_trap); @@ -178,15 +164,9 @@ void illegal_op(struct pt_regs *regs) if (get_user(*((__u16 *) opcode), (__u16 __user *) location)) return; if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) { - if (current->ptrace) { - siginfo_t info; - clear_siginfo(&info); - info.si_signo = SIGTRAP; - info.si_errno = 0; - info.si_code = TRAP_BRKPT; - info.si_addr = location; - force_sig_info(SIGTRAP, &info, current); - } else + if (current->ptrace) + force_sig_fault(SIGTRAP, TRAP_BRKPT, location, current); + else signal = SIGILL; #ifdef CONFIG_UPROBES } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) { diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index b3ff0e8e5860..e074480d3598 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -265,15 +265,10 @@ void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault) */ static noinline void do_sigsegv(struct pt_regs *regs, int si_code) { - struct siginfo si; - report_user_fault(regs, SIGSEGV, 1); - clear_siginfo(&si); - si.si_signo = SIGSEGV; - si.si_errno = 0; - si.si_code = si_code; - si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); - force_sig_info(SIGSEGV, &si, current); + force_sig_fault(SIGSEGV, si_code, + (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK), + current); } static noinline void do_no_context(struct pt_regs *regs) @@ -317,19 +312,13 @@ static noinline void do_low_address(struct pt_regs *regs) static noinline void do_sigbus(struct pt_regs *regs) { - struct task_struct *tsk = current; - struct siginfo si; - /* * Send a sigbus, regardless of whether we were in kernel * or user mode. */ - clear_siginfo(&si); - si.si_signo = SIGBUS; - si.si_errno = 0; - si.si_code = BUS_ADRERR; - si.si_addr = (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK); - force_sig_info(SIGBUS, &si, tsk); + force_sig_fault(SIGBUS, BUS_ADRERR, + (void __user *)(regs->int_parm_long & __FAIL_ADDR_MASK), + current); } static noinline int signal_return(struct pt_regs *regs) -- cgit v1.2.3