From f71dd7dc2dc989dc712b246a74d243e4b2c5f8a7 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Mon, 22 Jan 2018 14:37:25 -0600 Subject: signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed There are so many places that build struct siginfo by hand that at least one of them is bound to get it wrong. A handful of cases in the kernel arguably did just that when using the errno field of siginfo to pass no errno values to userspace. The usage is limited to a single si_code so at least does not mess up anything else. Encapsulate this questionable pattern in a helper function so that the userspace ABI is preserved. Update all of the places that use this pattern to use the new helper function. Signed-off-by: "Eric W. Biederman" --- arch/arm/kernel/ptrace.c | 8 +------- arch/arm64/kernel/ptrace.c | 6 ++++-- arch/powerpc/kernel/process.c | 9 ++------- arch/xtensa/kernel/ptrace.c | 8 +------- 4 files changed, 8 insertions(+), 23 deletions(-) (limited to 'arch') diff --git a/arch/arm/kernel/ptrace.c b/arch/arm/kernel/ptrace.c index 58e3771..7724b0f 100644 --- a/arch/arm/kernel/ptrace.c +++ b/arch/arm/kernel/ptrace.c @@ -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)); } /* diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 95daa14..6618036 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -190,21 +190,23 @@ static void ptrace_hbptriggered(struct perf_event *bp, #ifdef CONFIG_COMPAT if (is_compat_task()) { + int si_errno = 0; int i; for (i = 0; i < ARM_MAX_BRP; ++i) { if (current->thread.debug.hbp_break[i] == bp) { - info.si_errno = (i << 1) + 1; + si_errno = (i << 1) + 1; break; } } for (i = 0; i < ARM_MAX_WRP; ++i) { if (current->thread.debug.hbp_watch[i] == bp) { - info.si_errno = -((i << 1) + 1); + si_errno = -((i << 1) + 1); break; } } + force_sig_ptrace_errno_trap(si_errno, (void __user *)bkpt->trigger); } #endif force_sig_info(SIGTRAP, &info, current); diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index bfb48cf..4208cbe 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -603,19 +603,14 @@ EXPORT_SYMBOL(flush_all_to_thread); void do_send_trap(struct pt_regs *regs, unsigned long address, unsigned long error_code, int breakpt) { - siginfo_t info; - current->thread.trap_nr = TRAP_HWBKPT; if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code, 11, SIGSEGV) == NOTIFY_STOP) return; /* Deliver the signal to userspace */ - info.si_signo = SIGTRAP; - info.si_errno = breakpt; /* breakpoint or watchpoint id */ - info.si_code = TRAP_HWBKPT; - info.si_addr = (void __user *)address; - force_sig_info(SIGTRAP, &info, current); + force_sig_ptrace_errno_trap(breakpt, /* breakpoint or watchpoint id */ + (void __user *)address); } #else /* !CONFIG_PPC_ADV_DEBUG_REGS */ void do_break (struct pt_regs *regs, unsigned long address, diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c index e246196..c0845cb 100644 --- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -278,7 +278,6 @@ static void ptrace_hbptriggered(struct perf_event *bp, struct pt_regs *regs) { int i; - siginfo_t info; struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp); if (bp->attr.bp_type & HW_BREAKPOINT_X) { @@ -293,12 +292,7 @@ static void ptrace_hbptriggered(struct perf_event *bp, i = (i << 1) | 1; } - info.si_signo = SIGTRAP; - info.si_errno = i; - info.si_code = TRAP_HWBKPT; - info.si_addr = (void __user *)bkpt->address; - - force_sig_info(SIGTRAP, &info, current); + force_sig_ptrace_errno_trap(i, (void __user *)bkpt->address); } static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type) -- cgit v1.1