signal: Don't use structure initializers for struct siginfo

The siginfo structure has all manners of holes with the result that a
structure initializer is not guaranteed to initialize all of the bits.
As we have to copy the structure to userspace don't even try to use
a structure initializer.  Instead use clear_siginfo followed by initializing
selected fields.  This gives a guarantee that uninitialized kernel memory
is not copied to userspace.

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

diff --git a/arch/arc/kernel/traps.c b/arch/arc/kernel/traps.c
index bcd7c9f..c720678 100644 (file)
--- a/arch/arc/kernel/traps.c
+++ b/arch/arc/kernel/traps.c
@@ -65,12 +65,14 @@ unhandled_exception(const char *str, struct pt_regs *regs, siginfo_t *info)
 #define DO_ERROR_INFO(signr, str, name, sicode) \
 int name(unsigned long address, struct pt_regs *regs) \
 {                                              \
-       siginfo_t info = {                      \
-               .si_signo = signr,              \
-               .si_errno = 0,                  \
-               .si_code  = sicode,             \
-               .si_addr = (void __user *)address,      \
-       };                                      \
+       siginfo_t info;                         \
+                                               \
+       clear_siginfo(&info);                   \
+       info.si_signo = signr;                  \
+       info.si_errno = 0;                      \
+       info.si_code  = sicode;                 \
+       info.si_addr = (void __user *)address;  \
+                                               \
        return unhandled_exception(str, regs, &info);\
 }
 

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index a88b6cc..53781f5 100644 (file)
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -209,12 +209,13 @@ NOKPROBE_SYMBOL(call_step_hook);
 static void send_user_sigtrap(int si_code)
 {
        struct pt_regs *regs = current_pt_regs();
-       siginfo_t info = {
-               .si_signo       = SIGTRAP,
-               .si_errno       = 0,
-               .si_code        = si_code,
-               .si_addr        = (void __user *)instruction_pointer(regs),
-       };
+       siginfo_t info;
+
+       clear_siginfo(&info);
+       info.si_signo   = SIGTRAP;
+       info.si_errno   = 0;
+       info.si_code    = si_code;
+       info.si_addr    = (void __user *)instruction_pointer(regs);
 
        if (WARN_ON(!user_mode(regs)))
                return;

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 0a1cf83..95daa14 100644 (file)
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -180,12 +180,13 @@ static void ptrace_hbptriggered(struct perf_event *bp,
                                struct pt_regs *regs)
 {
        struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
-       siginfo_t info = {
-               .si_signo       = SIGTRAP,
-               .si_errno       = 0,
-               .si_code        = TRAP_HWBKPT,
-               .si_addr        = (void __user *)(bkpt->trigger),
-       };
+       siginfo_t info;
+
+       clear_siginfo(&info);
+       info.si_signo   = SIGTRAP;
+       info.si_errno   = 0;
+       info.si_code    = TRAP_HWBKPT;
+       info.si_addr    = (void __user *)(bkpt->trigger);
 
 #ifdef CONFIG_COMPAT
        if (is_compat_task()) {

diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index 127d7c1..03253c4 100644 (file)
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -21,8 +21,9 @@ extern void die_if_kernel(char *, struct pt_regs *, long);
 
 int send_fault_sig(struct pt_regs *regs)
 {
-       siginfo_t siginfo = { 0, 0, 0, };
+       siginfo_t siginfo;
 
+       clear_siginfo(&siginfo);
        siginfo.si_signo = current->thread.signo;
        siginfo.si_code = current->thread.code;
        siginfo.si_addr = (void *)current->thread.faddr;

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 5d19ed0..0ae4a73 100644 (file)
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -699,11 +699,12 @@ static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
 asmlinkage void do_ov(struct pt_regs *regs)
 {
        enum ctx_state prev_state;
-       siginfo_t info = {
-               .si_signo = SIGFPE,
-               .si_code = FPE_INTOVF,
-               .si_addr = (void __user *)regs->cp0_epc,
-       };
+       siginfo_t info;
+
+       clear_siginfo(&info);
+       info.si_signo = SIGFPE;
+       info.si_code = FPE_INTOVF;
+       info.si_addr = (void __user *)regs->cp0_epc;
 
        prev_state = exception_enter();
        die_if_kernel("Integer overflow", regs);
@@ -721,7 +722,11 @@ asmlinkage void do_ov(struct pt_regs *regs)
 void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
                     struct task_struct *tsk)
 {
-       struct siginfo si = { .si_addr = fault_addr, .si_signo = SIGFPE };
+       struct siginfo si;
+
+       clear_siginfo(&si);
+       si.si_addr = fault_addr;
+       si.si_signo = SIGFPE;
 
        if (fcr31 & FPU_CSR_INV_X)
                si.si_code = FPE_FLTINV;
@@ -739,9 +744,10 @@ void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
 
 int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31)
 {
-       struct siginfo si = { 0 };
+       struct siginfo si;
        struct vm_area_struct *vma;
 
+       clear_siginfo(&si);
        switch (sig) {
        case 0:
                return 0;
@@ -890,9 +896,10 @@ out:
 void do_trap_or_bp(struct pt_regs *regs, unsigned int code, int si_code,
        const char *str)
 {
-       siginfo_t info = { 0 };
+       siginfo_t info;
        char b[40];
 
+       clear_siginfo(&info);
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
        if (kgdb_ll_trap(DIE_TRAP, str, regs, code, current->thread.trap_nr,
                         SIGTRAP) == NOTIFY_STOP)
@@ -1499,9 +1506,13 @@ asmlinkage void do_mdmx(struct pt_regs *regs)
  */
 asmlinkage void do_watch(struct pt_regs *regs)
 {
-       siginfo_t info = { .si_signo = SIGTRAP, .si_code = TRAP_HWBKPT };
+       siginfo_t info;
        enum ctx_state prev_state;
 
+       clear_siginfo(&info);
+       info.si_signo = SIGTRAP;
+       info.si_code = TRAP_HWBKPT;
+
        prev_state = exception_enter();
        /*
         * Clear WP (bit 22) bit of cause register so we don't loop

diff --git a/arch/tile/kernel/single_step.c b/arch/tile/kernel/single_step.c
index de3eae8..479d803 100644 (file)
--- a/arch/tile/kernel/single_step.c
+++ b/arch/tile/kernel/single_step.c
@@ -163,11 +163,13 @@ static tilepro_bundle_bits rewrite_load_store_unaligned(
         * actual bad address in an SPR, which it doesn't.
         */
        if (align_ctl == 0) {
-               siginfo_t info = {
-                       .si_signo = SIGBUS,
-                       .si_code = BUS_ADRALN,
-                       .si_addr = addr
-               };
+               siginfo_t info;
+
+               clear_siginfo(&info);
+               info.si_signo = SIGBUS;
+               info.si_code = BUS_ADRALN;
+               info.si_addr = addr;
+
                trace_unhandled_signal("unaligned trap", regs,
                                       (unsigned long)addr, SIGBUS);
                force_sig_info(info.si_signo, &info, current);
@@ -210,11 +212,13 @@ static tilepro_bundle_bits rewrite_load_store_unaligned(
        }
 
        if (err) {
-               siginfo_t info = {
-                       .si_signo = SIGBUS,
-                       .si_code = BUS_ADRALN,
-                       .si_addr = addr
-               };
+               siginfo_t info;
+
+               clear_siginfo(&info);
+               info.si_signo = SIGBUS;
+               info.si_code = BUS_ADRALN;
+               info.si_addr = addr;
+
                trace_unhandled_signal("bad address for unaligned fixup", regs,
                                       (unsigned long)addr, SIGBUS);
                force_sig_info(info.si_signo, &info, current);

diff --git a/arch/tile/kernel/traps.c b/arch/tile/kernel/traps.c
index 9b08c60..83a7186 100644 (file)
--- a/arch/tile/kernel/traps.c
+++ b/arch/tile/kernel/traps.c
@@ -256,12 +256,14 @@ static int do_bpt(struct pt_regs *regs)
 void __kprobes do_trap(struct pt_regs *regs, int fault_num,
                       unsigned long reason)
 {
-       siginfo_t info = { 0 };
+       siginfo_t info;
        int signo, code;
        unsigned long address = 0;
        tile_bundle_bits instr;
        int is_kernel = !user_mode(regs);
 
+       clear_siginfo(&info);
+
        /* Handle breakpoints, etc. */
        if (is_kernel && fault_num == INT_ILL && do_bpt(regs))
                return;

diff --git a/arch/tile/kernel/unaligned.c b/arch/tile/kernel/unaligned.c
index 8149c38..77a0b6b 100644 (file)
--- a/arch/tile/kernel/unaligned.c
+++ b/arch/tile/kernel/unaligned.c
@@ -980,11 +980,13 @@ void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
        }
 
        if ((align_ctl == 0) || unexpected) {
-               siginfo_t info = {
-                       .si_signo = SIGBUS,
-                       .si_code = BUS_ADRALN,
-                       .si_addr = (unsigned char __user *)0
-               };
+               siginfo_t info;
+
+               clear_siginfo(&info);
+               info.si_signo = SIGBUS;
+               info.si_code = BUS_ADRALN;
+               info.si_addr = (unsigned char __user *)0;
+
                if (unaligned_printk)
                        pr_info("Unalign bundle: unexp @%llx, %llx\n",
                                (unsigned long long)regs->pc,
@@ -1396,11 +1398,12 @@ void jit_bundle_gen(struct pt_regs *regs, tilegx_bundle_bits bundle,
                                      &frag, sizeof(frag));
                if (status) {
                        /* Fail to copy JIT into user land. send SIGSEGV. */
-                       siginfo_t info = {
-                               .si_signo = SIGSEGV,
-                               .si_code = SEGV_MAPERR,
-                               .si_addr = (void __user *)&jit_code_area[idx]
-                       };
+                       siginfo_t info;
+
+                       clear_siginfo(&info);
+                       info.si_signo = SIGSEGV;
+                       info.si_code = SEGV_MAPERR;
+                       info.si_addr = (void __user *)&jit_code_area[idx];
 
                        pr_warn("Unalign fixup: pid=%d %s jit_code_area=%llx\n",
                                current->pid, current->comm,
@@ -1511,11 +1514,12 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
         * If so, we will trigger SIGBUS.
         */
        if ((regs->sp & 0x7) || (regs->ex1) || (align_ctl < 0)) {
-               siginfo_t info = {
-                       .si_signo = SIGBUS,
-                       .si_code = BUS_ADRALN,
-                       .si_addr = (unsigned char __user *)0
-               };
+               siginfo_t info;
+
+               clear_siginfo(&info);
+               info.si_signo = SIGBUS;
+               info.si_code = BUS_ADRALN;
+               info.si_addr = (unsigned char __user *)0;
 
                if (unaligned_printk)
                        pr_info("Unalign fixup: %d %llx @%llx\n",
@@ -1535,11 +1539,13 @@ void do_unaligned(struct pt_regs *regs, int vecnum)
        pc = (tilegx_bundle_bits __user *)(regs->pc);
        if (get_user(bundle, pc) != 0) {
                /* Probably never be here since pc is valid user address.*/
-               siginfo_t info = {
-                       .si_signo = SIGSEGV,
-                       .si_code = SEGV_MAPERR,
-                       .si_addr = (void __user *)pc
-               };
+               siginfo_t info;
+
+               clear_siginfo(&info);
+               info.si_signo = SIGSEGV;
+               info.si_code = SEGV_MAPERR;
+               info.si_addr = (void __user *)pc;
+
                pr_err("Couldn't read instruction at %p trying to step\n", pc);
                trace_unhandled_signal("segfault in unalign fixup", regs,
                                       (unsigned long)info.si_addr, SIGSEGV);

diff --git a/kernel/signal.c b/kernel/signal.c
index 4976f05..f14492f 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3163,8 +3163,9 @@ do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
 
 static int do_tkill(pid_t tgid, pid_t pid, int sig)
 {
-       struct siginfo info = {};
+       struct siginfo info;
 
+       clear_siginfo(&info);
        info.si_signo = sig;
        info.si_errno = 0;
        info.si_code = SI_TKILL;