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Diffstat (limited to 'arch/um/sys-i386/signal.c')
-rw-r--r--arch/um/sys-i386/signal.c107
1 files changed, 69 insertions, 38 deletions
diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c
index 7cd1a82dc8c2..f5d0e1c37ea2 100644
--- a/arch/um/sys-i386/signal.c
+++ b/arch/um/sys-i386/signal.c
@@ -19,7 +19,7 @@
#include "skas.h"
static int copy_sc_from_user_skas(struct pt_regs *regs,
- struct sigcontext *from)
+ struct sigcontext __user *from)
{
struct sigcontext sc;
unsigned long fpregs[HOST_FP_SIZE];
@@ -57,8 +57,8 @@ static int copy_sc_from_user_skas(struct pt_regs *regs,
return(0);
}
-int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
- struct pt_regs *regs)
+int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate __user *to_fp,
+ struct pt_regs *regs, unsigned long sp)
{
struct sigcontext sc;
unsigned long fpregs[HOST_FP_SIZE];
@@ -72,7 +72,7 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
sc.edi = REGS_EDI(regs->regs.skas.regs);
sc.esi = REGS_ESI(regs->regs.skas.regs);
sc.ebp = REGS_EBP(regs->regs.skas.regs);
- sc.esp = REGS_SP(regs->regs.skas.regs);
+ sc.esp = sp;
sc.ebx = REGS_EBX(regs->regs.skas.regs);
sc.edx = REGS_EDX(regs->regs.skas.regs);
sc.ecx = REGS_ECX(regs->regs.skas.regs);
@@ -92,7 +92,7 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
"errno = %d\n", err);
return(1);
}
- to_fp = (to_fp ? to_fp : (struct _fpstate *) (to + 1));
+ to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
sc.fpstate = to_fp;
if(err)
@@ -113,10 +113,11 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
* saved pointer is in the kernel, but the sigcontext is in userspace, so we
* copy_to_user it.
*/
-int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
+int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
int fpsize)
{
- struct _fpstate *to_fp, *from_fp;
+ struct _fpstate *to_fp;
+ struct _fpstate __user *from_fp;
unsigned long sigs;
int err;
@@ -131,20 +132,28 @@ int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
return(err);
}
-int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
- struct sigcontext *from, int fpsize)
+int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate __user *fp,
+ struct sigcontext *from, int fpsize, unsigned long sp)
{
- struct _fpstate *to_fp, *from_fp;
+ struct _fpstate __user *to_fp;
+ struct _fpstate *from_fp;
int err;
- to_fp = (fp ? fp : (struct _fpstate *) (to + 1));
+ to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
from_fp = from->fpstate;
err = copy_to_user(to, from, sizeof(*to));
+
+ /* The SP in the sigcontext is the updated one for the signal
+ * delivery. The sp passed in is the original, and this needs
+ * to be restored, so we stick it in separately.
+ */
+ err |= copy_to_user(&SC_SP(to), sp, sizeof(sp));
+
if(from_fp != NULL){
err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
err |= copy_to_user(to_fp, from_fp, fpsize);
}
- return(err);
+ return err;
}
#endif
@@ -158,15 +167,15 @@ static int copy_sc_from_user(struct pt_regs *to, void __user *from)
return(ret);
}
-static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
- struct pt_regs *from)
+static int copy_sc_to_user(struct sigcontext *to, struct _fpstate __user *fp,
+ struct pt_regs *from, unsigned long sp)
{
return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
- sizeof(*fp)),
- copy_sc_to_user_skas(to, fp, from)));
+ sizeof(*fp), sp),
+ copy_sc_to_user_skas(to, fp, from, sp)));
}
-static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp,
+static int copy_ucontext_to_user(struct ucontext __user *uc, struct _fpstate __user *fp,
sigset_t *set, unsigned long sp)
{
int err = 0;
@@ -174,14 +183,14 @@ static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp,
err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
- err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs);
+ err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
return(err);
}
struct sigframe
{
- char *pretcode;
+ char __user *pretcode;
int sig;
struct sigcontext sc;
struct _fpstate fpstate;
@@ -191,10 +200,10 @@ struct sigframe
struct rt_sigframe
{
- char *pretcode;
+ char __user *pretcode;
int sig;
- struct siginfo *pinfo;
- void *puc;
+ struct siginfo __user *pinfo;
+ void __user *puc;
struct siginfo info;
struct ucontext uc;
struct _fpstate fpstate;
@@ -206,21 +215,32 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig,
sigset_t *mask)
{
struct sigframe __user *frame;
- void *restorer;
+ void __user *restorer;
+ unsigned long save_sp = PT_REGS_SP(regs);
int err = 0;
stack_top &= -8UL;
- frame = (struct sigframe *) stack_top - 1;
+ frame = (struct sigframe __user *) stack_top - 1;
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return 1;
- restorer = (void *) frame->retcode;
+ restorer = frame->retcode;
if(ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;
+ /* Update SP now because the page fault handler refuses to extend
+ * the stack if the faulting address is too far below the current
+ * SP, which frame now certainly is. If there's an error, the original
+ * value is restored on the way out.
+ * When writing the sigcontext to the stack, we have to write the
+ * original value, so that's passed to copy_sc_to_user, which does
+ * the right thing with it.
+ */
+ PT_REGS_SP(regs) = (unsigned long) frame;
+
err |= __put_user(restorer, &frame->pretcode);
err |= __put_user(sig, &frame->sig);
- err |= copy_sc_to_user(&frame->sc, NULL, regs);
+ err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
err |= __put_user(mask->sig[0], &frame->sc.oldmask);
if (_NSIG_WORDS > 1)
err |= __copy_to_user(&frame->extramask, &mask->sig[1],
@@ -238,7 +258,7 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig,
err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
if(err)
- return(err);
+ goto err;
PT_REGS_SP(regs) = (unsigned long) frame;
PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
@@ -248,7 +268,11 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig,
if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
ptrace_notify(SIGTRAP);
- return(0);
+ return 0;
+
+err:
+ PT_REGS_SP(regs) = save_sp;
+ return err;
}
int setup_signal_stack_si(unsigned long stack_top, int sig,
@@ -256,25 +280,29 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
siginfo_t *info, sigset_t *mask)
{
struct rt_sigframe __user *frame;
- void *restorer;
+ void __user *restorer;
+ unsigned long save_sp = PT_REGS_SP(regs);
int err = 0;
stack_top &= -8UL;
- frame = (struct rt_sigframe *) stack_top - 1;
+ frame = (struct rt_sigframe __user *) stack_top - 1;
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return 1;
- restorer = (void *) frame->retcode;
+ restorer = frame->retcode;
if(ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;
+ /* See comment above about why this is here */
+ PT_REGS_SP(regs) = (unsigned long) frame;
+
err |= __put_user(restorer, &frame->pretcode);
err |= __put_user(sig, &frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, info);
err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
- PT_REGS_SP(regs));
+ save_sp);
/*
* This is movl $,%eax ; int $0x80
@@ -288,9 +316,8 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
if(err)
- return(err);
+ goto err;
- PT_REGS_SP(regs) = (unsigned long) frame;
PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
PT_REGS_EAX(regs) = (unsigned long) sig;
PT_REGS_EDX(regs) = (unsigned long) &frame->info;
@@ -298,13 +325,17 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
ptrace_notify(SIGTRAP);
- return(0);
+ return 0;
+
+err:
+ PT_REGS_SP(regs) = save_sp;
+ return err;
}
long sys_sigreturn(struct pt_regs regs)
{
unsigned long sp = PT_REGS_SP(&current->thread.regs);
- struct sigframe __user *frame = (struct sigframe *)(sp - 8);
+ struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
sigset_t set;
struct sigcontext __user *sc = &frame->sc;
unsigned long __user *oldmask = &sc->oldmask;
@@ -336,8 +367,8 @@ long sys_sigreturn(struct pt_regs regs)
long sys_rt_sigreturn(struct pt_regs regs)
{
- unsigned long __user sp = PT_REGS_SP(&current->thread.regs);
- struct rt_sigframe __user *frame = (struct rt_sigframe *) (sp - 4);
+ unsigned long sp = PT_REGS_SP(&current->thread.regs);
+ struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (sp - 4);
sigset_t set;
struct ucontext __user *uc = &frame->uc;
int sig_size = _NSIG_WORDS * sizeof(unsigned long);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.