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-rw-r--r--arch/um/sys-i386/signal.c59
-rw-r--r--arch/um/sys-x86_64/signal.c56
2 files changed, 85 insertions, 30 deletions
diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c
index 7cd1a82dc8c2..33a40f5ef0d2 100644
--- a/arch/um/sys-i386/signal.c
+++ b/arch/um/sys-i386/signal.c
@@ -58,7 +58,7 @@ static int copy_sc_from_user_skas(struct pt_regs *regs,
}
int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
- struct pt_regs *regs)
+ 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);
@@ -132,7 +132,7 @@ int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
}
int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
- struct sigcontext *from, int fpsize)
+ struct sigcontext *from, int fpsize, unsigned long sp)
{
struct _fpstate *to_fp, *from_fp;
int err;
@@ -140,11 +140,18 @@ int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
to_fp = (fp ? fp : (struct _fpstate *) (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
@@ -159,11 +166,11 @@ static int copy_sc_from_user(struct pt_regs *to, void __user *from)
}
static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
- struct pt_regs *from)
+ 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,
@@ -174,7 +181,7 @@ 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);
}
@@ -207,6 +214,7 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig,
{
struct sigframe __user *frame;
void *restorer;
+ unsigned long save_sp = PT_REGS_SP(regs);
int err = 0;
stack_top &= -8UL;
@@ -218,9 +226,19 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig,
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 +256,7 @@ 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 +266,11 @@ 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,
@@ -257,6 +279,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
{
struct rt_sigframe __user *frame;
void *restorer;
+ unsigned long save_sp = PT_REGS_SP(regs);
int err = 0;
stack_top &= -8UL;
@@ -268,13 +291,16 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
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 +314,8 @@ 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;
@@ -298,7 +323,11 @@ 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)
diff --git a/arch/um/sys-x86_64/signal.c b/arch/um/sys-x86_64/signal.c
index fe1d065332b1..e75c4e1838b0 100644
--- a/arch/um/sys-x86_64/signal.c
+++ b/arch/um/sys-x86_64/signal.c
@@ -55,7 +55,8 @@ static int copy_sc_from_user_skas(struct pt_regs *regs,
}
int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
- struct pt_regs *regs, unsigned long mask)
+ struct pt_regs *regs, unsigned long mask,
+ unsigned long sp)
{
struct faultinfo * fi = &current->thread.arch.faultinfo;
int err = 0;
@@ -70,7 +71,11 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
err |= PUTREG(regs, RDI, to, rdi);
err |= PUTREG(regs, RSI, to, rsi);
err |= PUTREG(regs, RBP, to, rbp);
- err |= PUTREG(regs, RSP, to, rsp);
+ /* Must use orignal RSP, which is passed in, rather than what's in
+ * the pt_regs, because that's already been updated to point at the
+ * signal frame.
+ */
+ err |= __put_user(sp, &to->rsp);
err |= PUTREG(regs, RBX, to, rbx);
err |= PUTREG(regs, RDX, to, rdx);
err |= PUTREG(regs, RCX, to, rcx);
@@ -102,7 +107,7 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
#ifdef CONFIG_MODE_TT
int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
- int fpsize)
+ int fpsize)
{
struct _fpstate *to_fp, *from_fp;
unsigned long sigs;
@@ -120,7 +125,7 @@ int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
}
int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
- struct sigcontext *from, int fpsize)
+ struct sigcontext *from, int fpsize, unsigned long sp)
{
struct _fpstate *to_fp, *from_fp;
int err;
@@ -128,11 +133,17 @@ int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
to_fp = (fp ? fp : (struct _fpstate *) (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
@@ -148,11 +159,12 @@ static int copy_sc_from_user(struct pt_regs *to, void __user *from)
}
static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
- struct pt_regs *from, unsigned long mask)
+ struct pt_regs *from, unsigned long mask,
+ 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, mask)));
+ sizeof(*fp), sp),
+ copy_sc_to_user_skas(to, fp, from, mask, sp)));
}
struct rt_sigframe
@@ -170,6 +182,7 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
{
struct rt_sigframe __user *frame;
struct _fpstate __user *fp = NULL;
+ unsigned long save_sp = PT_REGS_RSP(regs);
int err = 0;
struct task_struct *me = current;
@@ -193,14 +206,25 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
goto out;
}
+ /* 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_RSP(regs) = (unsigned long) frame;
+
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
- err |= __put_user(sas_ss_flags(PT_REGS_SP(regs)),
+ err |= __put_user(sas_ss_flags(save_sp),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
- err |= copy_sc_to_user(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
+ err |= copy_sc_to_user(&frame->uc.uc_mcontext, fp, regs, set->sig[0],
+ save_sp);
err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
if (sizeof(*set) == 16) {
__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
@@ -217,10 +241,10 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
else
/* could use a vstub here */
- goto out;
+ goto restore_sp;
if (err)
- goto out;
+ goto restore_sp;
/* Set up registers for signal handler */
{
@@ -238,10 +262,12 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
PT_REGS_RSI(regs) = (unsigned long) &frame->info;
PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
-
- PT_REGS_RSP(regs) = (unsigned long) frame;
out:
- return(err);
+ return err;
+
+restore_sp:
+ PT_REGS_RSP(regs) = save_sp;
+ return err;
}
long sys_rt_sigreturn(struct pt_regs *regs)
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.