Fix a confusion between osigcontext and ucontext_t in the previous commit.

Since an osigcontext is smaller, if you check for a valid (much larger sized)
ucontext_t and it fails, we bogusly would reject the osigcontext as per
rev 1.378.  Instead, check for osigcontext range validity first, and
ucontext_t later.  This unbreaks Netscape.

Pointed to the right commit by:	peter

2 files changed, 32 insertions, 12 deletions

diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 1c0d37d..d5c8b9a 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -533,7 +533,7 @@ osendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
 	else {
 		/* Old FreeBSD-style arguments. */
 		sf.sf_arg2 = code;
-		sf.sf_addr = regs->tf_err;
+		sf.sf_addr = (register_t *)regs->tf_err;
 		sf.sf_ahu.sf_handler = catcher;
 	}
 
@@ -686,7 +686,7 @@ sendsig(catcher, sig, mask, code)
 	else {
 		/* Old FreeBSD-style arguments. */
 		sf.sf_siginfo = code;
-		sf.sf_addr = regs->tf_err;
+		sf.sf_addr = (register_t *)regs->tf_err;
 		sf.sf_ahu.sf_handler = catcher;
 	}
 
@@ -874,11 +874,21 @@ sigreturn(p, uap)
 	int cs, eflags;
 
 	ucp = uap->sigcntxp;
-	if (!useracc((caddr_t)ucp, sizeof(ucontext_t), VM_PROT_READ))
-		return(EFAULT);
 
-	if (((struct osigcontext *)uap->sigcntxp)->sc_trapno == 0x01d516)
-		return osigreturn(p, (struct osigreturn_args *)uap);
+	if (!useracc((caddr_t)ucp, sizeof(struct osigcontext), VM_PROT_READ))
+		return (EFAULT);
+	if (((struct osigcontext *)ucp)->sc_trapno == 0x01d516)
+		return (osigreturn(p, (struct osigreturn_args *)uap));
+
+	/*
+	 * Since ucp is not an osigcontext but a ucontext_t, we have to
+	 * check again if all of it is accessible.  A ucontext_t is
+	 * much larger, so instead of just checking for the pointer
+	 * being valid for the size of an osigcontext, now check for
+	 * it being valid for a whole, new-style ucontext_t.
+	 */
+	if (!useracc((caddr_t)ucp, sizeof(ucontext_t), VM_PROT_READ))
+		return (EFAULT);
 
 	regs = p->p_md.md_regs;
 	eflags = ucp->uc_mcontext.mc_eflags;
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 1c0d37d..d5c8b9a 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -533,7 +533,7 @@ osendsig(sig_t catcher, int sig, sigset_t *mask, u_long code)
 	else {
 		/* Old FreeBSD-style arguments. */
 		sf.sf_arg2 = code;
-		sf.sf_addr = regs->tf_err;
+		sf.sf_addr = (register_t *)regs->tf_err;
 		sf.sf_ahu.sf_handler = catcher;
 	}
 
@@ -686,7 +686,7 @@ sendsig(catcher, sig, mask, code)
 	else {
 		/* Old FreeBSD-style arguments. */
 		sf.sf_siginfo = code;
-		sf.sf_addr = regs->tf_err;
+		sf.sf_addr = (register_t *)regs->tf_err;
 		sf.sf_ahu.sf_handler = catcher;
 	}
 
@@ -874,11 +874,21 @@ sigreturn(p, uap)
 	int cs, eflags;
 
 	ucp = uap->sigcntxp;
-	if (!useracc((caddr_t)ucp, sizeof(ucontext_t), VM_PROT_READ))
-		return(EFAULT);
 
-	if (((struct osigcontext *)uap->sigcntxp)->sc_trapno == 0x01d516)
-		return osigreturn(p, (struct osigreturn_args *)uap);
+	if (!useracc((caddr_t)ucp, sizeof(struct osigcontext), VM_PROT_READ))
+		return (EFAULT);
+	if (((struct osigcontext *)ucp)->sc_trapno == 0x01d516)
+		return (osigreturn(p, (struct osigreturn_args *)uap));
+
+	/*
+	 * Since ucp is not an osigcontext but a ucontext_t, we have to
+	 * check again if all of it is accessible.  A ucontext_t is
+	 * much larger, so instead of just checking for the pointer
+	 * being valid for the size of an osigcontext, now check for
+	 * it being valid for a whole, new-style ucontext_t.
+	 */
+	if (!useracc((caddr_t)ucp, sizeof(ucontext_t), VM_PROT_READ))
+		return (EFAULT);
 
 	regs = p->p_md.md_regs;
 	eflags = ucp->uc_mcontext.mc_eflags;