Merge branch 'for-next/signal' into for-next/core

* for-next/signal:
  : Signal handling cleanups
  arm64/signal: Only read new data when parsing the ZT context
  arm64/signal: Only read new data when parsing the ZA context
  arm64/signal: Only read new data when parsing the SVE context
  arm64/signal: Avoid rereading context frame sizes
  arm64/signal: Make interface for restore_fpsimd_context() consistent
  arm64/signal: Remove redundant size validation from parse_user_sigframe()
  arm64/signal: Don't redundantly verify FPSIMD magic

Author: ctmarinas

arch/arm64/kernel/signal.c

@@ -170,6 +170,19 @@ static void __user *apply_user_offset(
 	return base + offset;
 }
 
+struct user_ctxs {
+	struct fpsimd_context __user *fpsimd;
+	u32 fpsimd_size;
+	struct sve_context __user *sve;
+	u32 sve_size;
+	struct tpidr2_context __user *tpidr2;
+	u32 tpidr2_size;
+	struct za_context __user *za;
+	u32 za_size;
+	struct zt_context __user *zt;
+	u32 zt_size;
+};
+
 static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
 {
 	struct user_fpsimd_state const *fpsimd =
@@ -188,25 +201,20 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
 	return err ? -EFAULT : 0;
 }
 
-static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
+static int restore_fpsimd_context(struct user_ctxs *user)
 {
 	struct user_fpsimd_state fpsimd;
-	__u32 magic, size;
 	int err = 0;
 
-	/* check the magic/size information */
-	__get_user_error(magic, &ctx->head.magic, err);
-	__get_user_error(size, &ctx->head.size, err);
-	if (err)
-		return -EFAULT;
-	if (magic != FPSIMD_MAGIC || size != sizeof(struct fpsimd_context))
+	/* check the size information */
+	if (user->fpsimd_size != sizeof(struct fpsimd_context))
 		return -EINVAL;
 
 	/* copy the FP and status/control registers */
-	err = __copy_from_user(fpsimd.vregs, ctx->vregs,
+	err = __copy_from_user(fpsimd.vregs, &(user->fpsimd->vregs),
 			       sizeof(fpsimd.vregs));
-	__get_user_error(fpsimd.fpsr, &ctx->fpsr, err);
-	__get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
+	__get_user_error(fpsimd.fpsr, &(user->fpsimd->fpsr), err);
+	__get_user_error(fpsimd.fpcr, &(user->fpsimd->fpcr), err);
 
 	clear_thread_flag(TIF_SVE);
 	current->thread.fp_type = FP_STATE_FPSIMD;
@@ -219,14 +227,6 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
 }
 
 
-struct user_ctxs {
-	struct fpsimd_context __user *fpsimd;
-	struct sve_context __user *sve;
-	struct tpidr2_context __user *tpidr2;
-	struct za_context __user *za;
-	struct zt_context __user *zt;
-};
-
 #ifdef CONFIG_ARM64_SVE
 
 static int preserve_sve_context(struct sve_context __user *ctx)
@@ -271,15 +271,20 @@ static int preserve_sve_context(struct sve_context __user *ctx)
 
 static int restore_sve_fpsimd_context(struct user_ctxs *user)
 {
-	int err;
+	int err = 0;
 	unsigned int vl, vq;
 	struct user_fpsimd_state fpsimd;
-	struct sve_context sve;
+	u16 user_vl, flags;
 
-	if (__copy_from_user(&sve, user->sve, sizeof(sve)))
-		return -EFAULT;
+	if (user->sve_size < sizeof(*user->sve))
+		return -EINVAL;
+
+	__get_user_error(user_vl, &(user->sve->vl), err);
+	__get_user_error(flags, &(user->sve->flags), err);
+	if (err)
+		return err;
 
-	if (sve.flags & SVE_SIG_FLAG_SM) {
+	if (flags & SVE_SIG_FLAG_SM) {
 		if (!system_supports_sme())
 			return -EINVAL;
 
@@ -291,19 +296,19 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user)
 		vl = task_get_sve_vl(current);
 	}
 
-	if (sve.vl != vl)
+	if (user_vl != vl)
 		return -EINVAL;
 
-	if (sve.head.size <= sizeof(*user->sve)) {
+	if (user->sve_size == sizeof(*user->sve)) {
 		clear_thread_flag(TIF_SVE);
 		current->thread.svcr &= ~SVCR_SM_MASK;
 		current->thread.fp_type = FP_STATE_FPSIMD;
 		goto fpsimd_only;
 	}
 
-	vq = sve_vq_from_vl(sve.vl);
+	vq = sve_vq_from_vl(vl);
 
-	if (sve.head.size < SVE_SIG_CONTEXT_SIZE(vq))
+	if (user->sve_size < SVE_SIG_CONTEXT_SIZE(vq))
 		return -EINVAL;
 
 	/*
@@ -329,7 +334,7 @@ static int restore_sve_fpsimd_context(struct user_ctxs *user)
 	if (err)
 		return -EFAULT;
 
-	if (sve.flags & SVE_SIG_FLAG_SM)
+	if (flags & SVE_SIG_FLAG_SM)
 		current->thread.svcr |= SVCR_SM_MASK;
 	else
 		set_thread_flag(TIF_SVE);
@@ -383,7 +388,9 @@ static int restore_tpidr2_context(struct user_ctxs *user)
 	u64 tpidr2_el0;
 	int err = 0;
 
-	/* Magic and size were validated deciding to call this function */
+	if (user->tpidr2_size != sizeof(*user->tpidr2))
+		return -EINVAL;
+
 	__get_user_error(tpidr2_el0, &user->tpidr2->tpidr2, err);
 	if (!err)
 		current->thread.tpidr2_el0 = tpidr2_el0;
@@ -428,24 +435,28 @@ static int preserve_za_context(struct za_context __user *ctx)
 
 static int restore_za_context(struct user_ctxs *user)
 {
-	int err;
+	int err = 0;
 	unsigned int vq;
-	struct za_context za;
+	u16 user_vl;
 
-	if (__copy_from_user(&za, user->za, sizeof(za)))
-		return -EFAULT;
+	if (user->za_size < sizeof(*user->za))
+		return -EINVAL;
+
+	__get_user_error(user_vl, &(user->za->vl), err);
+	if (err)
+		return err;
 
-	if (za.vl != task_get_sme_vl(current))
+	if (user_vl != task_get_sme_vl(current))
 		return -EINVAL;
 
-	if (za.head.size <= sizeof(*user->za)) {
+	if (user->za_size == sizeof(*user->za)) {
 		current->thread.svcr &= ~SVCR_ZA_MASK;
 		return 0;
 	}
 
-	vq = sve_vq_from_vl(za.vl);
+	vq = sve_vq_from_vl(user_vl);
 
-	if (za.head.size < ZA_SIG_CONTEXT_SIZE(vq))
+	if (user->za_size < ZA_SIG_CONTEXT_SIZE(vq))
 		return -EINVAL;
 
 	/*
@@ -510,19 +521,19 @@ static int preserve_zt_context(struct zt_context __user *ctx)
 static int restore_zt_context(struct user_ctxs *user)
 {
 	int err;
-	struct zt_context zt;
+	u16 nregs;
 
 	/* ZA must be restored first for this check to be valid */
 	if (!thread_za_enabled(&current->thread))
 		return -EINVAL;
 
-	if (__copy_from_user(&zt, user->zt, sizeof(zt)))
-		return -EFAULT;
-
-	if (zt.nregs != 1)
+	if (user->zt_size != ZT_SIG_CONTEXT_SIZE(1))
 		return -EINVAL;
 
-	if (zt.head.size != ZT_SIG_CONTEXT_SIZE(zt.nregs))
+	if (__copy_from_user(&nregs, &(user->zt->nregs), sizeof(nregs)))
+		return -EFAULT;
+
+	if (nregs != 1)
 		return -EINVAL;
 
 	/*
@@ -615,10 +626,8 @@ static int parse_user_sigframe(struct user_ctxs *user,
 			if (user->fpsimd)
 				goto invalid;
 
-			if (size < sizeof(*user->fpsimd))
-				goto invalid;
-
 			user->fpsimd = (struct fpsimd_context __user *)head;
+			user->fpsimd_size = size;
 			break;
 
 		case ESR_MAGIC:
@@ -632,10 +641,8 @@ static int parse_user_sigframe(struct user_ctxs *user,
 			if (user->sve)
 				goto invalid;
 
-			if (size < sizeof(*user->sve))
-				goto invalid;
-
 			user->sve = (struct sve_context __user *)head;
+			user->sve_size = size;
 			break;
 
 		case TPIDR2_MAGIC:
@@ -645,10 +652,8 @@ static int parse_user_sigframe(struct user_ctxs *user,
 			if (user->tpidr2)
 				goto invalid;
 
-			if (size != sizeof(*user->tpidr2))
-				goto invalid;
-
 			user->tpidr2 = (struct tpidr2_context __user *)head;
+			user->tpidr2_size = size;
 			break;
 
 		case ZA_MAGIC:
@@ -658,10 +663,8 @@ static int parse_user_sigframe(struct user_ctxs *user,
 			if (user->za)
 				goto invalid;
 
-			if (size < sizeof(*user->za))
-				goto invalid;
-
 			user->za = (struct za_context __user *)head;
+			user->za_size = size;
 			break;
 
 		case ZT_MAGIC:
@@ -671,10 +674,8 @@ static int parse_user_sigframe(struct user_ctxs *user,
 			if (user->zt)
 				goto invalid;
 
-			if (size < sizeof(*user->zt))
-				goto invalid;
-
 			user->zt = (struct zt_context __user *)head;
+			user->zt_size = size;
 			break;
 
 		case EXTRA_MAGIC:
@@ -793,7 +794,7 @@ static int restore_sigframe(struct pt_regs *regs,
 		if (user.sve)
 			err = restore_sve_fpsimd_context(&user);
 		else
-			err = restore_fpsimd_context(user.fpsimd);
+			err = restore_fpsimd_context(&user);
 	}
 
 	if (err == 0 && system_supports_sme() && user.tpidr2)