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From:   Kees Cook <keescook@chromium.org>
To:     linux-kernel@vger.kernel.org
Cc:     Kees Cook <keescook@chromium.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Laura Abbott <labbott@redhat.com>,
        Alexander Popov <alex.popov@linux.com>,
        xen-devel@lists.xenproject.org, dri-devel@lists.freedesktop.org,
        intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org,
        netdev@vger.kernel.org, linux-usb@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        dev@openvswitch.org, linux-kbuild@vger.kernel.org,
        linux-security-module@vger.kernel.org,
        kernel-hardening@lists.openwall.com
Subject: [PATCH 1/3] treewide: Lift switch variables out of switches
Date:   Wed, 23 Jan 2019 03:03:47 -0800
Message-Id: <20190123110349.35882-2-keescook@chromium.org>
In-Reply-To: <20190123110349.35882-1-keescook@chromium.org>
References: <20190123110349.35882-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Variables declared in a switch statement before any case statements
cannot be initialized, so move all instances out of the switches.
After this, future always-initialized stack variables will work
and not throw warnings like this:

fs/fcntl.c: In function ‘send_sigio_to_task’:
fs/fcntl.c:738:13: warning: statement will never be executed [-Wswitch-unreachable]
   siginfo_t si;
             ^~

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/xen/enlighten_pv.c                   |  7 ++++---
 drivers/char/pcmcia/cm4000_cs.c               |  2 +-
 drivers/char/ppdev.c                          | 20 ++++++++-----------
 drivers/gpu/drm/drm_edid.c                    |  4 ++--
 drivers/gpu/drm/i915/intel_display.c          |  2 +-
 drivers/gpu/drm/i915/intel_pm.c               |  4 ++--
 drivers/net/ethernet/intel/e1000/e1000_main.c |  3 ++-
 drivers/tty/n_tty.c                           |  3 +--
 drivers/usb/gadget/udc/net2280.c              |  5 ++---
 fs/fcntl.c                                    |  3 ++-
 mm/shmem.c                                    |  5 +++--
 net/core/skbuff.c                             |  4 ++--
 net/ipv6/ip6_gre.c                            |  4 ++--
 net/ipv6/ip6_tunnel.c                         |  4 ++--
 net/openvswitch/flow_netlink.c                |  7 +++----
 security/tomoyo/common.c                      |  3 ++-
 security/tomoyo/condition.c                   |  7 ++++---
 security/tomoyo/util.c                        |  4 ++--
 18 files changed, 45 insertions(+), 46 deletions(-)

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index c54a493e139a..a79d4b548a08 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -907,14 +907,15 @@ static u64 xen_read_msr_safe(unsigned int msr, int *err)
 static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 {
 	int ret;
+#ifdef CONFIG_X86_64
+	unsigned which;
+	u64 base;
+#endif
 
 	ret = 0;
 
 	switch (msr) {
 #ifdef CONFIG_X86_64
-		unsigned which;
-		u64 base;
-
 	case MSR_FS_BASE:		which = SEGBASE_FS; goto set;
 	case MSR_KERNEL_GS_BASE:	which = SEGBASE_GS_USER; goto set;
 	case MSR_GS_BASE:		which = SEGBASE_GS_KERNEL; goto set;
diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index 7a4eb86aedac..7211dc0e6f4f 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -663,6 +663,7 @@ static void monitor_card(struct timer_list *t)
 {
 	struct cm4000_dev *dev = from_timer(dev, t, timer);
 	unsigned int iobase = dev->p_dev->resource[0]->start;
+	unsigned char flags0;
 	unsigned short s;
 	struct ptsreq ptsreq;
 	int i, atrc;
@@ -731,7 +732,6 @@ static void monitor_card(struct timer_list *t)
 	}
 
 	switch (dev->mstate) {
-		unsigned char flags0;
 	case M_CARDOFF:
 		DEBUGP(4, dev, "M_CARDOFF\n");
 		flags0 = inb(REG_FLAGS0(iobase));
diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index 1ae77b41050a..d77c97e4f996 100644
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -359,14 +359,19 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	struct pp_struct *pp = file->private_data;
 	struct parport *port;
 	void __user *argp = (void __user *)arg;
+	struct ieee1284_info *info;
+	unsigned char reg;
+	unsigned char mask;
+	int mode;
+	s32 time32[2];
+	s64 time64[2];
+	struct timespec64 ts;
+	int ret;
 
 	/* First handle the cases that don't take arguments. */
 	switch (cmd) {
 	case PPCLAIM:
 	    {
-		struct ieee1284_info *info;
-		int ret;
-
 		if (pp->flags & PP_CLAIMED) {
 			dev_dbg(&pp->pdev->dev, "you've already got it!\n");
 			return -EINVAL;
@@ -517,15 +522,6 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 	port = pp->pdev->port;
 	switch (cmd) {
-		struct ieee1284_info *info;
-		unsigned char reg;
-		unsigned char mask;
-		int mode;
-		s32 time32[2];
-		s64 time64[2];
-		struct timespec64 ts;
-		int ret;
-
 	case PPRSTATUS:
 		reg = parport_read_status(port);
 		if (copy_to_user(argp, &reg, sizeof(reg)))
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index b506e3622b08..8f93956c1628 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -3942,12 +3942,12 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
 		}
 
 		for_each_cea_db(cea, i, start, end) {
+			int sad_count;
+
 			db = &cea[i];
 			dbl = cea_db_payload_len(db);
 
 			switch (cea_db_tag(db)) {
-				int sad_count;
-
 			case AUDIO_BLOCK:
 				/* Audio Data Block, contains SADs */
 				sad_count = min(dbl / 3, 15 - total_sad_count);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3da9c0f9e948..aa1c2ebea456 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11341,6 +11341,7 @@ static bool check_digital_port_conflicts(struct drm_atomic_state *state)
 	drm_for_each_connector_iter(connector, &conn_iter) {
 		struct drm_connector_state *connector_state;
 		struct intel_encoder *encoder;
+		unsigned int port_mask;
 
 		connector_state = drm_atomic_get_new_connector_state(state, connector);
 		if (!connector_state)
@@ -11354,7 +11355,6 @@ static bool check_digital_port_conflicts(struct drm_atomic_state *state)
 		WARN_ON(!connector_state->crtc);
 
 		switch (encoder->type) {
-			unsigned int port_mask;
 		case INTEL_OUTPUT_DDI:
 			if (WARN_ON(!HAS_DDI(to_i915(dev))))
 				break;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index a26b4eddda25..c135fdec96b3 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -478,9 +478,9 @@ static void vlv_get_fifo_size(struct intel_crtc_state *crtc_state)
 	struct vlv_fifo_state *fifo_state = &crtc_state->wm.vlv.fifo_state;
 	enum pipe pipe = crtc->pipe;
 	int sprite0_start, sprite1_start;
+	uint32_t dsparb, dsparb2, dsparb3;
 
 	switch (pipe) {
-		uint32_t dsparb, dsparb2, dsparb3;
 	case PIPE_A:
 		dsparb = I915_READ(DSPARB);
 		dsparb2 = I915_READ(DSPARB2);
@@ -1944,6 +1944,7 @@ static void vlv_atomic_update_fifo(struct intel_atomic_state *state,
 	const struct vlv_fifo_state *fifo_state =
 		&crtc_state->wm.vlv.fifo_state;
 	int sprite0_start, sprite1_start, fifo_size;
+	uint32_t dsparb, dsparb2, dsparb3;
 
 	if (!crtc_state->fifo_changed)
 		return;
@@ -1969,7 +1970,6 @@ static void vlv_atomic_update_fifo(struct intel_atomic_state *state,
 	spin_lock(&dev_priv->uncore.lock);
 
 	switch (crtc->pipe) {
-		uint32_t dsparb, dsparb2, dsparb3;
 	case PIPE_A:
 		dsparb = I915_READ_FW(DSPARB);
 		dsparb2 = I915_READ_FW(DSPARB2);
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 8fe9af0e2ab7..041062736845 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -3140,8 +3140,9 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
 
 		hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
 		if (skb->data_len && hdr_len == len) {
+			unsigned int pull_size;
+
 			switch (hw->mac_type) {
-				unsigned int pull_size;
 			case e1000_82544:
 				/* Make sure we have room to chop off 4 bytes,
 				 * and that the end alignment will work out to
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 5dc9686697cf..eafb39157281 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -634,6 +634,7 @@ static size_t __process_echoes(struct tty_struct *tty)
 	while (MASK(ldata->echo_commit) != MASK(tail)) {
 		c = echo_buf(ldata, tail);
 		if (c == ECHO_OP_START) {
+			unsigned int num_chars, num_bs;
 			unsigned char op;
 			int no_space_left = 0;
 
@@ -652,8 +653,6 @@ static size_t __process_echoes(struct tty_struct *tty)
 			op = echo_buf(ldata, tail + 1);
 
 			switch (op) {
-				unsigned int num_chars, num_bs;
-
 			case ECHO_OP_ERASE_TAB:
 				if (MASK(ldata->echo_commit) == MASK(tail + 2))
 					goto not_yet_stored;
diff --git a/drivers/usb/gadget/udc/net2280.c b/drivers/usb/gadget/udc/net2280.c
index e7dae5379e04..2b275a574e94 100644
--- a/drivers/usb/gadget/udc/net2280.c
+++ b/drivers/usb/gadget/udc/net2280.c
@@ -2854,16 +2854,15 @@ static void ep_clear_seqnum(struct net2280_ep *ep)
 static void handle_stat0_irqs_superspeed(struct net2280 *dev,
 		struct net2280_ep *ep, struct usb_ctrlrequest r)
 {
+	struct net2280_ep *e;
 	int tmp = 0;
+	u16 status;
 
 #define	w_value		le16_to_cpu(r.wValue)
 #define	w_index		le16_to_cpu(r.wIndex)
 #define	w_length	le16_to_cpu(r.wLength)
 
 	switch (r.bRequest) {
-		struct net2280_ep *e;
-		u16 status;
-
 	case USB_REQ_SET_CONFIGURATION:
 		dev->addressed_state = !w_value;
 		goto usb3_delegate;
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 083185174c6d..0640b64ecdc2 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -725,6 +725,8 @@ static void send_sigio_to_task(struct task_struct *p,
 			       struct fown_struct *fown,
 			       int fd, int reason, enum pid_type type)
 {
+	kernel_siginfo_t si;
+
 	/*
 	 * F_SETSIG can change ->signum lockless in parallel, make
 	 * sure we read it once and use the same value throughout.
@@ -735,7 +737,6 @@ static void send_sigio_to_task(struct task_struct *p,
 		return;
 
 	switch (signum) {
-		kernel_siginfo_t si;
 		default:
 			/* Queue a rt signal with the appropriate fd as its
 			   value.  We use SI_SIGIO as the source, not 
diff --git a/mm/shmem.c b/mm/shmem.c
index 6ece1e2fe76e..0b02624dd8b2 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1721,6 +1721,9 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
 		swap_free(swap);
 
 	} else {
+		loff_t i_size;
+		pgoff_t off;
+
 		if (vma && userfaultfd_missing(vma)) {
 			*fault_type = handle_userfault(vmf, VM_UFFD_MISSING);
 			return 0;
@@ -1734,8 +1737,6 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
 		if (shmem_huge == SHMEM_HUGE_FORCE)
 			goto alloc_huge;
 		switch (sbinfo->huge) {
-			loff_t i_size;
-			pgoff_t off;
 		case SHMEM_HUGE_NEVER:
 			goto alloc_nohuge;
 		case SHMEM_HUGE_WITHIN_SIZE:
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 26d848484912..7597b3fc9d21 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4506,9 +4506,9 @@ static __sum16 *skb_checksum_setup_ip(struct sk_buff *skb,
 				      typeof(IPPROTO_IP) proto,
 				      unsigned int off)
 {
-	switch (proto) {
-		int err;
+	int err;
 
+	switch (proto) {
 	case IPPROTO_TCP:
 		err = skb_maybe_pull_tail(skb, off + sizeof(struct tcphdr),
 					  off + MAX_TCP_HDR_LEN);
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index b1be67ca6768..9aee1add46c0 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -427,9 +427,11 @@ static int ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		       u8 type, u8 code, int offset, __be32 info)
 {
 	struct net *net = dev_net(skb->dev);
+	struct ipv6_tlv_tnl_enc_lim *tel;
 	const struct ipv6hdr *ipv6h;
 	struct tnl_ptk_info tpi;
 	struct ip6_tnl *t;
+	__u32 teli;
 
 	if (gre_parse_header(skb, &tpi, NULL, htons(ETH_P_IPV6),
 			     offset) < 0)
@@ -442,8 +444,6 @@ static int ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 		return -ENOENT;
 
 	switch (type) {
-		struct ipv6_tlv_tnl_enc_lim *tel;
-		__u32 teli;
 	case ICMPV6_DEST_UNREACH:
 		net_dbg_ratelimited("%s: Path to destination invalid or inactive!\n",
 				    t->parms.name);
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 0c6403cf8b52..94ccc7a9037b 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -478,10 +478,12 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 	struct net *net = dev_net(skb->dev);
 	u8 rel_type = ICMPV6_DEST_UNREACH;
 	u8 rel_code = ICMPV6_ADDR_UNREACH;
+	struct ipv6_tlv_tnl_enc_lim *tel;
 	__u32 rel_info = 0;
 	struct ip6_tnl *t;
 	int err = -ENOENT;
 	int rel_msg = 0;
+	__u32 mtu, teli;
 	u8 tproto;
 	__u16 len;
 
@@ -501,8 +503,6 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
 	err = 0;
 
 	switch (*type) {
-		struct ipv6_tlv_tnl_enc_lim *tel;
-		__u32 mtu, teli;
 	case ICMPV6_DEST_UNREACH:
 		net_dbg_ratelimited("%s: Path to destination invalid or inactive!\n",
 				    t->parms.name);
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index 691da853bef5..dee2f9516ae8 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -2652,8 +2652,11 @@ static int validate_set(const struct nlattr *a,
 			u8 mac_proto, __be16 eth_type, bool masked, bool log)
 {
 	const struct nlattr *ovs_key = nla_data(a);
+	const struct ovs_key_ipv4 *ipv4_key;
+	const struct ovs_key_ipv6 *ipv6_key;
 	int key_type = nla_type(ovs_key);
 	size_t key_len;
+	int err;
 
 	/* There can be only one key in a action */
 	if (nla_total_size(nla_len(ovs_key)) != nla_len(a))
@@ -2671,10 +2674,6 @@ static int validate_set(const struct nlattr *a,
 		return -EINVAL;
 
 	switch (key_type) {
-	const struct ovs_key_ipv4 *ipv4_key;
-	const struct ovs_key_ipv6 *ipv6_key;
-	int err;
-
 	case OVS_KEY_ATTR_PRIORITY:
 	case OVS_KEY_ATTR_SKB_MARK:
 	case OVS_KEY_ATTR_CT_MARK:
diff --git a/security/tomoyo/common.c b/security/tomoyo/common.c
index c598aa00d5e3..bedbd0518153 100644
--- a/security/tomoyo/common.c
+++ b/security/tomoyo/common.c
@@ -1583,8 +1583,9 @@ static void tomoyo_read_domain(struct tomoyo_io_buffer *head)
 	list_for_each_cookie(head->r.domain, &tomoyo_domain_list) {
 		struct tomoyo_domain_info *domain =
 			list_entry(head->r.domain, typeof(*domain), list);
+		u8 i;
+
 		switch (head->r.step) {
-			u8 i;
 		case 0:
 			if (domain->is_deleted &&
 			    !head->r.print_this_domain_only)
diff --git a/security/tomoyo/condition.c b/security/tomoyo/condition.c
index 8d0e1b9c9c57..c10d903febe5 100644
--- a/security/tomoyo/condition.c
+++ b/security/tomoyo/condition.c
@@ -787,10 +787,11 @@ bool tomoyo_condition(struct tomoyo_request_info *r,
 		/* Check string expressions. */
 		if (right == TOMOYO_NAME_UNION) {
 			const struct tomoyo_name_union *ptr = names_p++;
+			struct tomoyo_path_info *symlink;
+			struct tomoyo_execve *ee;
+			struct file *file;
+
 			switch (left) {
-				struct tomoyo_path_info *symlink;
-				struct tomoyo_execve *ee;
-				struct file *file;
 			case TOMOYO_SYMLINK_TARGET:
 				symlink = obj ? obj->symlink_target : NULL;
 				if (!symlink ||
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c
index badffc8271c8..8e2bb36df37b 100644
--- a/security/tomoyo/util.c
+++ b/security/tomoyo/util.c
@@ -668,6 +668,8 @@ static bool tomoyo_file_matches_pattern2(const char *filename,
 {
 	while (filename < filename_end && pattern < pattern_end) {
 		char c;
+		int i, j;
+
 		if (*pattern != '\\') {
 			if (*filename++ != *pattern++)
 				return false;
@@ -676,8 +678,6 @@ static bool tomoyo_file_matches_pattern2(const char *filename,
 		c = *filename;
 		pattern++;
 		switch (*pattern) {
-			int i;
-			int j;
 		case '?':
 			if (c == '/') {
 				return false;
-- 
2.17.1