Merge 4.9.25 into android-4.9

Changes in 4.9.25: KEYS: Disallow keyrings beginning with '.' to be joined as session keyrings KEYS: Change the name of the dead type to ".dead" to prevent user access KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings tracing: Allocate the snapshot buffer before enabling probe ring-buffer: Have ring_buffer_iter_empty() return true when empty mm: prevent NR_ISOLATE_* stats from going negative cifs: Do not send echoes before Negotiate is complete CIFS: remove bad_network_name flag s390/mm: fix CMMA vs KSM vs others Input: elantech - add Fujitsu Lifebook E547 to force crc_enabled ACPI / power: Avoid maybe-uninitialized warning mmc: sdhci-esdhc-imx: increase the pad I/O drive strength for DDR50 card ubifs: Fix RENAME_WHITEOUT support ubifs: Fix O_TMPFILE corner case in ubifs_link() mac80211: reject ToDS broadcast data frames mac80211: fix MU-MIMO follow-MAC mode ubi/upd: Always flush after prepared for an update powerpc/kprobe: Fix oops when kprobed on 'stdu' instruction x86/mce/AMD: Give a name to MCA bank 3 when accessed with legacy MSRs x86/mce: Make the MCE notifier a blocking one device-dax: switch to srcu, fix rcu_read_lock() vs pte allocation Linux 4.9.25 Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
2026-06-06 19:08:57 +09:00 · 2017-04-27 10:09:21 +02:00
parent 5b9202d62b a8c90ef622
commit bae751b9ab
24 changed files with 178 additions and 90 deletions
--- a/2
+++ b/2
@@ -1,6 +1,6 @@
 VERSION = 4
 PATCHLEVEL = 9
-SUBLEVEL = 24
+SUBLEVEL = 25
 EXTRAVERSION =
 NAME = Roaring Lionus

--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -689,7 +689,7 @@ resume_kernel:

 	addi	r8,r1,INT_FRAME_SIZE	/* Get the kprobed function entry */

-	lwz	r3,GPR1(r1)
+	ld	r3,GPR1(r1)
 	subi	r3,r3,INT_FRAME_SIZE	/* dst: Allocate a trampoline exception frame */
 	mr	r4,r1			/* src:  current exception frame */
 	mr	r1,r3			/* Reroute the trampoline frame to r1 */
@@ -703,8 +703,8 @@ resume_kernel:
 	addi	r6,r6,8
 	bdnz	2b

-	/* Do real store operation to complete stwu */
-	lwz	r5,GPR1(r1)
+	/* Do real store operation to complete stdu */
+	ld	r5,GPR1(r1)
 	std	r8,0(r5)

 	/* Clear _TIF_EMULATE_STACK_STORE flag */
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1029,6 +1029,8 @@ int get_guest_storage_key(struct mm_struct *mm, unsigned long addr,
 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 			      pte_t *ptep, pte_t entry)
 {
+	if (pte_present(entry))
+		pte_val(entry) &= ~_PAGE_UNUSED;
 	if (mm_has_pgste(mm))
 		ptep_set_pte_at(mm, addr, ptep, entry);
 	else
--- a/arch/x86/kernel/cpu/mcheck/mce-genpool.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-genpool.c
@@ -85,7 +85,7 @@ void mce_gen_pool_process(void)
 	head = llist_reverse_order(head);
 	llist_for_each_entry_safe(node, tmp, head, llnode) {
 		mce = &node->mce;
-		atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
+		blocking_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
 		gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
 	}
 }
--- a/arch/x86/kernel/cpu/mcheck/mce-internal.h
+++ b/arch/x86/kernel/cpu/mcheck/mce-internal.h
@@ -13,7 +13,7 @@ enum severity_level {
 	MCE_PANIC_SEVERITY,
 };

-extern struct atomic_notifier_head x86_mce_decoder_chain;
+extern struct blocking_notifier_head x86_mce_decoder_chain;

 #define ATTR_LEN		16
 #define INITIAL_CHECK_INTERVAL	5 * 60 /* 5 minutes */
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -120,7 +120,7 @@ static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs);
 * CPU/chipset specific EDAC code can register a notifier call here to print
 * MCE errors in a human-readable form.
 */
-ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
+BLOCKING_NOTIFIER_HEAD(x86_mce_decoder_chain);

 /* Do initial initialization of a struct mce */
 void mce_setup(struct mce *m)
@@ -213,13 +213,13 @@ void mce_register_decode_chain(struct notifier_block *nb)
 	if (nb != &mce_srao_nb && nb->priority == INT_MAX)
 		nb->priority -= 1;

-	atomic_notifier_chain_register(&x86_mce_decoder_chain, nb);
+	blocking_notifier_chain_register(&x86_mce_decoder_chain, nb);
 }
 EXPORT_SYMBOL_GPL(mce_register_decode_chain);

 void mce_unregister_decode_chain(struct notifier_block *nb)
 {
-	atomic_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
+	blocking_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
 }
 EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);

@@ -272,8 +272,6 @@ struct mca_msr_regs msr_ops = {

 static void print_mce(struct mce *m)
 {
-	int ret = 0;
-
 	pr_emerg(HW_ERR "CPU %d: Machine Check Exception: %Lx Bank %d: %016Lx\n",
 	       m->extcpu, m->mcgstatus, m->bank, m->status);

@@ -309,14 +307,6 @@ static void print_mce(struct mce *m)
 		m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid,
 		cpu_data(m->extcpu).microcode);

-	/*
-	 * Print out human-readable details about the MCE error,
-	 * (if the CPU has an implementation for that)
-	 */
-	ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
-	if (ret == NOTIFY_STOP)
-		return;
-
 	pr_emerg_ratelimited(HW_ERR "Run the above through 'mcelog --ascii'\n");
 }

--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -59,7 +59,7 @@ static const char * const th_names[] = {
 	"load_store",
 	"insn_fetch",
 	"combined_unit",
-	"",
+	"decode_unit",
 	"northbridge",
 	"execution_unit",
 };
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -200,6 +200,7 @@ static int acpi_power_get_list_state(struct list_head *list, int *state)
 		return -EINVAL;

 	/* The state of the list is 'on' IFF all resources are 'on'. */
+	cur_state = 0;
 	list_for_each_entry(entry, list, node) {
 		struct acpi_power_resource *resource = entry->resource;
 		acpi_handle handle = resource->device.handle;
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -2,6 +2,7 @@ menuconfig DEV_DAX
 	tristate "DAX: direct access to differentiated memory"
 	default m if NVDIMM_DAX
 	depends on TRANSPARENT_HUGEPAGE
+	select SRCU
 	help
 	  Support raw access to differentiated (persistence, bandwidth,
 	  latency...) memory via an mmap(2) capable character
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -24,6 +24,7 @@
 #include "dax.h"

 static dev_t dax_devt;
+DEFINE_STATIC_SRCU(dax_srcu);
 static struct class *dax_class;
 static DEFINE_IDA(dax_minor_ida);
 static int nr_dax = CONFIG_NR_DEV_DAX;
@@ -59,7 +60,7 @@ struct dax_region {
 * @region - parent region
 * @dev - device backing the character device
 * @cdev - core chardev data
- * @alive - !alive + rcu grace period == no new mappings can be established
+ * @alive - !alive + srcu grace period == no new mappings can be established
 * @id - child id in the region
 * @num_resources - number of physical address extents in this device
 * @res - array of physical address ranges
@@ -437,7 +438,7 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev,
 static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
 		pmd_t *pmd, unsigned int flags)
 {
-	int rc;
+	int rc, id;
 	struct file *filp = vma->vm_file;
 	struct dax_dev *dax_dev = filp->private_data;

@@ -445,9 +446,9 @@ static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr,
 			current->comm, (flags & FAULT_FLAG_WRITE)
 			? "write" : "read", vma->vm_start, vma->vm_end);

-	rcu_read_lock();
+	id = srcu_read_lock(&dax_srcu);
 	rc = __dax_dev_pmd_fault(dax_dev, vma, addr, pmd, flags);
-	rcu_read_unlock();
+	srcu_read_unlock(&dax_srcu, id);

 	return rc;
 }
@@ -563,11 +564,11 @@ static void unregister_dax_dev(void *dev)
 	 * Note, rcu is not protecting the liveness of dax_dev, rcu is
 	 * ensuring that any fault handlers that might have seen
 	 * dax_dev->alive == true, have completed.  Any fault handlers
-	 * that start after synchronize_rcu() has started will abort
+	 * that start after synchronize_srcu() has started will abort
 	 * upon seeing dax_dev->alive == false.
 	 */
 	dax_dev->alive = false;
-	synchronize_rcu();
+	synchronize_srcu(&dax_srcu);
 	unmap_mapping_range(dax_dev->inode->i_mapping, 0, 0, 1);
 	cdev_del(cdev);
 	device_unregister(dev);
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c
@@ -1118,6 +1118,7 @@ static int elantech_get_resolution_v4(struct psmouse *psmouse,
 * Asus UX32VD             0x361f02        00, 15, 0e      clickpad
 * Avatar AVIU-145A2       0x361f00        ?               clickpad
 * Fujitsu LIFEBOOK E544   0x470f00        d0, 12, 09      2 hw buttons
+ * Fujitsu LIFEBOOK E547   0x470f00        50, 12, 09      2 hw buttons
 * Fujitsu LIFEBOOK E554   0x570f01        40, 14, 0c      2 hw buttons
 * Fujitsu T725            0x470f01        05, 12, 09      2 hw buttons
 * Fujitsu H730            0x570f00        c0, 14, 0c      3 hw buttons (**)
@@ -1523,6 +1524,13 @@ static const struct dmi_system_id elantech_dmi_force_crc_enabled[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E544"),
 		},
 	},
+	{
+		/* Fujitsu LIFEBOOK E547 does not work with crc_enabled == 0 */
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E547"),
+		},
+	},
 	{
 		/* Fujitsu LIFEBOOK E554  does not work with crc_enabled == 0 */
 		.matches = {
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -830,6 +830,7 @@ static int esdhc_change_pinstate(struct sdhci_host *host,

 	switch (uhs) {
 	case MMC_TIMING_UHS_SDR50:
+	case MMC_TIMING_UHS_DDR50:
 		pinctrl = imx_data->pins_100mhz;
 		break;
 	case MMC_TIMING_UHS_SDR104:
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -148,11 +148,11 @@ int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
 			return err;
 	}

-	if (bytes == 0) {
-		err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
-		if (err)
-			return err;
+	err = ubi_wl_flush(ubi, UBI_ALL, UBI_ALL);
+	if (err)
+		return err;

+	if (bytes == 0) {
 		err = clear_update_marker(ubi, vol, 0);
 		if (err)
 			return err;
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -930,7 +930,6 @@ struct cifs_tcon {
 	bool use_persistent:1; /* use persistent instead of durable handles */
 #ifdef CONFIG_CIFS_SMB2
 	bool print:1;		/* set if connection to printer share */
-	bool bad_network_name:1; /* set if ret status STATUS_BAD_NETWORK_NAME */
 	__le32 capabilities;
 	__u32 share_flags;
 	__u32 maximal_access;
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -1015,6 +1015,15 @@ cifs_dir_needs_close(struct cifsFileInfo *cfile)
 	return !cfile->srch_inf.endOfSearch && !cfile->invalidHandle;
 }

+static bool
+cifs_can_echo(struct TCP_Server_Info *server)
+{
+	if (server->tcpStatus == CifsGood)
+		return true;
+
+	return false;
+}
+
 struct smb_version_operations smb1_operations = {
 	.send_cancel = send_nt_cancel,
 	.compare_fids = cifs_compare_fids,
@@ -1049,6 +1058,7 @@ struct smb_version_operations smb1_operations = {
 	.get_dfs_refer = CIFSGetDFSRefer,
 	.qfs_tcon = cifs_qfs_tcon,
 	.is_path_accessible = cifs_is_path_accessible,
+	.can_echo = cifs_can_echo,
 	.query_path_info = cifs_query_path_info,
 	.query_file_info = cifs_query_file_info,
 	.get_srv_inum = cifs_get_srv_inum,
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1084,9 +1084,6 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	else
 		return -EIO;

-	if (tcon && tcon->bad_network_name)
-		return -ENOENT;
-
 	if ((tcon && tcon->seal) &&
 	    ((ses->server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION) == 0)) {
 		cifs_dbg(VFS, "encryption requested but no server support");
@@ -1188,8 +1185,6 @@ tcon_exit:
 tcon_error_exit:
 	if (rsp->hdr.Status == STATUS_BAD_NETWORK_NAME) {
 		cifs_dbg(VFS, "BAD_NETWORK_NAME: %s\n", tree);
-		if (tcon)
-			tcon->bad_network_name = true;
 	}
 	goto tcon_exit;
 }
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -622,6 +622,11 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
 		return err;

 	lock_2_inodes(dir, inode);
+
+	/* Handle O_TMPFILE corner case, it is allowed to link a O_TMPFILE. */
+	if (inode->i_nlink == 0)
+		ubifs_delete_orphan(c, inode->i_ino);
+
 	inc_nlink(inode);
 	ihold(inode);
 	inode->i_ctime = ubifs_current_time(inode);
@@ -641,6 +646,8 @@ out_cancel:
 	dir->i_size -= sz_change;
 	dir_ui->ui_size = dir->i_size;
 	drop_nlink(inode);
+	if (inode->i_nlink == 0)
+		ubifs_add_orphan(c, inode->i_ino);
 	unlock_2_inodes(dir, inode);
 	ubifs_release_budget(c, &req);
 	iput(inode);
@@ -1088,9 +1095,6 @@ static int do_rename(struct inode *old_dir, struct dentry *old_dentry,
 	struct timespec time;
 	unsigned int uninitialized_var(saved_nlink);

-	if (flags & ~RENAME_NOREPLACE)
-		return -EINVAL;
-
 	/*
 	 * Budget request settings: deletion direntry, new direntry, removing
 	 * the old inode, and changing old and new parent directory inodes.
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3435,11 +3435,23 @@ EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
 int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
+	struct buffer_page *reader;
+	struct buffer_page *head_page;
+	struct buffer_page *commit_page;
+	unsigned commit;

 	cpu_buffer = iter->cpu_buffer;

-	return iter->head_page == cpu_buffer->commit_page &&
-		iter->head == rb_commit_index(cpu_buffer);
+	/* Remember, trace recording is off when iterator is in use */
+	reader = cpu_buffer->reader_page;
+	head_page = cpu_buffer->head_page;
+	commit_page = cpu_buffer->commit_page;
+	commit = rb_page_commit(commit_page);
+
+	return ((iter->head_page == commit_page && iter->head == commit) ||
+		(iter->head_page == reader && commit_page == head_page &&
+		 head_page->read == commit &&
+		 iter->head == rb_page_commit(cpu_buffer->reader_page)));
 }
 EXPORT_SYMBOL_GPL(ring_buffer_iter_empty);

--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6571,11 +6571,13 @@ ftrace_trace_snapshot_callback(struct ftrace_hash *hash,
 		return ret;

 out_reg:
+	ret = alloc_snapshot(&global_trace);
+	if (ret < 0)
+		goto out;
+
 	ret = register_ftrace_function_probe(glob, ops, count);

-	if (ret >= 0)
-		alloc_snapshot(&global_trace);
-
+ out:
 	return ret < 0 ? ret : 0;
 }

--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -183,9 +183,9 @@ void putback_movable_pages(struct list_head *l)
 			unlock_page(page);
 			put_page(page);
 		} else {
-			putback_lru_page(page);
 			dec_node_page_state(page, NR_ISOLATED_ANON +
 					page_is_file_cache(page));
+			putback_lru_page(page);
 		}
 	}
 }
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -208,6 +208,51 @@ ieee80211_rx_radiotap_hdrlen(struct ieee80211_local *local,
 	return len;
 }

+static void ieee80211_handle_mu_mimo_mon(struct ieee80211_sub_if_data *sdata,
+					 struct sk_buff *skb,
+					 int rtap_vendor_space)
+{
+	struct {
+		struct ieee80211_hdr_3addr hdr;
+		u8 category;
+		u8 action_code;
+	} __packed action;
+
+	if (!sdata)
+		return;
+
+	BUILD_BUG_ON(sizeof(action) != IEEE80211_MIN_ACTION_SIZE + 1);
+
+	if (skb->len < rtap_vendor_space + sizeof(action) +
+		       VHT_MUMIMO_GROUPS_DATA_LEN)
+		return;
+
+	if (!is_valid_ether_addr(sdata->u.mntr.mu_follow_addr))
+		return;
+
+	skb_copy_bits(skb, rtap_vendor_space, &action, sizeof(action));
+
+	if (!ieee80211_is_action(action.hdr.frame_control))
+		return;
+
+	if (action.category != WLAN_CATEGORY_VHT)
+		return;
+
+	if (action.action_code != WLAN_VHT_ACTION_GROUPID_MGMT)
+		return;
+
+	if (!ether_addr_equal(action.hdr.addr1, sdata->u.mntr.mu_follow_addr))
+		return;
+
+	skb = skb_copy(skb, GFP_ATOMIC);
+	if (!skb)
+		return;
+
+	skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
+	skb_queue_tail(&sdata->skb_queue, skb);
+	ieee80211_queue_work(&sdata->local->hw, &sdata->work);
+}
+
 /*
 * ieee80211_add_rx_radiotap_header - add radiotap header
 *
@@ -515,7 +560,6 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 	struct net_device *prev_dev = NULL;
 	int present_fcs_len = 0;
 	unsigned int rtap_vendor_space = 0;
-	struct ieee80211_mgmt *mgmt;
 	struct ieee80211_sub_if_data *monitor_sdata =
 		rcu_dereference(local->monitor_sdata);

@@ -553,6 +597,8 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 		return remove_monitor_info(local, origskb, rtap_vendor_space);
 	}

+	ieee80211_handle_mu_mimo_mon(monitor_sdata, origskb, rtap_vendor_space);
+
 	/* room for the radiotap header based on driver features */
 	rt_hdrlen = ieee80211_rx_radiotap_hdrlen(local, status, origskb);
 	needed_headroom = rt_hdrlen - rtap_vendor_space;
@@ -618,23 +664,6 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 		ieee80211_rx_stats(sdata->dev, skb->len);
 	}

-	mgmt = (void *)skb->data;
-	if (monitor_sdata &&
-	    skb->len >= IEEE80211_MIN_ACTION_SIZE + 1 + VHT_MUMIMO_GROUPS_DATA_LEN &&
-	    ieee80211_is_action(mgmt->frame_control) &&
-	    mgmt->u.action.category == WLAN_CATEGORY_VHT &&
-	    mgmt->u.action.u.vht_group_notif.action_code == WLAN_VHT_ACTION_GROUPID_MGMT &&
-	    is_valid_ether_addr(monitor_sdata->u.mntr.mu_follow_addr) &&
-	    ether_addr_equal(mgmt->da, monitor_sdata->u.mntr.mu_follow_addr)) {
-		struct sk_buff *mu_skb = skb_copy(skb, GFP_ATOMIC);
-
-		if (mu_skb) {
-			mu_skb->pkt_type = IEEE80211_SDATA_QUEUE_TYPE_FRAME;
-			skb_queue_tail(&monitor_sdata->skb_queue, mu_skb);
-			ieee80211_queue_work(&local->hw, &monitor_sdata->work);
-		}
-	}
-
 	if (prev_dev) {
 		skb->dev = prev_dev;
 		netif_receive_skb(skb);
@@ -3617,6 +3646,27 @@ static bool ieee80211_accept_frame(struct ieee80211_rx_data *rx)
 			    !ether_addr_equal(bssid, hdr->addr1))
 				return false;
 		}
+
+		/*
+		 * 802.11-2016 Table 9-26 says that for data frames, A1 must be
+		 * the BSSID - we've checked that already but may have accepted
+		 * the wildcard (ff:ff:ff:ff:ff:ff).
+		 *
+		 * It also says:
+		 *	The BSSID of the Data frame is determined as follows:
+		 *	a) If the STA is contained within an AP or is associated
+		 *	   with an AP, the BSSID is the address currently in use
+		 *	   by the STA contained in the AP.
+		 *
+		 * So we should not accept data frames with an address that's
+		 * multicast.
+		 *
+		 * Accepting it also opens a security problem because stations
+		 * could encrypt it with the GTK and inject traffic that way.
+		 */
+		if (ieee80211_is_data(hdr->frame_control) && multicast)
+			return false;
+
 		return true;
 	case NL80211_IFTYPE_WDS:
 		if (bssid || !ieee80211_is_data(hdr->frame_control))
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -46,7 +46,7 @@ static unsigned long key_gc_flags;
 * immediately unlinked.
 */
 struct key_type key_type_dead = {
-	.name = "dead",
+	.name = ".dead",
 };

 /*
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -271,7 +271,8 @@ error:
 * Create and join an anonymous session keyring or join a named session
 * keyring, creating it if necessary.  A named session keyring must have Search
 * permission for it to be joined.  Session keyrings without this permit will
- * be skipped over.
+ * be skipped over.  It is not permitted for userspace to create or join
+ * keyrings whose name begin with a dot.
 *
 * If successful, the ID of the joined session keyring will be returned.
 */
@@ -288,12 +289,16 @@ long keyctl_join_session_keyring(const char __user *_name)
 			ret = PTR_ERR(name);
 			goto error;
 		}
+
+		ret = -EPERM;
+		if (name[0] == '.')
+			goto error_name;
 	}

 	/* join the session */
 	ret = join_session_keyring(name);
+error_name:
 	kfree(name);
-
 error:
 	return ret;
 }
@@ -1251,8 +1256,8 @@ error:
 * Read or set the default keyring in which request_key() will cache keys and
 * return the old setting.
 *
- * If a process keyring is specified then this will be created if it doesn't
- * yet exist.  The old setting will be returned if successful.
+ * If a thread or process keyring is specified then it will be created if it
+ * doesn't yet exist.  The old setting will be returned if successful.
 */
 long keyctl_set_reqkey_keyring(int reqkey_defl)
 {
@@ -1277,11 +1282,8 @@ long keyctl_set_reqkey_keyring(int reqkey_defl)

 	case KEY_REQKEY_DEFL_PROCESS_KEYRING:
 		ret = install_process_keyring_to_cred(new);
-		if (ret < 0) {
-			if (ret != -EEXIST)
-				goto error;
-			ret = 0;
-		}
+		if (ret < 0)
+			goto error;
 		goto set;

 	case KEY_REQKEY_DEFL_DEFAULT:
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -127,13 +127,18 @@ error:
 }

 /*
- * Install a fresh thread keyring directly to new credentials.  This keyring is
- * allowed to overrun the quota.
+ * Install a thread keyring to the given credentials struct if it didn't have
+ * one already.  This is allowed to overrun the quota.
+ *
+ * Return: 0 if a thread keyring is now present; -errno on failure.
 */
 int install_thread_keyring_to_cred(struct cred *new)
 {
 	struct key *keyring;

+	if (new->thread_keyring)
+		return 0;
+
 	keyring = keyring_alloc("_tid", new->uid, new->gid, new,
 				KEY_POS_ALL | KEY_USR_VIEW,
 				KEY_ALLOC_QUOTA_OVERRUN,
@@ -146,7 +151,9 @@ int install_thread_keyring_to_cred(struct cred *new)
 }

 /*
- * Install a fresh thread keyring, discarding the old one.
+ * Install a thread keyring to the current task if it didn't have one already.
+ *
+ * Return: 0 if a thread keyring is now present; -errno on failure.
 */
 static int install_thread_keyring(void)
 {
@@ -157,8 +164,6 @@ static int install_thread_keyring(void)
 	if (!new)
 		return -ENOMEM;

-	BUG_ON(new->thread_keyring);
-
 	ret = install_thread_keyring_to_cred(new);
 	if (ret < 0) {
 		abort_creds(new);
@@ -169,17 +174,17 @@ static int install_thread_keyring(void)
 }

 /*
- * Install a process keyring directly to a credentials struct.
+ * Install a process keyring to the given credentials struct if it didn't have
+ * one already.  This is allowed to overrun the quota.
 *
- * Returns -EEXIST if there was already a process keyring, 0 if one installed,
- * and other value on any other error
+ * Return: 0 if a process keyring is now present; -errno on failure.
 */
 int install_process_keyring_to_cred(struct cred *new)
 {
 	struct key *keyring;

 	if (new->process_keyring)
-		return -EEXIST;
+		return 0;

 	keyring = keyring_alloc("_pid", new->uid, new->gid, new,
 				KEY_POS_ALL | KEY_USR_VIEW,
@@ -193,11 +198,9 @@ int install_process_keyring_to_cred(struct cred *new)
 }

 /*
- * Make sure a process keyring is installed for the current process.  The
- * existing process keyring is not replaced.
+ * Install a process keyring to the current task if it didn't have one already.
 *
- * Returns 0 if there is a process keyring by the end of this function, some
- * error otherwise.
+ * Return: 0 if a process keyring is now present; -errno on failure.
 */
 static int install_process_keyring(void)
 {
@@ -211,14 +214,18 @@ static int install_process_keyring(void)
 	ret = install_process_keyring_to_cred(new);
 	if (ret < 0) {
 		abort_creds(new);
-		return ret != -EEXIST ? ret : 0;
+		return ret;
 	}

 	return commit_creds(new);
 }

 /*
- * Install a session keyring directly to a credentials struct.
+ * Install the given keyring as the session keyring of the given credentials
+ * struct, replacing the existing one if any.  If the given keyring is NULL,
+ * then install a new anonymous session keyring.
+ *
+ * Return: 0 on success; -errno on failure.
 */
 int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
 {
@@ -253,8 +260,11 @@ int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
 }

 /*
- * Install a session keyring, discarding the old one.  If a keyring is not
- * supplied, an empty one is invented.
+ * Install the given keyring as the session keyring of the current task,
+ * replacing the existing one if any.  If the given keyring is NULL, then
+ * install a new anonymous session keyring.
+ *
+ * Return: 0 on success; -errno on failure.
 */
 static int install_session_keyring(struct key *keyring)
 {