[PATCH 0/3] firewire: fixes for kernel v4.9 or later

[PATCH 0/3] firewire: fixes for kernel v4.9 or later

[Takashi Sakamoto]

Hi,

This patchset respins patches posted before to fix some bugs for Linux
FireWire subsystem. I expect them to be sent to Linus via pull request
by maintainer of Linux sound subsystem since the path appears to be
available after a short conversation with the maintainer. This patchset
is expected to be applied to 'for-linus' branch for v5.18 kernel, and
to stable kernels based on v4.9 or later.

This patchset includes below patches:

* [PATCH V2] drivers/firewire: use struct_size over open coded arithmetic
    * https://lore.kernel.org/lkml/20220210060805.1608198-1-chi.minghao@zte.com.cn/
* [PATCH] firewire: core: extend card->lock in fw_core_handle_bus_reset
    * https://lore.kernel.org/lkml/20220303183038.54126-1-dossche.niels@gmail.com/
* [PATCH] firewire: remove check of list iterator against head past the loop body
    * https://lore.kernel.org/lkml/20220331223601.902329-1-jakobkoschel@gmail.com/

Chengfeng Ye (1):
  firewire: fix potential uaf in outbound_phy_packet_callback()

Jakob Koschel (1):
  firewire: remove check of list iterator against head past the loop
    body

Niels Dossche (1):
  firewire: core: extend card->lock in fw_core_handle_bus_reset

 drivers/firewire/core-card.c        |  3 +++
 drivers/firewire/core-cdev.c        |  4 +++-
 drivers/firewire/core-topology.c    |  9 +++------
 drivers/firewire/core-transaction.c | 30 +++++++++++++++--------------
 drivers/firewire/sbp2.c             | 13 +++++++------
 5 files changed, 32 insertions(+), 27 deletions(-)

-- 
2.34.1

[PATCH 1/3] firewire: fix potential uaf in outbound_phy_packet_callback()

[Takashi Sakamoto]

From: Chengfeng Ye <cyeaa@connect.ust.hk>

&e->event and e point to the same address, and &e->event could
be freed in queue_event. So there is a potential uaf issue if
we dereference e after calling queue_event(). Fix this by adding
a temporary variable to maintain e->client in advance, this can
avoid the potential uaf issue.

Cc: <stable@vger.kernel.org>
Signed-off-by: Chengfeng Ye <cyeaa@connect.ust.hk>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 drivers/firewire/core-cdev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 9f89c17730b1..708e417200f4 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -1500,6 +1500,7 @@ static void outbound_phy_packet_callback(struct fw_packet *packet,
 {
 	struct outbound_phy_packet_event *e =
 		container_of(packet, struct outbound_phy_packet_event, p);
+	struct client *e_client;
 
 	switch (status) {
 	/* expected: */
@@ -1516,9 +1517,10 @@ static void outbound_phy_packet_callback(struct fw_packet *packet,
 	}
 	e->phy_packet.data[0] = packet->timestamp;
 
+	e_client = e->client;
 	queue_event(e->client, &e->event, &e->phy_packet,
 		    sizeof(e->phy_packet) + e->phy_packet.length, NULL, 0);
-	client_put(e->client);
+	client_put(e_client);
 }
 
 static int ioctl_send_phy_packet(struct client *client, union ioctl_arg *arg)
-- 
2.34.1

[PATCH 2/3] firewire: remove check of list iterator against head past the loop body

[Takashi Sakamoto]

From: Jakob Koschel <jakobkoschel@gmail.com>

When list_for_each_entry() completes the iteration over the whole list
without breaking the loop, the iterator value will be a bogus pointer
computed based on the head element.

While it is safe to use the pointer to determine if it was computed
based on the head element, either with list_entry_is_head() or
&pos->member == head, using the iterator variable after the loop should
be avoided.

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element [1].

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Cc: <stable@vger.kernel.org>
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 drivers/firewire/core-transaction.c | 30 +++++++++++++++--------------
 drivers/firewire/sbp2.c             | 13 +++++++------
 2 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index ac487c96bb71..6c20815cc8d1 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -73,24 +73,25 @@ static int try_cancel_split_timeout(struct fw_transaction *t)
 static int close_transaction(struct fw_transaction *transaction,
 			     struct fw_card *card, int rcode)
 {
-	struct fw_transaction *t;
+	struct fw_transaction *t = NULL, *iter;
 	unsigned long flags;
 
 	spin_lock_irqsave(&card->lock, flags);
-	list_for_each_entry(t, &card->transaction_list, link) {
-		if (t == transaction) {
-			if (!try_cancel_split_timeout(t)) {
+	list_for_each_entry(iter, &card->transaction_list, link) {
+		if (iter == transaction) {
+			if (!try_cancel_split_timeout(iter)) {
 				spin_unlock_irqrestore(&card->lock, flags);
 				goto timed_out;
 			}
-			list_del_init(&t->link);
-			card->tlabel_mask &= ~(1ULL << t->tlabel);
+			list_del_init(&iter->link);
+			card->tlabel_mask &= ~(1ULL << iter->tlabel);
+			t = iter;
 			break;
 		}
 	}
 	spin_unlock_irqrestore(&card->lock, flags);
 
-	if (&t->link != &card->transaction_list) {
+	if (t) {
 		t->callback(card, rcode, NULL, 0, t->callback_data);
 		return 0;
 	}
@@ -935,7 +936,7 @@ EXPORT_SYMBOL(fw_core_handle_request);
 
 void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
 {
-	struct fw_transaction *t;
+	struct fw_transaction *t = NULL, *iter;
 	unsigned long flags;
 	u32 *data;
 	size_t data_length;
@@ -947,20 +948,21 @@ void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)
 	rcode	= HEADER_GET_RCODE(p->header[1]);
 
 	spin_lock_irqsave(&card->lock, flags);
-	list_for_each_entry(t, &card->transaction_list, link) {
-		if (t->node_id == source && t->tlabel == tlabel) {
-			if (!try_cancel_split_timeout(t)) {
+	list_for_each_entry(iter, &card->transaction_list, link) {
+		if (iter->node_id == source && iter->tlabel == tlabel) {
+			if (!try_cancel_split_timeout(iter)) {
 				spin_unlock_irqrestore(&card->lock, flags);
 				goto timed_out;
 			}
-			list_del_init(&t->link);
-			card->tlabel_mask &= ~(1ULL << t->tlabel);
+			list_del_init(&iter->link);
+			card->tlabel_mask &= ~(1ULL << iter->tlabel);
+			t = iter;
 			break;
 		}
 	}
 	spin_unlock_irqrestore(&card->lock, flags);
 
-	if (&t->link == &card->transaction_list) {
+	if (!t) {
  timed_out:
 		fw_notice(card, "unsolicited response (source %x, tlabel %x)\n",
 			  source, tlabel);
diff --git a/drivers/firewire/sbp2.c b/drivers/firewire/sbp2.c
index 85cd379fd383..60051c0cabea 100644
--- a/drivers/firewire/sbp2.c
+++ b/drivers/firewire/sbp2.c
@@ -408,7 +408,7 @@ static void sbp2_status_write(struct fw_card *card, struct fw_request *request,
 			      void *payload, size_t length, void *callback_data)
 {
 	struct sbp2_logical_unit *lu = callback_data;
-	struct sbp2_orb *orb;
+	struct sbp2_orb *orb = NULL, *iter;
 	struct sbp2_status status;
 	unsigned long flags;
 
@@ -433,17 +433,18 @@ static void sbp2_status_write(struct fw_card *card, struct fw_request *request,
 
 	/* Lookup the orb corresponding to this status write. */
 	spin_lock_irqsave(&lu->tgt->lock, flags);
-	list_for_each_entry(orb, &lu->orb_list, link) {
+	list_for_each_entry(iter, &lu->orb_list, link) {
 		if (STATUS_GET_ORB_HIGH(status) == 0 &&
-		    STATUS_GET_ORB_LOW(status) == orb->request_bus) {
-			orb->rcode = RCODE_COMPLETE;
-			list_del(&orb->link);
+		    STATUS_GET_ORB_LOW(status) == iter->request_bus) {
+			iter->rcode = RCODE_COMPLETE;
+			list_del(&iter->link);
+			orb = iter;
 			break;
 		}
 	}
 	spin_unlock_irqrestore(&lu->tgt->lock, flags);
 
-	if (&orb->link != &lu->orb_list) {
+	if (orb) {
 		orb->callback(orb, &status);
 		kref_put(&orb->kref, free_orb); /* orb callback reference */
 	} else {
-- 
2.34.1

[PATCH 3/3] firewire: core: extend card->lock in fw_core_handle_bus_reset

[Takashi Sakamoto]

From: Niels Dossche <dossche.niels@gmail.com>

card->local_node and card->bm_retries are both always accessed under
card->lock.
fw_core_handle_bus_reset has a check whose condition depends on
card->local_node and whose body writes to card->bm_retries.
Both of these accesses are not under card->lock. Move the lock acquiring
of card->lock to before this check such that these accesses do happen
when card->lock is held.
fw_destroy_nodes is called inside the check.
Since fw_destroy_nodes already acquires card->lock inside its function
body, move this out to the callsites of fw_destroy_nodes.
Also add a comment to indicate which locking is necessary when calling
fw_destroy_nodes.

Cc: <stable@vger.kernel.org>
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 drivers/firewire/core-card.c     | 3 +++
 drivers/firewire/core-topology.c | 9 +++------
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 54be88167c60..f3b3953cac83 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -668,6 +668,7 @@ EXPORT_SYMBOL_GPL(fw_card_release);
 void fw_core_remove_card(struct fw_card *card)
 {
 	struct fw_card_driver dummy_driver = dummy_driver_template;
+	unsigned long flags;
 
 	card->driver->update_phy_reg(card, 4,
 				     PHY_LINK_ACTIVE | PHY_CONTENDER, 0);
@@ -682,7 +683,9 @@ void fw_core_remove_card(struct fw_card *card)
 	dummy_driver.stop_iso		= card->driver->stop_iso;
 	card->driver = &dummy_driver;
 
+	spin_lock_irqsave(&card->lock, flags);
 	fw_destroy_nodes(card);
+	spin_unlock_irqrestore(&card->lock, flags);
 
 	/* Wait for all users, especially device workqueue jobs, to finish. */
 	fw_card_put(card);
diff --git a/drivers/firewire/core-topology.c b/drivers/firewire/core-topology.c
index b63d55f5ebd3..f40c81534381 100644
--- a/drivers/firewire/core-topology.c
+++ b/drivers/firewire/core-topology.c
@@ -375,16 +375,13 @@ static void report_found_node(struct fw_card *card,
 	card->bm_retries = 0;
 }
 
+/* Must be called with card->lock held */
 void fw_destroy_nodes(struct fw_card *card)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&card->lock, flags);
 	card->color++;
 	if (card->local_node != NULL)
 		for_each_fw_node(card, card->local_node, report_lost_node);
 	card->local_node = NULL;
-	spin_unlock_irqrestore(&card->lock, flags);
 }
 
 static void move_tree(struct fw_node *node0, struct fw_node *node1, int port)
@@ -510,6 +507,8 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
 	struct fw_node *local_node;
 	unsigned long flags;
 
+	spin_lock_irqsave(&card->lock, flags);
+
 	/*
 	 * If the selfID buffer is not the immediate successor of the
 	 * previously processed one, we cannot reliably compare the
@@ -521,8 +520,6 @@ void fw_core_handle_bus_reset(struct fw_card *card, int node_id, int generation,
 		card->bm_retries = 0;
 	}
 
-	spin_lock_irqsave(&card->lock, flags);
-
 	card->broadcast_channel_allocated = card->broadcast_channel_auto_allocated;
 	card->node_id = node_id;
 	/*
-- 
2.34.1

Re: [PATCH 0/3] firewire: fixes for kernel v4.9 or later

[Takashi Iwai]

On Sat, 09 Apr 2022 06:12:40 +0200,
Takashi Sakamoto wrote:
> 
> Hi,
> 
> This patchset respins patches posted before to fix some bugs for Linux
> FireWire subsystem. I expect them to be sent to Linus via pull request
> by maintainer of Linux sound subsystem since the path appears to be
> available after a short conversation with the maintainer. This patchset
> is expected to be applied to 'for-linus' branch for v5.18 kernel, and
> to stable kernels based on v4.9 or later.
> 
> This patchset includes below patches:
> 
> * [PATCH V2] drivers/firewire: use struct_size over open coded arithmetic
>     * https://lore.kernel.org/lkml/20220210060805.1608198-1-chi.minghao@zte.com.cn/
> * [PATCH] firewire: core: extend card->lock in fw_core_handle_bus_reset
>     * https://lore.kernel.org/lkml/20220303183038.54126-1-dossche.niels@gmail.com/
> * [PATCH] firewire: remove check of list iterator against head past the loop body
>     * https://lore.kernel.org/lkml/20220331223601.902329-1-jakobkoschel@gmail.com/
> 
> Chengfeng Ye (1):
>   firewire: fix potential uaf in outbound_phy_packet_callback()
> 
> Jakob Koschel (1):
>   firewire: remove check of list iterator against head past the loop
>     body
> 
> Niels Dossche (1):
>   firewire: core: extend card->lock in fw_core_handle_bus_reset

Now I applied all those pending patches to topic/firewire branch,
merged into for-linus branch.


thanks,

Takashi