Once device_register() failed, we should call put_device() to
decrement reference count for cleanup. Or it could cause memory leak.
As comment of device_register() says, 'NOTE: _Never_ directly free
@dev after calling this function, even if it returned an error! Always
use put_device() to give up the reference initialized in this function
instead.'
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
Changes in v5:
- modified the bug description as suggestions;
Changes in v4:
- deleted the redundant initialization;
Changes in v3:
- modified the patch as suggestions;
Changes in v2:
- modified the patch as suggestions.
---
arch/arm/common/locomo.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/arch/arm/common/locomo.c b/arch/arm/common/locomo.c
index cb6ef449b987..45106066a17f 100644
--- a/arch/arm/common/locomo.c
+++ b/arch/arm/common/locomo.c
@@ -223,10 +223,8 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info)
int ret;
dev = kzalloc(sizeof(struct locomo_dev), GFP_KERNEL);
- if (!dev) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!dev)
+ return -ENOMEM;
/*
* If the parent device has a DMA mask associated with it,
@@ -254,10 +252,9 @@ locomo_init_one_child(struct locomo *lchip, struct locomo_dev_info *info)
NO_IRQ : lchip->irq_base + info->irq[0];
ret = device_register(&dev->dev);
- if (ret) {
- out:
- kfree(dev);
- }
+ if (ret)
+ put_device(&dev->dev);
+
return ret;
}
--
2.25.1
Once of_device_register() failed, we should call put_device() to
decrement reference count for cleanup. Or it could cause memory leak.
So fix this by calling put_device(), then the name can be freed in
kobject_cleanup().
As comment of device_add() says, 'if device_add() succeeds, you should
call device_del() when you want to get rid of it. If device_add() has
not succeeded, use only put_device() to drop the reference count'.
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: cf44bbc26cf1 ("[SPARC]: Beginnings of generic of_device framework.")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
arch/sparc/kernel/of_device_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/sparc/kernel/of_device_64.c b/arch/sparc/kernel/of_device_64.c
index f98c2901f335..4272746d7166 100644
--- a/arch/sparc/kernel/of_device_64.c
+++ b/arch/sparc/kernel/of_device_64.c
@@ -677,7 +677,7 @@ static struct platform_device * __init scan_one_device(struct device_node *dp,
if (of_device_register(op)) {
printk("%pOF: Could not register of device.\n", dp);
- kfree(op);
+ put_device(&op->dev);
op = NULL;
}
--
2.25.1
sctp_sendmsg() re-uses associations and transports when possible by
doing a lookup based on the socket endpoint and the message destination
address, and then sctp_sendmsg_to_asoc() sets the selected transport in
all the message chunks to be sent.
There's a possible race condition if another thread triggers the removal
of that selected transport, for instance, by explicitly unbinding an
address with setsockopt(SCTP_SOCKOPT_BINDX_REM), after the chunks have
been set up and before the message is sent. This causes the access to
the transport data in sctp_outq_select_transport(), when the association
outqueue is flushed, to do a use-after-free read.
This patch addresses this scenario by checking if the transport still
exists right after the chunks to be sent are set up to use it and before
proceeding to sending them. If the transport was freed since it was
found, the send is aborted. The reason to add the check here is that
once the transport is assigned to the chunks, deleting that transport
is safe, since it will also set chunk->transport to NULL in the affected
chunks. This scenario is correctly handled already, see Fixes below.
The bug was found by a private syzbot instance (see the error report [1]
and the C reproducer that triggers it [2]).
Link: https://people.igalia.com/rcn/kernel_logs/20250402__KASAN_slab-use-after-fr… [1]
Link: https://people.igalia.com/rcn/kernel_logs/20250402__KASAN_slab-use-after-fr… [2]
Cc: stable(a)vger.kernel.org
Fixes: df132eff4638 ("sctp: clear the transport of some out_chunk_list chunks in sctp_assoc_rm_peer")
Signed-off-by: Ricardo Cañuelo Navarro <rcn(a)igalia.com>
---
net/sctp/socket.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 36ee34f483d703ffcfe5ca9e6cc554fba24c75ef..9c5ff44fa73cae6a6a04790800cc33dfa08a8da9 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1787,17 +1787,24 @@ static int sctp_sendmsg_check_sflags(struct sctp_association *asoc,
return 1;
}
+static union sctp_addr *sctp_sendmsg_get_daddr(struct sock *sk,
+ const struct msghdr *msg,
+ struct sctp_cmsgs *cmsgs);
+
static int sctp_sendmsg_to_asoc(struct sctp_association *asoc,
struct msghdr *msg, size_t msg_len,
struct sctp_transport *transport,
struct sctp_sndrcvinfo *sinfo)
{
+ struct sctp_transport *aux_transport = NULL;
struct sock *sk = asoc->base.sk;
+ struct sctp_endpoint *ep = sctp_sk(sk)->ep;
struct sctp_sock *sp = sctp_sk(sk);
struct net *net = sock_net(sk);
struct sctp_datamsg *datamsg;
bool wait_connect = false;
struct sctp_chunk *chunk;
+ union sctp_addr *daddr;
long timeo;
int err;
@@ -1869,6 +1876,15 @@ static int sctp_sendmsg_to_asoc(struct sctp_association *asoc,
sctp_set_owner_w(chunk);
chunk->transport = transport;
}
+ /* Fail if transport was deleted after lookup in sctp_sendmsg() */
+ daddr = sctp_sendmsg_get_daddr(sk, msg, NULL);
+ if (daddr) {
+ sctp_endpoint_lookup_assoc(ep, daddr, &aux_transport);
+ if (!aux_transport || aux_transport != transport) {
+ sctp_datamsg_free(datamsg);
+ goto err;
+ }
+ }
err = sctp_primitive_SEND(net, asoc, datamsg);
if (err) {
---
base-commit: 38fec10eb60d687e30c8c6b5420d86e8149f7557
change-id: 20250402-kasan_slab-use-after-free_read_in_sctp_outq_select_transport-46c9c30bcb7d
Once cdev_device_add() failed, we should use put_device() to decrement
reference count for cleanup. Or it could cause memory leak. Although
operations in err_free_ida are similar to the operations in callback
function fsi_slave_release(), put_device() is a correct handling
operation as comments require when cdev_device_add() fails.
As comment of device_add() says, 'if device_add() succeeds, you should
call device_del() when you want to get rid of it. If device_add() has
not succeeded, use only put_device() to drop the reference count'.
Found by code review.
Cc: stable(a)vger.kernel.org
Fixes: 371975b0b075 ("fsi/core: Fix error paths on CFAM init")
Signed-off-by: Ma Ke <make24(a)iscas.ac.cn>
---
drivers/fsi/fsi-core.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index 50e8736039fe..c494fc0bd747 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -1084,7 +1084,8 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
rc = cdev_device_add(&slave->cdev, &slave->dev);
if (rc) {
dev_err(&slave->dev, "Error %d creating slave device\n", rc);
- goto err_free_ida;
+ put_device(&slave->dev);
+ return rc;
}
/* Now that we have the cdev registered with the core, any fatal
@@ -1110,8 +1111,6 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
return 0;
-err_free_ida:
- fsi_free_minor(slave->dev.devt);
err_free:
of_node_put(slave->dev.of_node);
kfree(slave);
--
2.25.1