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From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To: rspringer@google.com, toddpoynor@google.com,
	benchan@chromium.org, rcy@google.com, gregkh@linuxfoundation.org
Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
	Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device
Date: Tue, 27 Apr 2021 07:11:29 -0700	[thread overview]
Message-ID: <20210427141129.6207-1-lyl2019@mail.ustc.edu.cn> (raw)

In gasket_enable_device, it calls gasket_interrupt_init().
Inside gasket_interrupt_init, interrupt_data is allocated via
kzalloc() and then is assigned to gasket_dev->interrupt_data.
If the later two kzalloc() failed, interrupt_data will be freed
and gasket_dev->interrupt_data will point to a freed memory.

After gasket_enable_device received the error, the freed
gasket_dev->interrupt_data is freed again in
gasket_interrupt_cleanup(gasket_dev).

My patch moves the "gasket_dev->interrupt_data = interrupt_data"
assignment behind the later kzalloc() all successd, to avoid
gasket_dev->interrupt_data pointing to a freed memory

Fixes: 80666096eb78f ("staging: gasket: core: remove static function forward declarations")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/staging/gasket/gasket_interrupt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/gasket/gasket_interrupt.c b/drivers/staging/gasket/gasket_interrupt.c
index 864342acfd86..d4993d7abb87 100644
--- a/drivers/staging/gasket/gasket_interrupt.c
+++ b/drivers/staging/gasket/gasket_interrupt.c
@@ -322,7 +322,6 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
 	interrupt_data = kzalloc(sizeof(*interrupt_data), GFP_KERNEL);
 	if (!interrupt_data)
 		return -ENOMEM;
-	gasket_dev->interrupt_data = interrupt_data;
 	interrupt_data->name = driver_desc->name;
 	interrupt_data->type = driver_desc->interrupt_type;
 	interrupt_data->pci_dev = gasket_dev->pci_dev;
@@ -349,6 +348,8 @@ int gasket_interrupt_init(struct gasket_dev *gasket_dev)
 		return -ENOMEM;
 	}
 
+	gasket_dev->interrupt_data = interrupt_data;
+
 	switch (interrupt_data->type) {
 	case PCI_MSIX:
 		ret = gasket_interrupt_msix_init(interrupt_data);
-- 
2.25.1



             reply	other threads:[~2021-04-27 14:12 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-27 14:11 Lv Yunlong [this message]
2021-04-27 14:26 ` [PATCH] Staging:gasket:core: Fix a double free in gasket_enable_device Fabio Aiuto
2021-04-27 15:02   ` lyl2019

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