Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 1/1] HID: hidraw, fix window in hidraw_release | Date | Tue, 19 Oct 2010 11:24:45 +0200 |
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There is a window between hidraw_table check and its dereference. In that window, the device may be unplugged and removed form the system and we will then dereference NULL.
Lock that place properly so that either we get NULL and jump out or we can work with real pointer.
Signed-off-by: Jiri Slaby <jslaby@suse.cz> --- drivers/hid/hidraw.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c index 925992f..6d81be3 100644 --- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -218,9 +218,13 @@ static int hidraw_release(struct inode * inode, struct file * file) unsigned int minor = iminor(inode); struct hidraw *dev; struct hidraw_list *list = file->private_data; + int ret; - if (!hidraw_table[minor]) - return -ENODEV; + mutex_lock(&minors_lock); + if (!hidraw_table[minor]) { + ret = -ENODEV; + goto unlock; + } list_del(&list->node); dev = hidraw_table[minor]; @@ -233,10 +237,12 @@ static int hidraw_release(struct inode * inode, struct file * file) kfree(list->hidraw); } } - + ret = 0; +unlock: + mutex_unlock(&minors_lock); kfree(list); - return 0; + return ret; } static long hidraw_ioctl(struct file *file, unsigned int cmd, -- 1.7.3.1
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