iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

gpioib: do not free unrequested descriptors

Browse Source 
commit ab3dbcf78f60f46d6a0ad63b1f4b690b7a427140 upstream.

If the main loop in linehandle_create() encounters an error, it
unwinds completely by freeing all previously requested GPIO
descriptors.  However, if the error occurs in the beginning of
the loop before that GPIO is requested, then the exit code
attempts to free a null descriptor.  If extrachecks is enabled,
gpiod_free() triggers a WARN_ON.

Instead, keep a separate count of legitimate GPIOs so that only
those are freed.

Cc: stable@vger.kernel.org
Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Timur Tabi 2018-03-29 13:29:12 -05:00 committed by Greg Kroah-Hartman
parent ef7c4825fe
commit 0f40bb84e2
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/gpio/gpiolib.c
View File

@ -443,7 +443,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
struct gpiohandle_request handlereq;
struct linehandle_state *lh;
struct file *file;
int fd, i, ret;
int fd, i, count = 0, ret;
if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
return -EFAULT;
@ -489,6 +489,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
if (ret)
goto out_free_descs;
lh->descs[i] = desc;
count = i;
if (lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW)
set_bit(FLAG_ACTIVE_LOW, &desc->flags);
@ -555,7 +556,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
out_put_unused_fd:
put_unused_fd(fd);
out_free_descs:
for (; i >= 0; i--)
for (i = 0; i < count; i++)
gpiod_free(lh->descs[i]);
kfree(lh->label);
out_free_lh: