* [PATCH] evdev: fix evdev_write return value on partial writes @ 2011-01-27 9:42 Peter Korsgaard 2011-01-27 9:46 ` Baruch Siach 0 siblings, 1 reply; 3+ messages in thread From: Peter Korsgaard @ 2011-01-27 9:42 UTC (permalink / raw) To: dmitry.torokhov, linux-input, baruch; +Cc: Peter Korsgaard As was recently brought up on the busybox list (http://lists.busybox.net/pipermail/busybox/2011-January/074565.html), evdev_write doesn't properly check the count argument, which will lead to a return value > count on partial writes if the remaining bytes are accessible - Causing userspace confusion. Fix it by only handling each full input_event structure, similar to how it is done in evdev_read. Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk> --- drivers/input/evdev.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index c8471a2..61fa24e 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -330,7 +330,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer, goto out; } - while (retval < count) { + while ((retval + input_event_size()) <= count) { if (input_event_from_user(buffer + retval, &event)) { retval = -EFAULT; -- 1.7.2.3 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] evdev: fix evdev_write return value on partial writes 2011-01-27 9:42 [PATCH] evdev: fix evdev_write return value on partial writes Peter Korsgaard @ 2011-01-27 9:46 ` Baruch Siach 2011-01-27 10:05 ` Peter Korsgaard 0 siblings, 1 reply; 3+ messages in thread From: Baruch Siach @ 2011-01-27 9:46 UTC (permalink / raw) To: Peter Korsgaard; +Cc: dmitry.torokhov, linux-input Hi Peter, On Thu, Jan 27, 2011 at 10:42:00AM +0100, Peter Korsgaard wrote: > As was recently brought up on the busybox list > (http://lists.busybox.net/pipermail/busybox/2011-January/074565.html), > evdev_write doesn't properly check the count argument, which will > lead to a return value > count on partial writes if the remaining bytes > are accessible - Causing userspace confusion. > > Fix it by only handling each full input_event structure, similar to how > it is done in evdev_read. > A Reporte-by here would be nice. > Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk> As I said on the Busybox list, applying this results in an endless write(1, "test\n", 5) = 0 write(1, "test\n", 5) = 0 write(1, "test\n", 5) = 0 write(1, "test\n", 5) = 0 write(1, "test\n", 5) = 0 write(1, "test\n", 5) = 0 write(1, "test\n", 5) = 0 from the command echo test > /dev/input/event0 write() should probably return -EINVAL here. baruch > --- > drivers/input/evdev.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c > index c8471a2..61fa24e 100644 > --- a/drivers/input/evdev.c > +++ b/drivers/input/evdev.c > @@ -330,7 +330,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer, > goto out; > } > > - while (retval < count) { > + while ((retval + input_event_size()) <= count) { > > if (input_event_from_user(buffer + retval, &event)) { > retval = -EFAULT; > -- > 1.7.2.3 > -- ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il - ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] evdev: fix evdev_write return value on partial writes 2011-01-27 9:46 ` Baruch Siach @ 2011-01-27 10:05 ` Peter Korsgaard 0 siblings, 0 replies; 3+ messages in thread From: Peter Korsgaard @ 2011-01-27 10:05 UTC (permalink / raw) To: Baruch Siach; +Cc: dmitry.torokhov, linux-input >>>>> "Baruch" == Baruch Siach <baruch@tkos.co.il> writes: >> Fix it by only handling each full input_event structure, similar to >> how it is done in evdev_read. Baruch> A Reporte-by here would be nice. Sorry, forgot. Dmitry, could you add it when you commit the patch. >> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk> Baruch> As I said on the Busybox list, applying this results in an endless Baruch> write(1, "test\n", 5) = 0 Baruch> write(1, "test\n", 5) = 0 Baruch> write(1, "test\n", 5) = 0 Baruch> write(1, "test\n", 5) = 0 Baruch> write(1, "test\n", 5) = 0 Baruch> write(1, "test\n", 5) = 0 Baruch> write(1, "test\n", 5) = 0 Baruch> from the command Baruch> echo test > /dev/input/event0 Baruch> write() should probably return -EINVAL here. Indeed, like we do in evdev_read. Updated patch sent. -- Bye, Peter Korsgaard ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-01-27 10:05 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-01-27 9:42 [PATCH] evdev: fix evdev_write return value on partial writes Peter Korsgaard 2011-01-27 9:46 ` Baruch Siach 2011-01-27 10:05 ` Peter Korsgaard
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