Messages in this thread | | | From | Chen-Yu Tsai <> | Date | Fri, 17 Jan 2014 17:59:30 +0800 | Subject | Re: [PATCH RFC 1/6] net: rfkill: gpio: fix gpio name buffer size off by 1 |
| |
On Fri, Jan 17, 2014 at 5:46 PM, David Laight <David.Laight@aculab.com> wrote: > From: Chen-Yu Tsai >> snprintf should be passed the complete size of the buffer, including >> the space for '\0'. The previous code resulted in the *_reset and >> *_shutdown strings being truncated. > ... >> diff --git a/net/rfkill/rfkill-gpio.c b/net/rfkill/rfkill-gpio.c > ... >> - snprintf(rfkill->reset_name, len + 6 , "%s_reset", rfkill->name); >> - snprintf(rfkill->shutdown_name, len + 9, "%s_shutdown", rfkill->name); >> + snprintf(rfkill->reset_name, len + 7 , "%s_reset", rfkill->name); >> + snprintf(rfkill->shutdown_name, len + 10, "%s_shutdown", rfkill->name); > > I can't find the context for the above, but they look very dubious. > I'd expect: snprintf(foo, sizeof foo, ...). > If you are trying to truncate rfkill->name you need to use %.*s.
The driver allocates these buffers on the fly, a few lines above:
len = strlen(rfkill->name); rfkill->reset_name = devm_kzalloc(&pdev->dev, len + 7, GFP_KERNEL); rfkill->shutdown_name = devm_kzalloc(&pdev->dev, len + 10, GFP_KERNEL);
I am not trying to truncate rfkill->name. Rather, the buffer length passed to snprintf was wrong, so the resulting name was truncated by one character.
Thanks, ChenYu
| |