On Mon, Jan 11, 2021 at 03:21:31PM +0100, Michal Hocko wrote: > On Mon 11-01-21 11:48:19, Xiaoming Ni wrote: > [...] > > patch3: > > +++ b/fs/proc/proc_sysctl.c > > @@ -1770,6 +1770,9 @@ static int process_sysctl_arg(char *param, char *val, > > return 0; > > } > > > > + if (!val) > > + return -EINVAL; > > + > > /* > > * To set sysctl options, we use a temporary mount of proc, look up the > > * respective sys/ file and write to it. To avoid mounting it when no > > > > sysctl log for patch3: > > Setting sysctl args: `' invalid for parameter `hung_task_panic' > [...] > > When process_sysctl_arg() is called, the param parameter may not be the > > sysctl parameter. > > > > Patch3 or patch4, which is better? > > Patch3 Oh, I see the issue here -- I thought we were only calling process_sysctl_arg() with valid sysctl fields. It looks like we're not, which means it should silently ignore everything that isn't a sysctl field, and only return -EINVAL when it IS a sysctl but it lacks a value. -- Kees Cook
