On Mon, May 04, 2020 at 12:08:55PM -0700, Kees Cook wrote: > Just as a precaution, make sure that proc handlers don't accidentally > grow "count" beyond the allocated kbuf size. > > Signed-off-by: Kees Cook <[email protected]> > --- > This applies to hch's sysctl cleanup tree... > --- > fs/proc/proc_sysctl.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c > index 15030784566c..535ab26473af 100644 > --- a/fs/proc/proc_sysctl.c > +++ b/fs/proc/proc_sysctl.c > @@ -546,6 +546,7 @@ static ssize_t proc_sys_call_handler(struct file *filp, > void __user *ubuf, > struct inode *inode = file_inode(filp); > struct ctl_table_header *head = grab_header(inode); > struct ctl_table *table = PROC_I(inode)->sysctl_entry; > + size_t count_max = count; > void *kbuf; > ssize_t error; > > @@ -590,6 +591,8 @@ static ssize_t proc_sys_call_handler(struct file *filp, > void __user *ubuf, > > if (!write) { > error = -EFAULT; > + if (WARN_ON(count > count_max)) > + count = count_max;
That crash a system with panic-on-warn. I don't think we want that? Luis
