On Mon, Oct 29, 2018 at 7:58 AM, Christian Brauner <christian@xxxxxxxxxx> wrote: > On Wed, Oct 17, 2018 at 12:33:20AM +0200, Christian Brauner wrote: >> Hey, >> >> Here is v3 of this patchset. Changelogs are in the individual commits. >> >> Currently, when writing >> >> echo 18446744073709551616 > /proc/sys/fs/file-max >> >> /proc/sys/fs/file-max will overflow and be set to 0. That quickly >> crashes the system. >> >> The first version of this patch intended to detect the overflow and cap >> at ULONG_MAX. However, we should not do this and rather return EINVAL on >> overflow. The reasons are: >> - this aligns with other sysctl handlers that simply reject overflows >> (cf. [1], [2], and a bunch of others) >> - we already do a partial fail on overflow right now >> Namely, when the TMPBUFLEN is exceeded. So we already reject values >> such as 184467440737095516160 (21 chars) but accept values such as >> 18446744073709551616 (20 chars) but both are overflows. So we should >> just always reject 64bit overflows and not special-case this based on >> the number of chars. >> >> (This patchset is in reference to https://lkml.org/lkml/2018/10/11/585.) > > Just so that we don't forget, can we make sure that this gets picked > into linux-next? :) I was hoping akpm would take this? Andrew, does the v3 look okay to you? -Kees -- Kees Cook
