| Message ID | 151571803884.27429.7578279171286065970.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 11, 2018 at 11:59 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Thu, Jan 11, 2018 at 04:47:18PM -0800, Dan Williams wrote: >> Static analysis reports that 'offset' may be a user controlled value >> that is used as a data dependency reading from a raw_frag_vec buffer. >> In order to avoid potential leaks of kernel memory values, block >> speculative execution of the instruction stream that could issue further >> reads based on an invalid '*(rfv->c + offset)' value. >> >> Based on an original patch by Elena Reshetova. > > There is the "Co-Developed-by:" tag now, if you want to use it... Ok, thanks. > >> Cc: "David S. Miller" <davem@davemloft.net> >> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> >> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> >> Cc: netdev@vger.kernel.org >> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> >> Signed-off-by: Dan Williams <dan.j.williams@intel.com> >> --- >> net/ipv4/raw.c | 10 ++++++---- >> 1 file changed, 6 insertions(+), 4 deletions(-) > > Ugh, what is this, the 4th time I've said "I don't think this is an > issue, so why are you changing this code." to this patch. To be > followed by a "oh yeah, you are right, I'll drop it", only to see it > show back up in the next time this patch series is sent out? > > Same for the other patches in this series that I have reviewed 4, maybe > 5, times already. The "v2" is not very true here... The theme of the review feedback on v1 was 'don't put ifence in any net/ code', and that was addressed. I honestly thought the new definition of array_ptr() changed the calculus on this patch. Given the same pattern appears in the ipv6 case, and I have yet to hear that we should drop the ipv6 patch, make the code symmetric just for readability purposes. Otherwise we need a comment saying why this is safe for ipv4, but maybe not safe for ipv6, I think 'array_ptr' is effectively that comment. I.e. 'array_ptr()' is designed to be low impact for instrumenting false positives. If that new argument does not hold water I will definitely drop this patch.
On Fri, Jan 12, 2018 at 10:47:44AM -0800, Dan Williams wrote: > On Thu, Jan 11, 2018 at 11:59 PM, Greg KH <gregkh@linuxfoundation.org> wrote: > >> Cc: "David S. Miller" <davem@davemloft.net> > >> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> > >> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> > >> Cc: netdev@vger.kernel.org > >> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > >> Signed-off-by: Dan Williams <dan.j.williams@intel.com> > >> --- > >> net/ipv4/raw.c | 10 ++++++---- > >> 1 file changed, 6 insertions(+), 4 deletions(-) > > > > Ugh, what is this, the 4th time I've said "I don't think this is an > > issue, so why are you changing this code." to this patch. To be > > followed by a "oh yeah, you are right, I'll drop it", only to see it > > show back up in the next time this patch series is sent out? > > > > Same for the other patches in this series that I have reviewed 4, maybe > > 5, times already. The "v2" is not very true here... > > The theme of the review feedback on v1 was 'don't put ifence in any > net/ code', and that was addressed. > > I honestly thought the new definition of array_ptr() changed the > calculus on this patch. Given the same pattern appears in the ipv6 > case, and I have yet to hear that we should drop the ipv6 patch, make > the code symmetric just for readability purposes. Otherwise we need a > comment saying why this is safe for ipv4, but maybe not safe for ipv6, > I think 'array_ptr' is effectively that comment. I.e. 'array_ptr()' is > designed to be low impact for instrumenting false positives. If that > new argument does not hold water I will definitely drop this patch. I also argued, again in an older review of this same patch series, that the ipv6 patch should be dropped as well for this same exact reason. I didn't think you wanted to hear me rant about the same thing on both patches :) greg k-h
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 125c1eab3eaa..91091a10294f 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -57,6 +57,7 @@ #include <linux/in_route.h> #include <linux/route.h> #include <linux/skbuff.h> +#include <linux/nospec.h> #include <linux/igmp.h> #include <net/net_namespace.h> #include <net/dst.h> @@ -472,17 +473,18 @@ static int raw_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb) { struct raw_frag_vec *rfv = from; + char *rfv_buf; - if (offset < rfv->hlen) { + rfv_buf = array_ptr(rfv->hdr.c, offset, rfv->hlen); + if (rfv_buf) { int copy = min(rfv->hlen - offset, len); if (skb->ip_summed == CHECKSUM_PARTIAL) - memcpy(to, rfv->hdr.c + offset, copy); + memcpy(to, rfv_buf, copy); else skb->csum = csum_block_add( skb->csum, - csum_partial_copy_nocheck(rfv->hdr.c + offset, - to, copy, 0), + csum_partial_copy_nocheck(rfv_buf, to, copy, 0), odd); odd = 0;