On Thu, Apr 04, 2024 at 11:56:29AM +0200, Arnd Bergmann wrote: > On Thu, Apr 4, 2024, at 11:45, Michal Swiatkowski wrote: > > On Wed, Apr 03, 2024 at 10:59:36PM +0200, Arnd Bergmann wrote: > >> On Wed, Mar 27, 2024, at 16:23, Alexander Lobakin wrote: > >> > >> The memcpy() in the ip_tunnel_info_opts_set() causes > >> a string.h fortification warning, with at least gcc-13: > >> > >> In function 'fortify_memcpy_chk', > >> inlined from 'ip_tunnel_info_opts_set' at > >> include/net/ip_tunnels.h:619:3, > >> inlined from 'pfcp_encap_recv' at drivers/net/pfcp.c:84:2: > >> include/linux/fortify-string.h:553:25: error: call to > >> '__write_overflow_field' declared with attribute warning: detected write > >> beyond size of field (1st parameter); maybe use struct_group()? > >> [-Werror=attribute-warning] > >> 553 | __write_overflow_field(p_size_field, > >> size); > >> > >> As far as I can tell, the warning is caused by the > >> ambiguity of the union, but what I noticed is that > >> it also seems to copy a buffer to itself, as 'md' > >> is initialized to tun_dst->u.tun_info as well. > >> > >> Is this intentional? > > > > I used ip_tunnel_info_opts_set() to set options_len and flags. > > You are right that it can and probably should be changed to: > > > > __set_bit(IP_TUNNEL_PFCP_OPT_BIT, tun_dst->u.tun_info.key.tun_flags); > > tun_dst->u.tun_info.options_len = sizeof(*md); > > > > instead of copying the buffer. Thanks for pointing it. > > > > Should I sent a fix to the net or patch to the maintainer? Sorry, don't > > know how this kind of situations are being solved. > > I tend to just send fixes when I run into build problems like this, > but since you already know what's going on, I think it's best if > you send the fix as well, citing the warning I mention in the commit > log, and explaining that the warning can be avoided by the simpler > code but is otherwise a false-positive. >
Thanks, I will sent the fix ASAP. Michal > Arnd
