| Message ID | 20230105233420.gonna.036-kees@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] ethtool: Replace 0-length array with flexible array | expand |
On Fri. 6 Jan 2023 at 08:34, Kees Cook <keescook@chromium.org> wrote: > Zero-length arrays are deprecated[1]. Replace struct ethtool_rxnfc's > "rule_locs" 0-length array with a flexible array. Detected with GCC 13, > using -fstrict-flex-arrays=3: > > net/ethtool/common.c: In function 'ethtool_get_max_rxnfc_channel': > net/ethtool/common.c:558:55: warning: array subscript i is outside array bounds of '__u32[0]' {aka 'unsigned int[]'} [-Warray-bounds=] > 558 | .fs.location = info->rule_locs[i], > | ~~~~~~~~~~~~~~~^~~ > In file included from include/linux/ethtool.h:19, > from include/uapi/linux/ethtool_netlink.h:12, > from include/linux/ethtool_netlink.h:6, > from net/ethtool/common.c:3: > include/uapi/linux/ethtool.h:1186:41: note: while referencing > 'rule_locs' > 1186 | __u32 rule_locs[0]; > | ^~~~~~~~~ > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays > > Cc: "David S. Miller" <davem@davemloft.net> > Cc: Jakub Kicinski <kuba@kernel.org> > Cc: Andrew Lunn <andrew@lunn.ch> > Cc: kernel test robot <lkp@intel.com> > Cc: Oleksij Rempel <linux@rempel-privat.de> > Cc: Sean Anderson <sean.anderson@seco.com> > Cc: Alexandru Tachici <alexandru.tachici@analog.com> > Cc: Amit Cohen <amcohen@nvidia.com> > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > Cc: netdev@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > v2: resend, this time without missing netdev CC. :) > --- > include/uapi/linux/ethtool.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h > index 58e587ba0450..9b97b3e0ec1f 100644 > --- a/include/uapi/linux/ethtool.h > +++ b/include/uapi/linux/ethtool.h > @@ -1183,7 +1183,7 @@ struct ethtool_rxnfc { > __u32 rule_cnt; > __u32 rss_context; > }; > - __u32 rule_locs[0]; > + __DECLARE_FLEX_ARRAY(__u32, rule_locs); Can't this simply be a C99 flexible array member? __u32 rule_locs[]; As far as I understand, __DECLARE_FLEX_ARRAY() is a hack to allow the declaration of a flexible array within unions (which otherwise do not accept flexible array members). However, ethtool_rxnfc being a struct, I do not see the need for __DECLARE_FLEX_ARRAY() here. Yours sincerely, Vincent Mailhol
On Fri, Jan 06, 2023 at 09:55:30AM +0900, Vincent MAILHOL wrote: > On Fri. 6 Jan 2023 at 08:34, Kees Cook <keescook@chromium.org> wrote: > > Zero-length arrays are deprecated[1]. Replace struct ethtool_rxnfc's > > "rule_locs" 0-length array with a flexible array. Detected with GCC 13, > > using -fstrict-flex-arrays=3: > > > > net/ethtool/common.c: In function 'ethtool_get_max_rxnfc_channel': > > net/ethtool/common.c:558:55: warning: array subscript i is outside array bounds of '__u32[0]' {aka 'unsigned int[]'} [-Warray-bounds=] > > 558 | .fs.location = info->rule_locs[i], > > | ~~~~~~~~~~~~~~~^~~ > > In file included from include/linux/ethtool.h:19, > > from include/uapi/linux/ethtool_netlink.h:12, > > from include/linux/ethtool_netlink.h:6, > > from net/ethtool/common.c:3: > > include/uapi/linux/ethtool.h:1186:41: note: while referencing > > 'rule_locs' > > 1186 | __u32 rule_locs[0]; > > | ^~~~~~~~~ > > > > [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays > > > > Cc: "David S. Miller" <davem@davemloft.net> > > Cc: Jakub Kicinski <kuba@kernel.org> > > Cc: Andrew Lunn <andrew@lunn.ch> > > Cc: kernel test robot <lkp@intel.com> > > Cc: Oleksij Rempel <linux@rempel-privat.de> > > Cc: Sean Anderson <sean.anderson@seco.com> > > Cc: Alexandru Tachici <alexandru.tachici@analog.com> > > Cc: Amit Cohen <amcohen@nvidia.com> > > Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> > > Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > > Cc: netdev@vger.kernel.org > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > v2: resend, this time without missing netdev CC. :) > > --- > > include/uapi/linux/ethtool.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h > > index 58e587ba0450..9b97b3e0ec1f 100644 > > --- a/include/uapi/linux/ethtool.h > > +++ b/include/uapi/linux/ethtool.h > > @@ -1183,7 +1183,7 @@ struct ethtool_rxnfc { > > __u32 rule_cnt; > > __u32 rss_context; > > }; > > - __u32 rule_locs[0]; > > + __DECLARE_FLEX_ARRAY(__u32, rule_locs); > > Can't this simply be a C99 flexible array member? > > __u32 rule_locs[]; > > As far as I understand, __DECLARE_FLEX_ARRAY() is a hack to allow the > declaration of a flexible array within unions (which otherwise do not > accept flexible array members). However, ethtool_rxnfc being a struct, > I do not see the need for __DECLARE_FLEX_ARRAY() here. Good point -- I think my eyes scanned through the "union" above and I just jumped at using __DECLARE_FLEX_ARRAY. I'll send a v2. Thanks!
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h index 58e587ba0450..9b97b3e0ec1f 100644 --- a/include/uapi/linux/ethtool.h +++ b/include/uapi/linux/ethtool.h @@ -1183,7 +1183,7 @@ struct ethtool_rxnfc { __u32 rule_cnt; __u32 rss_context; }; - __u32 rule_locs[0]; + __DECLARE_FLEX_ARRAY(__u32, rule_locs); };
Zero-length arrays are deprecated[1]. Replace struct ethtool_rxnfc's "rule_locs" 0-length array with a flexible array. Detected with GCC 13, using -fstrict-flex-arrays=3: net/ethtool/common.c: In function 'ethtool_get_max_rxnfc_channel': net/ethtool/common.c:558:55: warning: array subscript i is outside array bounds of '__u32[0]' {aka 'unsigned int[]'} [-Warray-bounds=] 558 | .fs.location = info->rule_locs[i], | ~~~~~~~~~~~~~~~^~~ In file included from include/linux/ethtool.h:19, from include/uapi/linux/ethtool_netlink.h:12, from include/linux/ethtool_netlink.h:6, from net/ethtool/common.c:3: include/uapi/linux/ethtool.h:1186:41: note: while referencing 'rule_locs' 1186 | __u32 rule_locs[0]; | ^~~~~~~~~ [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#zero-length-and-one-element-arrays Cc: "David S. Miller" <davem@davemloft.net> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Andrew Lunn <andrew@lunn.ch> Cc: kernel test robot <lkp@intel.com> Cc: Oleksij Rempel <linux@rempel-privat.de> Cc: Sean Anderson <sean.anderson@seco.com> Cc: Alexandru Tachici <alexandru.tachici@analog.com> Cc: Amit Cohen <amcohen@nvidia.com> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: Vincent Mailhol <mailhol.vincent@wanadoo.fr> Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- v2: resend, this time without missing netdev CC. :) --- include/uapi/linux/ethtool.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)