From: Kees Cook Date: Tue, 10 May 2022 22:46:26 +0000 (-0700) Subject: af_unix: Silence randstruct GCC plugin warning X-Git-Tag: v6.1-rc5~1242^2~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b146cbf2e32f01f56244d670aef2f43d44fcf120;p=platform%2Fkernel%2Flinux-starfive.git af_unix: Silence randstruct GCC plugin warning While preparing for Clang randstruct support (which duplicated many of the warnings the randstruct GCC plugin warned about), one strange one remained only for the randstruct GCC plugin. Eliminating this rids the plugin of the last exception. It seems the plugin is happy to dereference individual members of a cross-struct cast, but it is upset about casting to a whole object pointer. This only manifests in one place in the kernel, so just replace the variable with individual member accesses. There is no change in executable instruction output. Drop the last exception from the randstruct GCC plugin. Cc: "David S. Miller" Cc: Christoph Hellwig Cc: Paolo Abeni Cc: Alexei Starovoitov Cc: Cong Wang Cc: Al Viro Cc: netdev@vger.kernel.org Cc: linux-hardening@vger.kernel.org Acked-by: Kuniyuki Iwashima Link: https://lore.kernel.org/lkml/20220511022217.58586-1-kuniyu@amazon.co.jp Acked-by: Jakub Kicinski Link: https://lore.kernel.org/lkml/20220511151542.4cb3ff17@kernel.org Signed-off-by: Kees Cook --- diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index e71a312..36367e7 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1808,11 +1808,9 @@ static int maybe_init_creds(struct scm_cookie *scm, static bool unix_skb_scm_eq(struct sk_buff *skb, struct scm_cookie *scm) { - const struct unix_skb_parms *u = &UNIXCB(skb); - - return u->pid == scm->pid && - uid_eq(u->uid, scm->creds.uid) && - gid_eq(u->gid, scm->creds.gid) && + return UNIXCB(skb).pid == scm->pid && + uid_eq(UNIXCB(skb).uid, scm->creds.uid) && + gid_eq(UNIXCB(skb).gid, scm->creds.gid) && unix_secdata_eq(scm, skb); } diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c b/scripts/gcc-plugins/randomize_layout_plugin.c index c9d345a..2ca768d8 100644 --- a/scripts/gcc-plugins/randomize_layout_plugin.c +++ b/scripts/gcc-plugins/randomize_layout_plugin.c @@ -46,8 +46,6 @@ struct whitelist_entry { }; static const struct whitelist_entry whitelist[] = { - /* unix_skb_parms via UNIXCB() buffer */ - { "net/unix/af_unix.c", "unix_skb_parms", "char" }, { } };