[PATCH 57/64] netfilter: conntrack: Use struct_group() to zero struct nf_conn
From: Kees Cook <hidden>
Date: 2021-07-27 21:16:54
Also in:
dri-devel, linux-hardening, linux-kbuild, linux-staging, linux-wireless, lkml, netdev
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields. Replace the empty __nfct_init_offset member with a struct_group() to mark the region of struct nf_conn that should be initialized to zero, allowing memset() to correctly reason about the size of the write. Signed-off-by: Kees Cook <redacted> --- include/net/netfilter/nf_conntrack.h | 20 ++++++++++---------- net/netfilter/nf_conntrack_core.c | 4 +--- 2 files changed, 11 insertions(+), 13 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index cc663c68ddc4..51004fce2937 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h@@ -101,24 +101,24 @@ struct nf_conn { struct hlist_node nat_bysource; #endif /* all members below initialized via memset */ - struct { } __nfct_init_offset; - - /* If we were expected by an expectation, this will be it */ - struct nf_conn *master; + struct_group(init, + /* If we were expected by an expectation, this will be it */ + struct nf_conn *master; #if defined(CONFIG_NF_CONNTRACK_MARK) - u_int32_t mark; + u_int32_t mark; #endif #ifdef CONFIG_NF_CONNTRACK_SECMARK - u_int32_t secmark; + u_int32_t secmark; #endif - /* Extensions */ - struct nf_ct_ext *ext; + /* Extensions */ + struct nf_ct_ext *ext; - /* Storage reserved for other modules, must be the last member */ - union nf_conntrack_proto proto; + /* Storage reserved for other modules, must be the last member */ + union nf_conntrack_proto proto; + ); }; static inline struct nf_conn *
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 5c03e5106751..b05eb64ec788 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c@@ -1527,9 +1527,7 @@ __nf_conntrack_alloc(struct net *net, ct->status = 0; ct->timeout = 0; write_pnet(&ct->ct_net, net); - memset(&ct->__nfct_init_offset, 0, - offsetof(struct nf_conn, proto) - - offsetof(struct nf_conn, __nfct_init_offset)); + memset(&ct->init, 0, sizeof(ct->init)); nf_ct_zone_add(ct, zone);
--
2.30.2