From 8c2bc895a9347846b33c47124a75db624aa83677 Mon Sep 17 00:00:00 2001 From: David Windsor Date: Thu, 24 Aug 2017 16:49:14 -0700 Subject: [PATCH] ip: Define usercopy region in IP proto slab cache The ICMP filters for IPv4 and IPv6 raw sockets need to be copied to/from userspace. In support of usercopy hardening, this patch defines a region in the struct proto slab cache in which userspace copy operations are allowed. example usage trace: net/ipv4/raw.c: raw_seticmpfilter(...): ... copy_from_user(&raw_sk(sk)->filter, ..., optlen) raw_geticmpfilter(...): ... copy_to_user(..., &raw_sk(sk)->filter, len) net/ipv6/raw.c: rawv6_seticmpfilter(...): ... copy_from_user(&raw6_sk(sk)->filter, ..., optlen) rawv6_geticmpfilter(...): ... copy_to_user(..., &raw6_sk(sk)->filter, len) This region is known as the slab cache's usercopy region. Slab caches can now check that each dynamically sized copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY whitelisting code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Signed-off-by: David Windsor [kees: split from network patch, provide usage trace] Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: Hideaki YOSHIFUJI Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- net/ipv4/raw.c | 2 ++ net/ipv6/raw.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 33b70bfd1122..1b6fa4195ac9 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -970,6 +970,8 @@ struct proto raw_prot = { .hash = raw_hash_sk, .unhash = raw_unhash_sk, .obj_size = sizeof(struct raw_sock), + .useroffset = offsetof(struct raw_sock, filter), + .usersize = sizeof_field(struct raw_sock, filter), .h.raw_hash = &raw_v4_hashinfo, #ifdef CONFIG_COMPAT .compat_setsockopt = compat_raw_setsockopt, diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 761a473a07c5..08a85fabdfd1 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -1272,6 +1272,8 @@ struct proto rawv6_prot = { .hash = raw_hash_sk, .unhash = raw_unhash_sk, .obj_size = sizeof(struct raw6_sock), + .useroffset = offsetof(struct raw6_sock, filter), + .usersize = sizeof_field(struct raw6_sock, filter), .h.raw_hash = &raw_v6_hashinfo, #ifdef CONFIG_COMPAT .compat_setsockopt = compat_rawv6_setsockopt,