From: David Windsor <dave@xxxxxxxxxxxx>
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 <dave@xxxxxxxxxxxx>
[kees: split from network patch, provide usage trace]
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
Cc: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
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,
--
2.7.4
