Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH v2 19/30] ip: Define usercopy region in IP proto slab cache | Date | Mon, 28 Aug 2017 14:35:00 -0700 |
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From: David Windsor <dave@nullcore.net>
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 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@nullcore.net> [kees: split from network patch, provide usage trace] Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- 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 b0bb5d0a30bd..6c7f8d2eb3af 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -964,6 +964,8 @@ 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 60be012fe708..27dd9a5f71c6 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -1265,6 +1265,8 @@ 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
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