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| author | David Windsor <dave@nullcore.net> | 2017-06-10 22:50:42 -0400 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2018-01-15 12:07:58 -0800 |
| commit | 30c2c9f158f6c9cef41e916d1c7c11097df4befb (patch) | |
| tree | d03ac031c75ba6d85871fd1a5cd0ec8ddd2ebf16 | |
| parent | 0afe76e88c57d91ef5697720aed380a339e3df70 (diff) | |
| download | linux-stable-30c2c9f158f6c9cef41e916d1c7c11097df4befb.tar.gz linux-stable-30c2c9f158f6c9cef41e916d1c7c11097df4befb.tar.bz2 linux-stable-30c2c9f158f6c9cef41e916d1c7c11097df4befb.zip | |
net: Define usercopy region in struct proto slab cache
In support of usercopy hardening, this patch defines a region in the
struct proto slab cache in which userspace copy operations are allowed.
Some protocols need to copy objects to/from userspace, and they can
declare the region via their proto structure with the new usersize and
useroffset fields. Initially, if no region is specified (usersize ==
0), the entire field is marked as whitelisted. This allows protocols
to be whitelisted in subsequent patches. Once all protocols have been
annotated, the full-whitelist default can be removed.
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@nullcore.net>
[kees: adjust commit log, split off per-proto patches]
[kees: add logic for by-default full-whitelist]
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | include/net/sock.h | 2 | ||||
| -rw-r--r-- | net/core/sock.c | 6 |
2 files changed, 7 insertions, 1 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 79e1a2c7912c..b77a710ee831 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1112,6 +1112,8 @@ struct proto { struct kmem_cache *slab; unsigned int obj_size; slab_flags_t slab_flags; + size_t useroffset; /* Usercopy region offset */ + size_t usersize; /* Usercopy region size */ struct percpu_counter *orphan_count; diff --git a/net/core/sock.c b/net/core/sock.c index c0b5b2f17412..261e6dbf0259 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3151,8 +3151,12 @@ static int req_prot_init(const struct proto *prot) int proto_register(struct proto *prot, int alloc_slab) { if (alloc_slab) { - prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0, + prot->slab = kmem_cache_create_usercopy(prot->name, + prot->obj_size, 0, SLAB_HWCACHE_ALIGN | prot->slab_flags, + prot->usersize ? prot->useroffset : 0, + prot->usersize ? prot->usersize + : prot->obj_size, NULL); if (prot->slab == NULL) { |