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authorDavid Windsor <dave@nullcore.net>2017-08-24 16:57:57 -0700
committerKees Cook <keescook@chromium.org>2018-01-15 12:08:00 -0800
commitab9ee8e38b292f9a6698a4fedbb6ff8d08ce2012 (patch)
tree48ed5e335b8495d83cd2c6fbd6bb64889f567649 /net/sctp
parent93070d339d7bc6f6b07b64faf5134fd144e8ec48 (diff)
downloadlinux-ab9ee8e38b292f9a6698a4fedbb6ff8d08ce2012.tar.bz2
sctp: Define usercopy region in SCTP proto slab cache
The SCTP socket event notification subscription information 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. Additionally moves the usercopy fields to be adjacent for the region to cover both. example usage trace: net/sctp/socket.c: sctp_getsockopt_events(...): ... copy_to_user(..., &sctp_sk(sk)->subscribe, len) sctp_setsockopt_events(...): ... copy_from_user(&sctp_sk(sk)->subscribe, ..., optlen) sctp_getsockopt_initmsg(...): ... copy_to_user(..., &sctp_sk(sk)->initmsg, 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@nullcore.net> [kees: split from network patch, move struct members adjacent] [kees: add SCTPv6 struct whitelist, provide usage trace] Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-sctp@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'net/sctp')
-rw-r--r--net/sctp/socket.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 014847e25648..efbc8f52c531 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -8470,6 +8470,10 @@ struct proto sctp_prot = {
.unhash = sctp_unhash,
.get_port = sctp_get_port,
.obj_size = sizeof(struct sctp_sock),
+ .useroffset = offsetof(struct sctp_sock, subscribe),
+ .usersize = offsetof(struct sctp_sock, initmsg) -
+ offsetof(struct sctp_sock, subscribe) +
+ sizeof_field(struct sctp_sock, initmsg),
.sysctl_mem = sysctl_sctp_mem,
.sysctl_rmem = sysctl_sctp_rmem,
.sysctl_wmem = sysctl_sctp_wmem,
@@ -8509,6 +8513,10 @@ struct proto sctpv6_prot = {
.unhash = sctp_unhash,
.get_port = sctp_get_port,
.obj_size = sizeof(struct sctp6_sock),
+ .useroffset = offsetof(struct sctp6_sock, sctp.subscribe),
+ .usersize = offsetof(struct sctp6_sock, sctp.initmsg) -
+ offsetof(struct sctp6_sock, sctp.subscribe) +
+ sizeof_field(struct sctp6_sock, sctp.initmsg),
.sysctl_mem = sysctl_sctp_mem,
.sysctl_rmem = sysctl_sctp_rmem,
.sysctl_wmem = sysctl_sctp_wmem,