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authorPaul Moore <paul@paul-moore.com>2018-07-04 09:58:05 -0400
committerDavid S. Miller <davem@davemloft.net>2018-07-05 20:15:26 +0900
commita9ba23d48dbc6ffd08426bb10f05720e0b9f5c14 (patch)
tree1b9e5753be930b5709d9180738df65ad2999bbff /include
parentqed: off by one in qed_parse_mcp_trace_buf() (diff)
downloadlinux-dev-a9ba23d48dbc6ffd08426bb10f05720e0b9f5c14.tar.xz
linux-dev-a9ba23d48dbc6ffd08426bb10f05720e0b9f5c14.zip
ipv6: make ipv6_renew_options() interrupt/kernel safe
At present the ipv6_renew_options_kern() function ends up calling into access_ok() which is problematic if done from inside an interrupt as access_ok() calls WARN_ON_IN_IRQ() on some (all?) architectures (x86-64 is affected). Example warning/backtrace is shown below: WARNING: CPU: 1 PID: 3144 at lib/usercopy.c:11 _copy_from_user+0x85/0x90 ... Call Trace: <IRQ> ipv6_renew_option+0xb2/0xf0 ipv6_renew_options+0x26a/0x340 ipv6_renew_options_kern+0x2c/0x40 calipso_req_setattr+0x72/0xe0 netlbl_req_setattr+0x126/0x1b0 selinux_netlbl_inet_conn_request+0x80/0x100 selinux_inet_conn_request+0x6d/0xb0 security_inet_conn_request+0x32/0x50 tcp_conn_request+0x35f/0xe00 ? __lock_acquire+0x250/0x16c0 ? selinux_socket_sock_rcv_skb+0x1ae/0x210 ? tcp_rcv_state_process+0x289/0x106b tcp_rcv_state_process+0x289/0x106b ? tcp_v6_do_rcv+0x1a7/0x3c0 tcp_v6_do_rcv+0x1a7/0x3c0 tcp_v6_rcv+0xc82/0xcf0 ip6_input_finish+0x10d/0x690 ip6_input+0x45/0x1e0 ? ip6_rcv_finish+0x1d0/0x1d0 ipv6_rcv+0x32b/0x880 ? ip6_make_skb+0x1e0/0x1e0 __netif_receive_skb_core+0x6f2/0xdf0 ? process_backlog+0x85/0x250 ? process_backlog+0x85/0x250 ? process_backlog+0xec/0x250 process_backlog+0xec/0x250 net_rx_action+0x153/0x480 __do_softirq+0xd9/0x4f7 do_softirq_own_stack+0x2a/0x40 </IRQ> ... While not present in the backtrace, ipv6_renew_option() ends up calling access_ok() via the following chain: access_ok() _copy_from_user() copy_from_user() ipv6_renew_option() The fix presented in this patch is to perform the userspace copy earlier in the call chain such that it is only called when the option data is actually coming from userspace; that place is do_ipv6_setsockopt(). Not only does this solve the problem seen in the backtrace above, it also allows us to simplify the code quite a bit by removing ipv6_renew_options_kern() completely. We also take this opportunity to cleanup ipv6_renew_options()/ipv6_renew_option() a small amount as well. This patch is heavily based on a rough patch by Al Viro. I've taken his original patch, converted a kmemdup() call in do_ipv6_setsockopt() to a memdup_user() call, made better use of the e_inval jump target in the same function, and cleaned up the use ipv6_renew_option() by ipv6_renew_options(). CC: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/ipv6.h9
1 files changed, 1 insertions, 8 deletions
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 16475c269749..d02881e4ad1f 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -355,14 +355,7 @@ struct ipv6_txoptions *ipv6_dup_options(struct sock *sk,
struct ipv6_txoptions *ipv6_renew_options(struct sock *sk,
struct ipv6_txoptions *opt,
int newtype,
- struct ipv6_opt_hdr __user *newopt,
- int newoptlen);
-struct ipv6_txoptions *
-ipv6_renew_options_kern(struct sock *sk,
- struct ipv6_txoptions *opt,
- int newtype,
- struct ipv6_opt_hdr *newopt,
- int newoptlen);
+ struct ipv6_opt_hdr *newopt);
struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
struct ipv6_txoptions *opt);