Commit 24599e61 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller

net: sctp: check proc_dointvec result in proc_sctp_do_auth

When writing to the sysctl field net.sctp.auth_enable, it can well
be that the user buffer we handed over to proc_dointvec() via
proc_sctp_do_auth() handler contains something other than integers.

In that case, we would set an uninitialized 4-byte value from the
stack to net->sctp.auth_enable that can be leaked back when reading
the sysctl variable, and it can unintentionally turn auth_enable
on/off based on the stack content since auth_enable is interpreted
as a boolean.

Fix it up by making sure proc_dointvec() returned sucessfully.

Fixes: b14878cc ("net: sctp: cache auth_enable per endpoint")
Reported-by: default avatarFlorian Westphal <fwestpha@redhat.com>
Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Acked-by: default avatarVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 40c1deaf
......@@ -447,8 +447,7 @@ static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
tbl.data = &net->sctp.auth_enable;
ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
if (write) {
if (write && ret == 0) {
struct sock *sk = net->sctp.ctl_sock;
net->sctp.auth_enable = new_value;
......
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