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drbd: Wrong use of RCU in receive_protocol() 

It is not enough to grab net_conf->integrity_alg under rcu_read_lock()
and access it outside of it; the entire net_conf object may be gone by
then.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Andreas Gruenbacher 2011-04-28 15:24:18 +02:00 committed by Philipp Reisner
parent acb104c396
commit 86db06180a
1 changed files with 19 additions and 13 deletions
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32
drivers/block/drbd/drbd_receiver.c
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@ -2998,7 +2998,6 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
int p_proto, p_after_sb_0p, p_after_sb_1p, p_after_sb_2p;
int p_want_lose, p_two_primaries, cf;
char p_integrity_alg[SHARED_SECRET_MAX] = "";
unsigned char *my_alg;
struct net_conf *nc;
p_proto = be32_to_cpu(p->protocol);
@ -3009,6 +3008,18 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
cf = be32_to_cpu(p->conn_flags);
p_want_lose = cf & CF_WANT_LOSE;
if (tconn->agreed_pro_version >= 87) {
int err;
if (pi->size > sizeof(p_integrity_alg))
return -EIO;
err = drbd_recv_all(tconn, p_integrity_alg, pi->size);
if (err)
return err;
p_integrity_alg[SHARED_SECRET_MAX-1] = 0;
}
clear_bit(CONN_DRY_RUN, &tconn->flags);
if (cf & CF_DRY_RUN)
@ -3047,23 +3058,18 @@ static int receive_protocol(struct drbd_tconn *tconn, struct packet_info *pi)
goto disconnect_rcu_unlock;
}
my_alg = nc->integrity_alg;
rcu_read_unlock();
if (tconn->agreed_pro_version >= 87) {
int err;
err = drbd_recv_all(tconn, p_integrity_alg, pi->size);
if (err)
return err;
p_integrity_alg[SHARED_SECRET_MAX-1] = 0;
if (strcmp(p_integrity_alg, my_alg)) {
if (strcmp(p_integrity_alg, nc->integrity_alg)) {
conn_err(tconn, "incompatible setting of the data-integrity-alg\n");
goto disconnect;
}
}
rcu_read_unlock();
if (tconn->agreed_pro_version >= 87) {
conn_info(tconn, "data-integrity-alg: %s\n",
my_alg[0] ? my_alg : (unsigned char *)"<not-used>");
nc->integrity_alg[0] ? nc->integrity_alg : (unsigned char *)"<not-used>");
}
return 0;