libceph: do not hard code max auth ticket len
We hard code cephx auth ticket buffer size to 256 bytes. This isn't
enough for any moderate setups and, in case tickets themselves are not
encrypted, leads to buffer overflows (ceph_x_decrypt() errors out, but
ceph_decode_copy() doesn't - it's just a memcpy() wrapper). Since the
buffer is allocated dynamically anyway, allocated it a bit later, at
the point where we know how much is going to be needed.
Fixes: http://tracker.ceph.com/issues/8979
Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@redhat.com>
diff --git a/net/ceph/auth_x.c b/net/ceph/auth_x.c
index 0eb146d..de6662b 100644
--- a/net/ceph/auth_x.c
+++ b/net/ceph/auth_x.c
@@ -13,8 +13,6 @@
#include "auth_x.h"
#include "auth_x_protocol.h"
-#define TEMP_TICKET_BUF_LEN 256
-
static void ceph_x_validate_tickets(struct ceph_auth_client *ac, int *pneed);
static int ceph_x_is_authenticated(struct ceph_auth_client *ac)
@@ -64,7 +62,7 @@
}
static int ceph_x_decrypt(struct ceph_crypto_key *secret,
- void **p, void *end, void *obuf, size_t olen)
+ void **p, void *end, void **obuf, size_t olen)
{
struct ceph_x_encrypt_header head;
size_t head_len = sizeof(head);
@@ -75,8 +73,14 @@
return -EINVAL;
dout("ceph_x_decrypt len %d\n", len);
- ret = ceph_decrypt2(secret, &head, &head_len, obuf, &olen,
- *p, len);
+ if (*obuf == NULL) {
+ *obuf = kmalloc(len, GFP_NOFS);
+ if (!*obuf)
+ return -ENOMEM;
+ olen = len;
+ }
+
+ ret = ceph_decrypt2(secret, &head, &head_len, *obuf, &olen, *p, len);
if (ret)
return ret;
if (head.struct_v != 1 || le64_to_cpu(head.magic) != CEPHX_ENC_MAGIC)
@@ -131,18 +135,19 @@
static int process_one_ticket(struct ceph_auth_client *ac,
struct ceph_crypto_key *secret,
- void **p, void *end,
- void *dbuf, void *ticket_buf)
+ void **p, void *end)
{
struct ceph_x_info *xi = ac->private;
int type;
u8 tkt_struct_v, blob_struct_v;
struct ceph_x_ticket_handler *th;
+ void *dbuf = NULL;
void *dp, *dend;
int dlen;
char is_enc;
struct timespec validity;
struct ceph_crypto_key old_key;
+ void *ticket_buf = NULL;
void *tp, *tpend;
struct ceph_timespec new_validity;
struct ceph_crypto_key new_session_key;
@@ -167,8 +172,7 @@
}
/* blob for me */
- dlen = ceph_x_decrypt(secret, p, end, dbuf,
- TEMP_TICKET_BUF_LEN);
+ dlen = ceph_x_decrypt(secret, p, end, &dbuf, 0);
if (dlen <= 0) {
ret = dlen;
goto out;
@@ -195,20 +199,25 @@
/* ticket blob for service */
ceph_decode_8_safe(p, end, is_enc, bad);
- tp = ticket_buf;
if (is_enc) {
/* encrypted */
dout(" encrypted ticket\n");
- dlen = ceph_x_decrypt(&old_key, p, end, ticket_buf,
- TEMP_TICKET_BUF_LEN);
+ dlen = ceph_x_decrypt(&old_key, p, end, &ticket_buf, 0);
if (dlen < 0) {
ret = dlen;
goto out;
}
+ tp = ticket_buf;
dlen = ceph_decode_32(&tp);
} else {
/* unencrypted */
ceph_decode_32_safe(p, end, dlen, bad);
+ ticket_buf = kmalloc(dlen, GFP_NOFS);
+ if (!ticket_buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ tp = ticket_buf;
ceph_decode_need(p, end, dlen, bad);
ceph_decode_copy(p, ticket_buf, dlen);
}
@@ -237,6 +246,8 @@
xi->have_keys |= th->service;
out:
+ kfree(ticket_buf);
+ kfree(dbuf);
return ret;
bad:
@@ -249,21 +260,10 @@
void *buf, void *end)
{
void *p = buf;
- char *dbuf;
- char *ticket_buf;
u8 reply_struct_v;
u32 num;
int ret;
- dbuf = kmalloc(TEMP_TICKET_BUF_LEN, GFP_NOFS);
- if (!dbuf)
- return -ENOMEM;
-
- ret = -ENOMEM;
- ticket_buf = kmalloc(TEMP_TICKET_BUF_LEN, GFP_NOFS);
- if (!ticket_buf)
- goto out_dbuf;
-
ceph_decode_8_safe(&p, end, reply_struct_v, bad);
if (reply_struct_v != 1)
return -EINVAL;
@@ -272,22 +272,15 @@
dout("%d tickets\n", num);
while (num--) {
- ret = process_one_ticket(ac, secret, &p, end,
- dbuf, ticket_buf);
+ ret = process_one_ticket(ac, secret, &p, end);
if (ret)
- goto out;
+ return ret;
}
- ret = 0;
-out:
- kfree(ticket_buf);
-out_dbuf:
- kfree(dbuf);
- return ret;
+ return 0;
bad:
- ret = -EINVAL;
- goto out;
+ return -EINVAL;
}
static int ceph_x_build_authorizer(struct ceph_auth_client *ac,
@@ -603,13 +596,14 @@
struct ceph_x_ticket_handler *th;
int ret = 0;
struct ceph_x_authorize_reply reply;
+ void *preply = &reply;
void *p = au->reply_buf;
void *end = p + sizeof(au->reply_buf);
th = get_ticket_handler(ac, au->service);
if (IS_ERR(th))
return PTR_ERR(th);
- ret = ceph_x_decrypt(&th->session_key, &p, end, &reply, sizeof(reply));
+ ret = ceph_x_decrypt(&th->session_key, &p, end, &preply, sizeof(reply));
if (ret < 0)
return ret;
if (ret != sizeof(reply))
