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From 803f226e749138713b5c767b1a108544ce5e0baf Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Tue, 18 Aug 2015 11:32:15 +0200
Subject: [PATCH gnumach 5/5] ipc: fix locking issues
* ipc/ipc_port.h (struct ipc_port): Document locking exception.
* ipc/ipc_port.c (ipc_port_destroy): Avoid accessing `port's fields
without the lock.
(ipc_port_alloc_special): Lock `port'.
* ipc/mach_msg.c (mach_msg_trap): Avoid using
`ipc_port_flag_protected_payload' on unlocked port.
* ipc/ipc_kmsg.c (ipc_kmsg_copyout_header): Likewise.
---
ipc/ipc_kmsg.c | 16 ++++++++++++----
ipc/ipc_port.c | 11 ++++++-----
ipc/ipc_port.h | 2 ++
ipc/mach_msg.c | 16 +++++++++++++---
4 files changed, 33 insertions(+), 12 deletions(-)
diff --git a/ipc/ipc_kmsg.c b/ipc/ipc_kmsg.c
index 5076809..6c4b59a 100644
--- a/ipc/ipc_kmsg.c
+++ b/ipc/ipc_kmsg.c
@@ -1713,6 +1713,7 @@ ipc_kmsg_copyout_header(
mach_port_t dest_name;
ipc_port_t nsrequest;
unsigned long payload;
+ int have_payload;
/* receiving an asynchronous message */
@@ -1732,6 +1733,7 @@ ipc_kmsg_copyout_header(
else
dest_name = MACH_PORT_NULL;
payload = dest->ip_protected_payload;
+ have_payload = ipc_port_flag_protected_payload(dest);
if ((--dest->ip_srights == 0) &&
((nsrequest = dest->ip_nsrequest) != IP_NULL)) {
@@ -1745,7 +1747,7 @@ ipc_kmsg_copyout_header(
} else
ip_unlock(dest);
- if (! ipc_port_flag_protected_payload(dest)) {
+ if (! have_payload) {
msg->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
MACH_MSGH_BITS(0, MACH_MSG_TYPE_PORT_SEND));
msg->msgh_local_port = dest_name;
@@ -1766,6 +1768,7 @@ ipc_kmsg_copyout_header(
mach_port_t dest_name, reply_name;
ipc_port_t nsrequest;
unsigned long payload;
+ int have_payload;
/* receiving a request message */
@@ -1837,6 +1840,7 @@ ipc_kmsg_copyout_header(
else
dest_name = MACH_PORT_NULL;
payload = dest->ip_protected_payload;
+ have_payload = ipc_port_flag_protected_payload(dest);
if ((--dest->ip_srights == 0) &&
((nsrequest = dest->ip_nsrequest) != IP_NULL)) {
@@ -1850,7 +1854,7 @@ ipc_kmsg_copyout_header(
} else
ip_unlock(dest);
- if (! ipc_port_flag_protected_payload(dest)) {
+ if (! have_payload) {
msg->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE,
MACH_MSG_TYPE_PORT_SEND));
@@ -1868,6 +1872,7 @@ ipc_kmsg_copyout_header(
case MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE, 0): {
mach_port_t dest_name;
unsigned long payload;
+ int have_payload;
/* receiving a reply message */
@@ -1882,6 +1887,7 @@ ipc_kmsg_copyout_header(
assert(dest->ip_sorights > 0);
payload = dest->ip_protected_payload;
+ have_payload = ipc_port_flag_protected_payload(dest);
if (dest->ip_receiver == space) {
ip_release(dest);
@@ -1895,7 +1901,7 @@ ipc_kmsg_copyout_header(
dest_name = MACH_PORT_NULL;
}
- if (! ipc_port_flag_protected_payload(dest)) {
+ if (! have_payload) {
msg->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
MACH_MSGH_BITS(0,
MACH_MSG_TYPE_PORT_SEND_ONCE));
@@ -1922,6 +1928,7 @@ ipc_kmsg_copyout_header(
ipc_port_t reply = (ipc_port_t) msg->msgh_local_port;
mach_port_t dest_name, reply_name;
unsigned long payload;
+ int have_payload;
if (IP_VALID(reply)) {
ipc_port_t notify_port;
@@ -2161,6 +2168,7 @@ ipc_kmsg_copyout_header(
copyout_dest:
payload = dest->ip_protected_payload;
+ have_payload = ipc_port_flag_protected_payload(dest);
if (ip_active(dest)) {
ipc_object_copyout_dest(space, (ipc_object_t) dest,
@@ -2189,7 +2197,7 @@ ipc_kmsg_copyout_header(
if (IP_VALID(reply))
ipc_port_release(reply);
- if (! ipc_port_flag_protected_payload(dest)) {
+ if (! have_payload) {
msg->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
MACH_MSGH_BITS(reply_type, dest_type));
msg->msgh_local_port = dest_name;
diff --git a/ipc/ipc_port.c b/ipc/ipc_port.c
index 86a4ee2..4e4ad59 100644
--- a/ipc/ipc_port.c
+++ b/ipc/ipc_port.c
@@ -694,11 +694,13 @@ ipc_port_destroy(
port->ip_object.io_bits &= ~IO_BITS_ACTIVE;
port->ip_timestamp = ipc_port_timestamp();
+
+ nsrequest = port->ip_nsrequest;
+ dnrequests = port->ip_dnrequests;
+
ip_unlock(port);
/* throw away no-senders request */
-
- nsrequest = port->ip_nsrequest;
if (nsrequest != IP_NULL)
ipc_notify_send_once(nsrequest); /* consumes ref */
@@ -725,8 +727,6 @@ ipc_port_destroy(
imq_unlock(mqueue);
/* generate dead-name notifications */
-
- dnrequests = port->ip_dnrequests;
if (dnrequests != IPR_NULL) {
ipc_table_size_t its = dnrequests->ipr_size;
ipc_table_elems_t size = its->its_size;
@@ -1183,6 +1183,7 @@ ipc_port_alloc_special(ipc_space_t space)
return IP_NULL;
ip_lock_init(port);
+ ip_lock(port);
port->ip_references = 1;
port->ip_object.io_bits = io_makebits(TRUE, IOT_PORT, 0);
@@ -1198,7 +1199,7 @@ ipc_port_alloc_special(ipc_space_t space)
*/
ipc_port_init(port, space, (mach_port_t)port);
-
+ ip_unlock(port);
return port;
}
diff --git a/ipc/ipc_port.h b/ipc/ipc_port.h
index ade6967..de43b42 100644
--- a/ipc/ipc_port.h
+++ b/ipc/ipc_port.h
@@ -82,6 +82,8 @@ struct ipc_port {
ipc_port_timestamp_t timestamp;
} data;
+ /* Note: For pagers (IKOT_PAGER), this field is protected by
+ vm_object_cache_lock. */
ipc_kobject_t ip_kobject;
mach_port_mscount_t ip_mscount;
diff --git a/ipc/mach_msg.c b/ipc/mach_msg.c
index fe0c43e..371d725 100644
--- a/ipc/mach_msg.c
+++ b/ipc/mach_msg.c
@@ -954,6 +954,7 @@ mach_msg_trap(
(ipc_port_t) kmsg->ikm_header.msgh_local_port;
mach_port_t dest_name, reply_name;
unsigned long payload;
+ int have_payload;
/* receiving a request message */
@@ -1018,6 +1019,8 @@ mach_msg_trap(
else
dest_name = MACH_PORT_NULL;
payload = dest_port->ip_protected_payload;
+ have_payload =
+ ipc_port_flag_protected_payload(dest_port);
if ((--dest_port->ip_srights == 0) &&
(dest_port->ip_nsrequest != IP_NULL)) {
@@ -1035,7 +1038,7 @@ mach_msg_trap(
} else
ip_unlock(dest_port);
- if (! ipc_port_flag_protected_payload(dest_port)) {
+ if (! have_payload) {
kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS(
MACH_MSG_TYPE_PORT_SEND_ONCE,
MACH_MSG_TYPE_PORT_SEND);
@@ -1059,6 +1062,7 @@ mach_msg_trap(
case MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE, 0): {
mach_port_t dest_name;
unsigned long payload;
+ int have_payload;
/* receiving a reply message */
@@ -1071,6 +1075,8 @@ mach_msg_trap(
assert(dest_port->ip_sorights > 0);
payload = dest_port->ip_protected_payload;
+ have_payload =
+ ipc_port_flag_protected_payload(dest_port);
if (dest_port->ip_receiver == space) {
ip_release(dest_port);
@@ -1084,7 +1090,7 @@ mach_msg_trap(
dest_name = MACH_PORT_NULL;
}
- if (! ipc_port_flag_protected_payload(dest_port)) {
+ if (! have_payload) {
kmsg->ikm_header.msgh_bits = MACH_MSGH_BITS(
0,
MACH_MSG_TYPE_PORT_SEND_ONCE);
@@ -1104,6 +1110,7 @@ mach_msg_trap(
MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND_ONCE, 0): {
mach_port_t dest_name;
unsigned long payload;
+ int have_payload;
/* receiving a complex reply message */
@@ -1116,6 +1123,9 @@ mach_msg_trap(
assert(dest_port->ip_sorights > 0);
payload = dest_port->ip_protected_payload;
+ have_payload =
+ ipc_port_flag_protected_payload(dest_port);
+
if (dest_port->ip_receiver == space) {
ip_release(dest_port);
@@ -1129,7 +1139,7 @@ mach_msg_trap(
dest_name = MACH_PORT_NULL;
}
- if (! ipc_port_flag_protected_payload(dest_port)) {
+ if (! have_payload) {
kmsg->ikm_header.msgh_bits =
MACH_MSGH_BITS_COMPLEX
| MACH_MSGH_BITS(
--
2.1.4
|
