Currently kdbus_domain_user_find_or_new() is used to find a user
domain or create a new one and link it into the domain.
kdbus_domain_user_find_or_new() may fail due to memory allocation
errors or if the domain was shutdown, but since callers will
receive only a NULL pointer on failure, they assume -ENOMEM and
ignore -ESHUTDOWN. Fix this in kdbus_domain_user_account() by returning
the appropriate error code.
There are also some races with kdbus_domain_user_find_or_new(), if it is
called with the same parameters and if we do not find a previously
linked domain user, then both threads will race to assign a different ID
for the same uid, thus, invalidating the users array. We fix this in the
new kdbus_domain_user_account() and __kdbus_domain_user_account() by
taking the domain lock only one time.
Replace some kdbus_domain_user_find_or_new() calls with
kdbus_domain_user_account(). The last one in bus.c is updated in the
next patch.
Signed-off-by: Djalal Harouni <tix...@opendz.org>
---
connection.c | 12 ++++++------
handle.c | 8 ++++----
2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/connection.c b/connection.c
index 1658a92..8838029 100644
--- a/connection.c
+++ b/connection.c
@@ -2092,12 +2092,12 @@ int kdbus_conn_new(struct kdbus_ep *ep,
*/
if (ep->user)
conn->user = kdbus_domain_user_ref(ep->user);
- else
- conn->user = kdbus_domain_user_find_or_new(ep->bus->domain,
- current_fsuid());
- if (!conn->user) {
- ret = -ENOMEM;
- goto exit_free_meta;
+ else {
+ ret = kdbus_domain_user_account(ep->bus->domain,
+ current_fsuid(),
+ &conn->user);
+ if (ret < 0)
+ goto exit_free_meta;
}
/* lock order: domain -> bus -> ep -> names -> conn */
diff --git a/handle.c b/handle.c
index bf32c6e..d8e1dc6 100644
--- a/handle.c
+++ b/handle.c
@@ -464,11 +464,11 @@ static long kdbus_handle_ioctl_ep(struct file *file,
unsigned int cmd,
* endpoint users do not share the budget with the ordinary
* users created for a UID.
*/
- ep->user = kdbus_domain_user_find_or_new(
- handle->ep->bus->domain, INVALID_UID);
- if (!ep->user) {
+ ret = kdbus_domain_user_account(
+ handle->ep->bus->domain,
+ INVALID_UID, &ep->user);
+ if (ret < 0) {
kdbus_ep_unref(ep);
- ret = -ENOMEM;
break;
}
--
1.9.3
_______________________________________________
systemd-devel mailing list
systemd-devel@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/systemd-devel
