Messages in this thread Patch in this message | | | From | David Herrmann <> | Subject | [PATCH 7/9] kdbus: consolidate common code | Date | Thu, 6 Aug 2015 10:21:26 +0200 |
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Move the file-credential checkers into kdbus_ep_*() helper functions to avoid hard-coding the same behavior in multiple places.
Signed-off-by: David Herrmann <dh.herrmann@gmail.com> --- ipc/kdbus/connection.c | 20 ++------------------ ipc/kdbus/endpoint.c | 28 ++++++++++++++++++++++++++++ ipc/kdbus/endpoint.h | 3 +++ ipc/kdbus/handle.c | 8 +------- 4 files changed, 34 insertions(+), 25 deletions(-)
diff --git a/ipc/kdbus/connection.c b/ipc/kdbus/connection.c index c81888e..aa3296e 100644 --- a/ipc/kdbus/connection.c +++ b/ipc/kdbus/connection.c @@ -84,24 +84,8 @@ static struct kdbus_conn *kdbus_conn_new(struct kdbus_ep *ep, struct kdbus_bloom_parameter bloom; } bloom_item; - /* - * A connection is considered privileged, if, and only if, it didn't - * connect through a custom endpoint *and* it has CAP_IPC_OWNER on the - * namespace of the current domain. - * Additionally, a connection is considered equivalent to the bus owner - * if it didn't connect through a custom endpoint *and* it either is - * privileged or the same user as the bus owner. - * - * Bus owners and alike can bypass bus policies. Privileged connections - * can additionally change accounting, modify kernel resources and - * perform restricted operations, as long as they're privileged on the - * same level as the resources they touch. - */ - privileged = !ep->user && - file_ns_capable(file, ep->bus->domain->user_namespace, - CAP_IPC_OWNER); - owner = !ep->user && - (privileged || uid_eq(file->f_cred->euid, ep->bus->node.uid)); + privileged = kdbus_ep_is_privileged(ep, file); + owner = kdbus_ep_is_owner(ep, file); is_monitor = hello->flags & KDBUS_HELLO_MONITOR; is_activator = hello->flags & KDBUS_HELLO_ACTIVATOR; diff --git a/ipc/kdbus/endpoint.c b/ipc/kdbus/endpoint.c index 977964d..44e7a20 100644 --- a/ipc/kdbus/endpoint.c +++ b/ipc/kdbus/endpoint.c @@ -184,6 +184,34 @@ struct kdbus_ep *kdbus_ep_unref(struct kdbus_ep *ep) } /** + * kdbus_ep_is_privileged() - check whether a file is privileged + * @ep: endpoint to operate on + * @file: file to test + * + * Return: True if @file is privileged in the domain of @ep. + */ +bool kdbus_ep_is_privileged(struct kdbus_ep *ep, struct file *file) +{ + return !ep->user && + file_ns_capable(file, ep->bus->domain->user_namespace, + CAP_IPC_OWNER); +} + +/** + * kdbus_ep_is_owner() - check whether a file should be treated as bus owner + * @ep: endpoint to operate on + * @file: file to test + * + * Return: True if @file should be treated as bus owner on @ep + */ +bool kdbus_ep_is_owner(struct kdbus_ep *ep, struct file *file) +{ + return !ep->user && + (uid_eq(file->f_cred->euid, ep->bus->node.uid) || + kdbus_ep_is_privileged(ep, file)); +} + +/** * kdbus_cmd_ep_make() - handle KDBUS_CMD_ENDPOINT_MAKE * @bus: bus to operate on * @argp: command payload diff --git a/ipc/kdbus/endpoint.h b/ipc/kdbus/endpoint.h index bc1b94a..e0da59f 100644 --- a/ipc/kdbus/endpoint.h +++ b/ipc/kdbus/endpoint.h @@ -61,6 +61,9 @@ struct kdbus_ep *kdbus_ep_new(struct kdbus_bus *bus, const char *name, struct kdbus_ep *kdbus_ep_ref(struct kdbus_ep *ep); struct kdbus_ep *kdbus_ep_unref(struct kdbus_ep *ep); +bool kdbus_ep_is_privileged(struct kdbus_ep *ep, struct file *file); +bool kdbus_ep_is_owner(struct kdbus_ep *ep, struct file *file); + struct kdbus_ep *kdbus_cmd_ep_make(struct kdbus_bus *bus, void __user *argp); int kdbus_cmd_ep_update(struct kdbus_ep *ep, void __user *argp); diff --git a/ipc/kdbus/handle.c b/ipc/kdbus/handle.c index 4d41ecf..fc60932 100644 --- a/ipc/kdbus/handle.c +++ b/ipc/kdbus/handle.c @@ -395,14 +395,8 @@ static long kdbus_handle_ioctl_ep(struct file *file, unsigned int cmd, switch (cmd) { case KDBUS_CMD_ENDPOINT_MAKE: { - bool priv; - - priv = uid_eq(file->f_cred->euid, bus->node.uid) || - file_ns_capable(file, bus->domain->user_namespace, - CAP_IPC_OWNER); - /* creating custom endpoints is a privileged operation */ - if (file_ep->user || !priv) { + if (!kdbus_ep_is_owner(file_ep, file)) { ret = -EPERM; break; } -- 2.5.0
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