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authorJann Horn <jannh@google.com>2016-06-25 01:51:52 +0200
committerMike Marshall <hubcap@omnibond.com>2016-07-05 15:47:43 -0400
commit78fee0b6846f27872321338db6afe280f059ae99 (patch)
tree6a892ab00e37596ab8bbde5b58732799af3c4616 /fs/orangefs/orangefs-kernel.h
parentOrangefs: allow O_DIRECT in open (diff)
downloadlinux-dev-78fee0b6846f27872321338db6afe280f059ae99.tar.xz
linux-dev-78fee0b6846f27872321338db6afe280f059ae99.zip
orangefs: fix namespace handling
In orangefs_inode_getxattr(), an fsuid is written to dmesg. The kuid is converted to a userspace uid via from_kuid(current_user_ns(), [...]), but since dmesg is global, init_user_ns should be used here instead. In copy_attributes_from_inode(), op_alloc() and fill_default_sys_attrs(), upcall structures are populated with uids/gids that have been mapped into the caller's namespace. However, those upcall structures are read by another process (the userspace filesystem driver), and that process might be running in another namespace. This effectively lets any user spoof its uid and gid as seen by the userspace filesystem driver. To fix the second issue, I just construct the opcall structures with init_user_ns uids/gids and require the filesystem server to run in the init namespace. Since orangefs is full of global state anyway (as the error message in DUMP_DEVICE_ERROR explains, there can only be one userspace orangefs filesystem driver at once), that shouldn't be a problem. [ Why does orangefs even exist in the kernel if everything does upcalls into userspace? What does orangefs do that couldn't be done with the FUSE interface? If there is no good answer to those questions, I'd prefer to see orangefs kicked out of the kernel. Can that be done for something that shipped in a release? According to commit f7ab093f74bf ("Orangefs: kernel client part 1"), they even already have a FUSE daemon, and the only rational reason (apart from "but most of our users report preferring to use our kernel module instead") given for not wanting to use FUSE is one "in-the-works" feature that could probably be integated into FUSE instead. ] This patch has been compile-tested. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Mike Marshall <hubcap@omnibond.com>
Diffstat (limited to 'fs/orangefs/orangefs-kernel.h')
-rw-r--r--fs/orangefs/orangefs-kernel.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
index 7b542f168d44..c1181e5529af 100644
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -587,8 +587,8 @@ int service_operation(struct orangefs_kernel_op_s *op,
#define fill_default_sys_attrs(sys_attr, type, mode) \
do { \
- sys_attr.owner = from_kuid(current_user_ns(), current_fsuid()); \
- sys_attr.group = from_kgid(current_user_ns(), current_fsgid()); \
+ sys_attr.owner = from_kuid(&init_user_ns, current_fsuid()); \
+ sys_attr.group = from_kgid(&init_user_ns, current_fsgid()); \
sys_attr.perms = ORANGEFS_util_translate_mode(mode); \
sys_attr.mtime = 0; \
sys_attr.atime = 0; \