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authorAlexey Dobriyan <adobriyan@gmail.com>2018-04-20 14:56:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-20 17:18:35 -0700
commit2e0ad552f5f8cd0fda02bc45fcd2b89821c62fd1 (patch)
tree1b22f2e03dc3d0e82048a454b3daeb5e54efd11b
parent1e6306652ba18723015d1b4967fe9de55f042499 (diff)
downloadlinux-stericsson-2e0ad552f5f8cd0fda02bc45fcd2b89821c62fd1.tar.gz
proc: revalidate kernel thread inodes to root:root
task_dump_owner() has the following code: mm = task->mm; if (mm) { if (get_dumpable(mm) != SUID_DUMP_USER) { uid = ... } } Check for ->mm is buggy -- kernel thread might be borrowing mm and inode will go to some random uid:gid pair. Link: http://lkml.kernel.org/r/20180412220109.GA20978@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/base.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index eafa39a3a88c..1b2ede6abcdf 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1693,6 +1693,12 @@ void task_dump_owner(struct task_struct *task, umode_t mode,
kuid_t uid;
kgid_t gid;
+ if (unlikely(task->flags & PF_KTHREAD)) {
+ *ruid = GLOBAL_ROOT_UID;
+ *rgid = GLOBAL_ROOT_GID;
+ return;
+ }
+
/* Default to the tasks effective ownership */
rcu_read_lock();
cred = __task_cred(task);