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authorAlexander Lochmann <alexander.lochmann@tu-dortmund.de>2018-12-14 11:55:52 +0100
committerPaul Gortmaker <paul.gortmaker@windriver.com>2019-09-16 12:21:45 -0400
commite688ac750c0bf677ba9ac4bb306a82d288de862e (patch)
tree9ccccc754fc1062242c3b80533e97249b4e6f523
parenta94b12751ac67c3e8cb71be3966a1c724477e068 (diff)
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Abort file_remove_privs() for non-reg. files
commit f69e749a49353d96af1a293f56b5b56de59c668a upstream. file_remove_privs() might be called for non-regular files, e.g. blkdev inode. There is no reason to do its job on things like blkdev inodes, pipes, or cdevs. Hence, abort if file does not refer to a regular inode. AV: more to the point, for devices there might be any number of inodes refering to given device. Which one to strip the permissions from, even if that made any sense in the first place? All of them will be observed with contents modified, after all. Found by LockDoc (Alexander Lochmann, Horst Schirmeier and Olaf Spinczyk) Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Alexander Lochmann <alexander.lochmann@tu-dortmund.de> Signed-off-by: Horst Schirmeier <horst.schirmeier@tu-dortmund.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
-rw-r--r--fs/inode.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/inode.c b/fs/inode.c
index a06de4454232..81f33dcbd7a6 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1851,8 +1851,13 @@ int file_remove_privs(struct file *file)
int kill;
int error = 0;
- /* Fast path for nothing security related */
- if (IS_NOSEC(inode))
+ /*
+ * Fast path for nothing security related.
+ * As well for non-regular files, e.g. blkdev inodes.
+ * For example, blkdev_write_iter() might get here
+ * trying to remove privs which it is not allowed to.
+ */
+ if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode))
return 0;
kill = dentry_needs_remove_privs(dentry);