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authorAlexander Lochmann <alexander.lochmann@tu-dortmund.de>2018-12-14 11:55:52 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-06-22 08:17:24 +0200
commit77beb274790656702dbca6d1e698da522d56c069 (patch)
tree453aa5762c43d127dbf7542e7654ec7b11c01dca
parent7219a58c57de1b5046154c2267ac70f9fcdee6f8 (diff)
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> Cc: Zubin Mithra <zsm@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/inode.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 2071ff5343c5..30a97292e965 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1804,8 +1804,13 @@ 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);