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| author |   Eric W. Biederman <ebiederm@xmission.com> | 2016-06-09 15:34:02 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2016-06-23 15:41:57 -0500 |
| commit | a2982cc922c3068783eb9a1f77a5626a1ec36a1f (patch) | |
| tree | 61ccc6ad01f8804d5290ae4565ba8d4238bf648a /fs/namei.c | |
| parent | ipc/mqueue: The mqueue filesystem should never contain executables (diff) | |
| download | wireguard-linux-a2982cc922c3068783eb9a1f77a5626a1ec36a1f.tar.xz wireguard-linux-a2982cc922c3068783eb9a1f77a5626a1ec36a1f.zip | |
vfs: Generalize filesystem nodev handling.
Introduce a function may_open_dev that tests MNT_NODEV and a new
superblock flab SB_I_NODEV. Use this new function in all of the
places where MNT_NODEV was previously tested.
Add the new SB_I_NODEV s_iflag to proc, sysfs, and mqueuefs as those
filesystems should never support device nodes, and a simple superblock
flags makes that very hard to get wrong. With SB_I_NODEV set if any
device nodes somehow manage to show up on on a filesystem those
device nodes will be unopenable.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/namei.c b/fs/namei.c index 6a82fb7e2127..757a32725d92 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2881,6 +2881,12 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, } EXPORT_SYMBOL(vfs_create); +bool may_open_dev(const struct path *path) +{ + return !(path->mnt->mnt_flags & MNT_NODEV) && + !(path->mnt->mnt_sb->s_iflags & SB_I_NODEV); +} + static int may_open(struct path *path, int acc_mode, int flag) { struct dentry *dentry = path->dentry; @@ -2899,7 +2905,7 @@ static int may_open(struct path *path, int acc_mode, int flag) break; case S_IFBLK: case S_IFCHR: - if (path->mnt->mnt_flags & MNT_NODEV) + if (!may_open_dev(path)) return -EACCES; /*FALLTHRU*/ case S_IFIFO: |