diff options
| author | Miklos Szeredi | 2016-09-16 12:44:20 +0200 |
|---|---|---|
| committer | Miklos Szeredi | 2016-09-16 12:44:20 +0200 |
| commit | f2b20f6ee842313a0d681dbbf7f87b70291a6a3b (patch) | |
| tree | b4bea4c83e1968a4f69592e9a7fc15be81750a8c /fs/attr.c | |
| parent | e71b9dff0634edb127f449e076e883ef24a8c76c (diff) | |
vfs: move permission checking into notify_change() for utimes(NULL)
This fixes a bug where the permission was not properly checked in
overlayfs. The testcase is ltp/utimensat01.
It is also cleaner and safer to do the permission checking in the vfs
helper instead of the caller.
This patch introduces an additional ia_valid flag ATTR_TOUCH (since
touch(1) is the most obvious user of utimes(NULL)) that is passed into
notify_change whenever the conditions for this special permission checking
mode are met.
Reported-by: Aihua Zhang <zhangaihua1@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Aihua Zhang <zhangaihua1@huawei.com>
Cc: <stable@vger.kernel.org> # v3.18+
Diffstat (limited to 'fs/attr.c')
| -rw-r--r-- | fs/attr.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/fs/attr.c b/fs/attr.c index 42bb42bb3c72..3c42cab06b5d 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -202,6 +202,21 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de return -EPERM; } + /* + * If utimes(2) and friends are called with times == NULL (or both + * times are UTIME_NOW), then we need to check for write permission + */ + if (ia_valid & ATTR_TOUCH) { + if (IS_IMMUTABLE(inode)) + return -EPERM; + + if (!inode_owner_or_capable(inode)) { + error = inode_permission(inode, MAY_WRITE); + if (error) + return error; + } + } + if ((ia_valid & ATTR_MODE)) { umode_t amode = attr->ia_mode; /* Flag setting protected by i_mutex */ |