diff options
| author | Lennart Poettering <lennart@poettering.net> | 2016-11-29 15:54:42 +0100 |
|---|---|---|
| committer | Sven Eden <yamakuzure@gmx.net> | 2017-07-17 17:58:35 +0200 |
| commit | 7b987da65ad4eacb30034519653a61457b688352 (patch) | |
| tree | f7479cac5978a07354bb971607c335f05d6f58d5 /src/basic | |
| parent | 5de3db0016e2a97b779abe27be5e7326ec1b78aa (diff) | |
fs-util: change chase_symlinks() behaviour in regards to escaping the root dir
Previously, we'd generate an EINVAL error if it is attempted to escape a root
directory with relative ".." symlinks. With this commit this is changed so that
".." from the root directory is a NOP, following the kernel's own behaviour
where /.. is equivalent to /.
As suggested by @keszybz.
Diffstat (limited to 'src/basic')
| -rw-r--r-- | src/basic/fs-util.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c index 39f840581..b97edb552 100644 --- a/src/basic/fs-util.c +++ b/src/basic/fs-util.c @@ -616,8 +616,8 @@ int chase_symlinks(const char *path, const char *_root, char **ret) { * symlinks relative to a root directory, instead of the root of the host. * * Note that "root" primarily matters if we encounter an absolute symlink. It is also used when following - * relative symlinks to ensure they cannot be used to "escape" the root directory. (For cases where this is - * attempted -EINVAL is returned.). The path parameter passed shall *not* be prefixed by it. + * relative symlinks to ensure they cannot be used to "escape" the root directory. The path parameter passed + * shall *not* be prefixed by it. * * Algorithmically this operates on two path buffers: "done" are the components of the path we already * processed and resolved symlinks, "." and ".." of. "todo" are the components of the path we still need to @@ -679,18 +679,20 @@ int chase_symlinks(const char *path, const char *_root, char **ret) { _cleanup_free_ char *parent = NULL; int fd_parent = -1; + /* If we already are at the top, then going up will not change anything. This is in-line with + * how the kernel handles this. */ if (isempty(done) || path_equal(done, "/")) - return -EINVAL; + continue; parent = dirname_malloc(done); if (!parent) return -ENOMEM; - /* Don't allow this to leave the root dir */ + /* Don't allow this to leave the root dir. */ if (root && path_startswith(done, root) && !path_startswith(parent, root)) - return -EINVAL; + continue; free_and_replace(done, parent); |