From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 819829f0319a759e8a6ccb7e4f1113f3f9f07aa3 ]
In preparation for new mount options to add lowerdirs one by one, generalize ovl_parse_param_upperdir() into helper ovl_parse_layer() that will be used for parsing a single lower layers.
Suggested-by: Miklos Szeredi miklos@szeredi.hu Link: https://lore.kernel.org/r/CAJfpegt7VC94KkRtb1dfHG8+4OzwPBLYqhtc8=QFUxpFJE+=R... Signed-off-by: Amir Goldstein amir73il@gmail.com Stable-dep-of: 2824083db76c ("ovl: Always reject mounting over case-insensitive directories") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/overlayfs/params.c | 121 +++++++++++++++++++++++------------------- 1 file changed, 67 insertions(+), 54 deletions(-)
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 0bf754a69e919..88725982b6dd3 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -43,7 +43,7 @@ module_param_named(metacopy, ovl_metacopy_def, bool, 0644); MODULE_PARM_DESC(metacopy, "Default to on or off for the metadata only copy up feature");
-enum { +enum ovl_opt { Opt_lowerdir, Opt_upperdir, Opt_workdir, @@ -238,19 +238,8 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) pr_err("failed to resolve '%s': %i\n", name, err); goto out; } - err = -EINVAL; - if (ovl_dentry_weird(path->dentry)) { - pr_err("filesystem on '%s' not supported\n", name); - goto out_put; - } - if (!d_is_dir(path->dentry)) { - pr_err("'%s' not a directory\n", name); - goto out_put; - } return 0;
-out_put: - path_put_init(path); out: return err; } @@ -268,7 +257,7 @@ static void ovl_unescape(char *s) } }
-static int ovl_mount_dir(const char *name, struct path *path, bool upper) +static int ovl_mount_dir(const char *name, struct path *path) { int err = -ENOMEM; char *tmp = kstrdup(name, GFP_KERNEL); @@ -276,60 +265,82 @@ static int ovl_mount_dir(const char *name, struct path *path, bool upper) if (tmp) { ovl_unescape(tmp); err = ovl_mount_dir_noesc(tmp, path); - - if (!err && upper && path->dentry->d_flags & DCACHE_OP_REAL) { - pr_err("filesystem on '%s' not supported as upperdir\n", - tmp); - path_put_init(path); - err = -EINVAL; - } kfree(tmp); } return err; }
-static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc, - bool workdir) +static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path, + enum ovl_opt layer, const char *name, bool upper) { - int err; - struct ovl_fs *ofs = fc->s_fs_info; - struct ovl_config *config = &ofs->config; - struct ovl_fs_context *ctx = fc->fs_private; - struct path path; - char *dup; + if (ovl_dentry_weird(path->dentry)) + return invalfc(fc, "filesystem on %s not supported", name);
- err = ovl_mount_dir(name, &path, true); - if (err) - return err; + if (!d_is_dir(path->dentry)) + return invalfc(fc, "%s is not a directory", name);
/* * Check whether upper path is read-only here to report failures * early. Don't forget to recheck when the superblock is created * as the mount attributes could change. */ - if (__mnt_is_readonly(path.mnt)) { - path_put(&path); - return -EINVAL; + if (upper) { + if (path->dentry->d_flags & DCACHE_OP_REAL) + return invalfc(fc, "filesystem on %s not supported as upperdir", name); + if (__mnt_is_readonly(path->mnt)) + return invalfc(fc, "filesystem on %s is read-only", name); } + return 0; +}
- dup = kstrdup(name, GFP_KERNEL); - if (!dup) { - path_put(&path); - return -ENOMEM; - } +static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer, + struct path *path, char **pname) +{ + struct ovl_fs *ofs = fc->s_fs_info; + struct ovl_config *config = &ofs->config; + struct ovl_fs_context *ctx = fc->fs_private;
- if (workdir) { - kfree(config->workdir); - config->workdir = dup; - path_put(&ctx->work); - ctx->work = path; - } else { - kfree(config->upperdir); - config->upperdir = dup; - path_put(&ctx->upper); - ctx->upper = path; + switch (layer) { + case Opt_workdir: + swap(config->workdir, *pname); + swap(ctx->work, *path); + break; + case Opt_upperdir: + swap(config->upperdir, *pname); + swap(ctx->upper, *path); + break; + default: + WARN_ON(1); } - return 0; +} + +static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param, + enum ovl_opt layer) +{ + char *name = kstrdup(param->string, GFP_KERNEL); + bool upper = (layer == Opt_upperdir || layer == Opt_workdir); + struct path path; + int err; + + if (!name) + return -ENOMEM; + + err = ovl_mount_dir(name, &path); + if (err) + goto out_free; + + err = ovl_mount_dir_check(fc, &path, layer, name, upper); + if (err) + goto out_put; + + /* Store the user provided path string in ctx to show in mountinfo */ + ovl_add_layer(fc, layer, &path, &name); + +out_put: + path_put(&path); +out_free: + kfree(name); + return err; }
static void ovl_reset_lowerdirs(struct ovl_fs_context *ctx) @@ -417,7 +428,11 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc) for (nr = 0; nr < nr_lower; nr++, l++) { memset(l, 0, sizeof(*l));
- err = ovl_mount_dir(iter, &l->path, false); + err = ovl_mount_dir(iter, &l->path); + if (err) + goto out_put; + + err = ovl_mount_dir_check(fc, &l->path, Opt_lowerdir, iter, false); if (err) goto out_put;
@@ -505,10 +520,8 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param) err = ovl_parse_param_lowerdir(param->string, fc); break; case Opt_upperdir: - fallthrough; case Opt_workdir: - err = ovl_parse_param_upperdir(param->string, fc, - (Opt_workdir == opt)); + err = ovl_parse_layer(fc, param, opt); break; case Opt_default_permissions: config->default_permissions = true;