From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
new primitive: vfs_dup_fs_context(). Comes with fs_context
method (->dup()) for copying the filesystem-specific parts
of fs_context, along with LSM one (->fs_context_dup()) for
doing the same to LSM parts.
[needs better commit message, and change of Author:, anyway]
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/fs_context.c | 67 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs_context.h | 2 +
include/linux/lsm_hooks.h | 7 +++++
include/linux/security.h | 6 ++++
security/security.c | 5 +++
security/selinux/hooks.c | 39 ++++++++++++++++++++++++++
security/smack/smack_lsm.c | 49 ++++++++++++++++++++++++++++++++
7 files changed, 175 insertions(+)
diff --git a/fs/fs_context.c b/fs/fs_context.c
index aa7e0ffb591a..57f61833ac83 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -337,6 +337,47 @@ void fc_drop_locked(struct fs_context *fc)
static void legacy_fs_context_free(struct fs_context *fc);
+/**
+ * vfs_dup_fc_config: Duplicate a filesystem context.
+ * @src_fc: The context to copy.
+ */
+struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
+{
+ struct fs_context *fc;
+ int ret;
+
+ if (!src_fc->ops->dup)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ fc = kmemdup(src_fc, sizeof(struct fs_context), GFP_KERNEL);
+ if (!fc)
+ return ERR_PTR(-ENOMEM);
+
+ fc->fs_private = NULL;
+ fc->s_fs_info = NULL;
+ fc->source = NULL;
+ fc->security = NULL;
+ get_filesystem(fc->fs_type);
+ get_net(fc->net_ns);
+ get_user_ns(fc->user_ns);
+ get_cred(fc->cred);
+
+ /* Can't call put until we've called ->dup */
+ ret = fc->ops->dup(fc, src_fc);
+ if (ret < 0)
+ goto err_fc;
+
+ ret = security_fs_context_dup(fc, src_fc);
+ if (ret < 0)
+ goto err_fc;
+ return fc;
+
+err_fc:
+ put_fs_context(fc);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(vfs_dup_fs_context);
+
/**
* put_fs_context - Dispose of a superblock configuration context.
* @fc: The context to dispose of.
@@ -380,6 +421,31 @@ static void legacy_fs_context_free(struct fs_context *fc)
}
}
+/*
+ * Duplicate a legacy config.
+ */
+static int legacy_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
+{
+ struct legacy_fs_context *ctx;
+ struct legacy_fs_context *src_ctx = src_fc->fs_private;
+
+ ctx = kmemdup(src_ctx, sizeof(*src_ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+
+ if (ctx->param_type == LEGACY_FS_INDIVIDUAL_PARAMS) {
+ ctx->legacy_data = kmemdup(src_ctx->legacy_data,
+ src_ctx->data_size, GFP_KERNEL);
+ if (!ctx->legacy_data) {
+ kfree(ctx);
+ return -ENOMEM;
+ }
+ }
+
+ fc->fs_private = ctx;
+ return 0;
+}
+
/*
* Add a parameter to a legacy config. We build up a comma-separated list of
* options.
@@ -514,6 +580,7 @@ static int legacy_reconfigure(struct fs_context *fc)
const struct fs_context_operations legacy_fs_context_ops = {
.free = legacy_fs_context_free,
+ .dup = legacy_fs_context_dup,
.parse_param = legacy_parse_param,
.parse_monolithic = legacy_parse_monolithic,
.get_tree = legacy_get_tree,
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index b1a95db7a111..0db0b645c7b8 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -94,6 +94,7 @@ struct fs_context {
struct fs_context_operations {
void (*free)(struct fs_context *fc);
+ int (*dup)(struct fs_context *fc, struct fs_context *src_fc);
int (*parse_param)(struct fs_context *fc, struct fs_parameter *param);
int (*parse_monolithic)(struct fs_context *fc, void *data);
int (*get_tree)(struct fs_context *fc);
@@ -111,6 +112,7 @@ extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type,
struct dentry *reference);
+extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
const char *value, size_t v_size);
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 47ba4db4d8fb..356e78fe90a8 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -79,6 +79,11 @@
* Security hooks for mount using fs_context.
* [See also Documentation/filesystems/mounting.txt]
*
+ * @fs_context_dup:
+ * Allocate and attach a security structure to sc->security. This pointer
+ * is initialised to NULL by the caller.
+ * @fc indicates the new filesystem context.
+ * @src_fc indicates the original filesystem context.
* @fs_context_parse_param:
* Userspace provided a parameter to configure a superblock. The LSM may
* reject it with an error and may use it for itself, in which case it
@@ -1470,6 +1475,7 @@ union security_list_options {
void (*bprm_committing_creds)(struct linux_binprm *bprm);
void (*bprm_committed_creds)(struct linux_binprm *bprm);
+ int (*fs_context_dup)(struct fs_context *fc, struct fs_context *src_sc);
int (*fs_context_parse_param)(struct fs_context *fc, struct fs_parameter *param);
int (*sb_alloc_security)(struct super_block *sb);
@@ -1813,6 +1819,7 @@ struct security_hook_heads {
struct hlist_head bprm_check_security;
struct hlist_head bprm_committing_creds;
struct hlist_head bprm_committed_creds;
+ struct hlist_head fs_context_dup;
struct hlist_head fs_context_parse_param;
struct hlist_head sb_alloc_security;
struct hlist_head sb_free_security;
diff --git a/include/linux/security.h b/include/linux/security.h
index 2da9336a987e..f28a1ebfd78e 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -223,6 +223,7 @@ int security_bprm_set_creds(struct linux_binprm *bprm);
int security_bprm_check(struct linux_binprm *bprm);
void security_bprm_committing_creds(struct linux_binprm *bprm);
void security_bprm_committed_creds(struct linux_binprm *bprm);
+int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc);
int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param);
int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
@@ -521,6 +522,11 @@ static inline void security_bprm_committed_creds(struct linux_binprm *bprm)
{
}
+static inline int security_fs_context_dup(struct fs_context *fc,
+ struct fs_context *src_fc)
+{
+ return 0;
+}
static inline int security_fs_context_parse_param(struct fs_context *fc,
struct fs_parameter *param)
{
diff --git a/security/security.c b/security/security.c
index e5519488327d..5759339319dc 100644
--- a/security/security.c
+++ b/security/security.c
@@ -374,6 +374,11 @@ void security_bprm_committed_creds(struct linux_binprm *bprm)
call_void_hook(bprm_committed_creds, bprm);
}
+int security_fs_context_dup(struct fs_context *fc, struct fs_context *src_fc)
+{
+ return call_int_hook(fs_context_dup, 0, fc, src_fc);
+}
+
int security_fs_context_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
return call_int_hook(fs_context_parse_param, -ENOPARAM, fc, param);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f99381e97d73..4ba83de5fa80 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2764,6 +2764,44 @@ static int selinux_umount(struct vfsmount *mnt, int flags)
FILESYSTEM__UNMOUNT, NULL);
}
+static int selinux_fs_context_dup(struct fs_context *fc,
+ struct fs_context *src_fc)
+{
+ const struct selinux_mnt_opts *src = src_fc->security;
+ struct selinux_mnt_opts *opts;
+
+ if (!src)
+ return 0;
+
+ fc->security = kzalloc(sizeof(struct selinux_mnt_opts), GFP_KERNEL);
+ if (!fc->security)
+ return -ENOMEM;
+
+ opts = fc->security;
+
+ if (src->fscontext) {
+ opts->fscontext = kstrdup(src->fscontext, GFP_KERNEL);
+ if (!opts->fscontext)
+ return -ENOMEM;
+ }
+ if (src->context) {
+ opts->context = kstrdup(src->context, GFP_KERNEL);
+ if (!opts->context)
+ return -ENOMEM;
+ }
+ if (src->rootcontext) {
+ opts->rootcontext = kstrdup(src->rootcontext, GFP_KERNEL);
+ if (!opts->rootcontext)
+ return -ENOMEM;
+ }
+ if (src->defcontext) {
+ opts->defcontext = kstrdup(src->defcontext, GFP_KERNEL);
+ if (!opts->defcontext)
+ return -ENOMEM;
+ }
+ return 0;
+}
+
static const struct fs_parameter_spec selinux_param_specs[] = {
fsparam_string(CONTEXT_STR, Opt_context),
fsparam_string(DEFCONTEXT_STR, Opt_defcontext),
@@ -6745,6 +6783,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bprm_committing_creds, selinux_bprm_committing_creds),
LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),
+ LSM_HOOK_INIT(fs_context_dup, selinux_fs_context_dup),
LSM_HOOK_INIT(fs_context_parse_param, selinux_fs_context_parse_param),
LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security),
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 5f93c4f84384..03176f600a87 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -647,6 +647,54 @@ static int smack_add_opt(int token, const char *s, void **mnt_opts)
return -EINVAL;
}
+/**
+ * smack_fs_context_dup - Duplicate the security data on fs_context duplication
+ * @fc: The new filesystem context.
+ * @src_fc: The source filesystem context being duplicated.
+ *
+ * Returns 0 on success or -ENOMEM on error.
+ */
+static int smack_fs_context_dup(struct fs_context *fc,
+ struct fs_context *src_fc)
+{
+ struct smack_mnt_opts *dst, *src = src_fc->security;
+
+ if (!src)
+ return 0;
+
+ fc->security = kzalloc(sizeof(struct smack_mnt_opts), GFP_KERNEL);
+ if (!fc->security)
+ return -ENOMEM;
+ dst = fc->security;
+
+ if (src->fsdefault) {
+ dst->fsdefault = kstrdup(src->fsdefault, GFP_KERNEL);
+ if (!dst->fsdefault)
+ return -ENOMEM;
+ }
+ if (src->fsfloor) {
+ dst->fsfloor = kstrdup(src->fsfloor, GFP_KERNEL);
+ if (!dst->fsfloor)
+ return -ENOMEM;
+ }
+ if (src->fshat) {
+ dst->fshat = kstrdup(src->fshat, GFP_KERNEL);
+ if (!dst->fshat)
+ return -ENOMEM;
+ }
+ if (src->fsroot) {
+ dst->fsroot = kstrdup(src->fsroot, GFP_KERNEL);
+ if (!dst->fsroot)
+ return -ENOMEM;
+ }
+ if (src->fstransmute) {
+ dst->fstransmute = kstrdup(src->fstransmute, GFP_KERNEL);
+ if (!dst->fstransmute)
+ return -ENOMEM;
+ }
+ return 0;
+}
+
static const struct fs_parameter_spec smack_param_specs[] = {
fsparam_string("fsdefault", Opt_fsdefault),
fsparam_string("fsfloor", Opt_fsfloor),
@@ -4626,6 +4674,7 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
LSM_HOOK_INIT(syslog, smack_syslog),
+ LSM_HOOK_INIT(fs_context_dup, smack_fs_context_dup),
LSM_HOOK_INIT(fs_context_parse_param, smack_fs_context_parse_param),
LSM_HOOK_INIT(sb_alloc_security, smack_sb_alloc_security),
