Add LSM hooks for use by the superblock configuration context code.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
include/linux/lsm_hooks.h | 39 ++++++++++
include/linux/security.h | 28 +++++++
security/security.c | 25 +++++++
security/selinux/hooks.c | 169 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 261 insertions(+)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 080f34e66017..c2bbd9e92b0a 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -75,6 +75,34 @@
* should enable secure mode.
* @bprm contains the linux_binprm structure.
*
+ * Security hooks for mount using fd context.
+ *
+ * @sb_config_alloc:
+ * Allocate and attach a security structure to sc->security. This pointer
+ * is initialised to NULL by the caller.
+ * @sc indicates the new superblock configuration context.
+ * @src_sb indicates the source superblock of a submount.
+ * @sb_config_dup:
+ * Allocate and attach a security structure to sc->security. This pointer
+ * is initialised to NULL by the caller.
+ * @sc indicates the new superblock configuration context.
+ * @src_sc indicates the original superblock configuration context.
+ * @sb_config_free:
+ * Clean up a superblock configuration context.
+ * @sc indicates the superblock configuration context.
+ * @sb_config_parse_option:
+ * Userspace provided an option to configure a superblock. The LSM may
+ * reject it with an error and may use it for itself, in which case it
+ * should return 1; otherwise it should return 0 to pass it on to the
+ * filesystem.
+ * @sc indicates the superblock configuration context.
+ * @p indicates the option in "key[=val]" form.
+ * @sb_get_tree:
+ * Assign the security to a newly created superblock.
+ * @sc indicates the superblock configuration context.
+ * @sc->root indicates the root that will be mounted.
+ * @sc->root->d_sb points to the superblock.
+ *
* Security hooks for filesystem operations.
*
* @sb_alloc_security:
@@ -1372,6 +1400,12 @@ union security_list_options {
void (*bprm_committing_creds)(struct linux_binprm *bprm);
void (*bprm_committed_creds)(struct linux_binprm *bprm);
+ int (*sb_config_alloc)(struct sb_config *sc, struct super_block *src_sb);
+ int (*sb_config_dup)(struct sb_config *sc, struct sb_config *src_sc);
+ void (*sb_config_free)(struct sb_config *sc);
+ int (*sb_config_parse_option)(struct sb_config *sc, char *opt);
+ int (*sb_get_tree)(struct sb_config *sc);
+
int (*sb_alloc_security)(struct super_block *sb);
void (*sb_free_security)(struct super_block *sb);
int (*sb_copy_data)(char *orig, char *copy);
@@ -1683,6 +1717,11 @@ struct security_hook_heads {
struct list_head bprm_secureexec;
struct list_head bprm_committing_creds;
struct list_head bprm_committed_creds;
+ struct list_head sb_config_alloc;
+ struct list_head sb_config_dup;
+ struct list_head sb_config_free;
+ struct list_head sb_config_parse_option;
+ struct list_head sb_get_tree;
struct list_head sb_alloc_security;
struct list_head sb_free_security;
struct list_head sb_copy_data;
diff --git a/include/linux/security.h b/include/linux/security.h
index af675b576645..d1dfb6abd4f7 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -55,6 +55,7 @@ struct msg_queue;
struct xattr;
struct xfrm_sec_ctx;
struct mm_struct;
+struct sb_config;
/* If capable should audit the security request */
#define SECURITY_CAP_NOAUDIT 0
@@ -224,6 +225,11 @@ 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_bprm_secureexec(struct linux_binprm *bprm);
+int security_sb_config_alloc(struct sb_config *sc, struct super_block *sb);
+int security_sb_config_dup(struct sb_config *sc, struct sb_config *src_sc);
+void security_sb_config_free(struct sb_config *sc);
+int security_sb_config_parse_option(struct sb_config *sc, char *opt);
+int security_sb_get_tree(struct sb_config *sc);
int security_sb_alloc(struct super_block *sb);
void security_sb_free(struct super_block *sb);
int security_sb_copy_data(char *orig, char *copy);
@@ -520,6 +526,28 @@ static inline int security_bprm_secureexec(struct linux_binprm *bprm)
return cap_bprm_secureexec(bprm);
}
+static inline int security_sb_config_alloc(struct sb_config *sc,
+ struct super_block *src_sb)
+{
+ return 0;
+}
+static inline int security_sb_config_dup(struct sb_config *sc,
+ struct sb_config *src_sc)
+{
+ return 0;
+}
+static inline void security_sb_config_free(struct sb_config *sc)
+{
+}
+static inline int security_sb_config_parse_option(struct sb_config *sc, char *opt)
+{
+ return 0;
+}
+static inline int security_sb_get_tree(struct sb_config *sc)
+{
+ return 0;
+}
+
static inline int security_sb_alloc(struct super_block *sb)
{
return 0;
diff --git a/security/security.c b/security/security.c
index b9fea3999cf8..951f28487719 100644
--- a/security/security.c
+++ b/security/security.c
@@ -316,6 +316,31 @@ int security_bprm_secureexec(struct linux_binprm *bprm)
return call_int_hook(bprm_secureexec, 0, bprm);
}
+int security_sb_config_alloc(struct sb_config *sc, struct super_block *src_sb)
+{
+ return call_int_hook(sb_config_alloc, 0, sc, src_sb);
+}
+
+int security_sb_config_dup(struct sb_config *sc, struct sb_config *src_sc)
+{
+ return call_int_hook(sb_config_dup, 0, sc, src_sc);
+}
+
+void security_sb_config_free(struct sb_config *sc)
+{
+ call_void_hook(sb_config_free, sc);
+}
+
+int security_sb_config_parse_option(struct sb_config *sc, char *opt)
+{
+ return call_int_hook(sb_config_parse_option, 0, sc, opt);
+}
+
+int security_sb_get_tree(struct sb_config *sc)
+{
+ return call_int_hook(sb_get_tree, 0, sc);
+}
+
int security_sb_alloc(struct super_block *sb)
{
return call_int_hook(sb_alloc_security, 0, sb);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e67a526d1f30..420bfa955fb4 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -47,6 +47,7 @@
#include <linux/fdtable.h>
#include <linux/namei.h>
#include <linux/mount.h>
+#include <linux/sb_config.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/tty.h>
@@ -2826,6 +2827,168 @@ static int selinux_umount(struct vfsmount *mnt, int flags)
FILESYSTEM__UNMOUNT, NULL);
}
+/* fsopen mount context operations */
+
+static int selinux_sb_config_alloc(struct sb_config *sc,
+ struct super_block *src_sb)
+{
+ struct security_mnt_opts *opts;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+
+ sc->security = opts;
+ return 0;
+}
+
+static int selinux_sb_config_dup(struct sb_config *sc,
+ struct sb_config *src_sc)
+{
+ const struct security_mnt_opts *src = src_sc->security;
+ struct security_mnt_opts *opts;
+ int i, n;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+ sc->security = opts;
+
+ if (!src || !src->num_mnt_opts)
+ return 0;
+ n = opts->num_mnt_opts = src->num_mnt_opts;
+
+ if (src->mnt_opts) {
+ opts->mnt_opts = kcalloc(n, sizeof(char *), GFP_KERNEL);
+ if (!opts->mnt_opts)
+ return -ENOMEM;
+
+ for (i = 0; i < n; i++) {
+ if (src->mnt_opts[i]) {
+ opts->mnt_opts[i] = kstrdup(src->mnt_opts[i],
+ GFP_KERNEL);
+ if (!opts->mnt_opts[i])
+ return -ENOMEM;
+ }
+ }
+ }
+
+ if (src->mnt_opts_flags) {
+ opts->mnt_opts_flags = kmemdup(src->mnt_opts_flags,
+ n * sizeof(int), GFP_KERNEL);
+ if (!opts->mnt_opts_flags)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void selinux_sb_config_free(struct sb_config *sc)
+{
+ struct security_mnt_opts *opts = sc->security;
+
+ security_free_mnt_opts(opts);
+ sc->security = NULL;
+}
+
+static int selinux_sb_config_parse_option(struct sb_config *sc, char *opt)
+{
+ struct security_mnt_opts *opts = sc->security;
+ substring_t args[MAX_OPT_ARGS];
+ unsigned int have;
+ char *c, **oo;
+ int token, ctx, i, *of;
+
+ token = match_token(opt, tokens, args);
+ if (token == Opt_error)
+ return 0; /* Doesn't belong to us. */
+
+ have = 0;
+ for (i = 0; i < opts->num_mnt_opts; i++)
+ have |= 1 << opts->mnt_opts_flags[i];
+ if (have & (1 << token))
+ return invalf("SELinux: Duplicate mount options");
+
+ switch (token) {
+ case Opt_context:
+ if (have & (1 << Opt_defcontext))
+ goto incompatible;
+ ctx = CONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_fscontext:
+ ctx = FSCONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_rootcontext:
+ ctx = ROOTCONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_defcontext:
+ if (have & (1 << Opt_context))
+ goto incompatible;
+ ctx = DEFCONTEXT_MNT;
+ goto copy_context_string;
+
+ case Opt_labelsupport:
+ return 1;
+
+ default:
+ return invalf("SELinux: Unknown mount option");
+ }
+
+copy_context_string:
+ if (opts->num_mnt_opts > 3)
+ return invalf("SELinux: Too many options");
+
+ of = krealloc(opts->mnt_opts_flags,
+ (opts->num_mnt_opts + 1) * sizeof(int), GFP_KERNEL);
+ if (!of)
+ return -ENOMEM;
+ of[opts->num_mnt_opts] = 0;
+ opts->mnt_opts_flags = of;
+
+ oo = krealloc(opts->mnt_opts,
+ (opts->num_mnt_opts + 1) * sizeof(char *), GFP_KERNEL);
+ if (!oo)
+ return -ENOMEM;
+ oo[opts->num_mnt_opts] = NULL;
+ opts->mnt_opts = oo;
+
+ c = match_strdup(&args[0]);
+ if (!c)
+ return -ENOMEM;
+ opts->mnt_opts[opts->num_mnt_opts] = c;
+ opts->mnt_opts_flags[opts->num_mnt_opts] = ctx;
+ opts->num_mnt_opts++;
+ return 1;
+
+incompatible:
+ return invalf("SELinux: Incompatible mount options");
+}
+
+static int selinux_sb_get_tree(struct sb_config *sc)
+{
+ const struct cred *cred = current_cred();
+ struct common_audit_data ad;
+ int rc;
+
+ rc = selinux_set_mnt_opts(sc->root->d_sb, sc->security, 0, NULL);
+ if (rc)
+ return rc;
+
+ /* Allow all mounts performed by the kernel */
+ if (sc->ms_flags & MS_KERNMOUNT)
+ return 0;
+
+ ad.type = LSM_AUDIT_DATA_DENTRY;
+ ad.u.dentry = sc->root;
+ rc = superblock_has_perm(cred, sc->root->d_sb, FILESYSTEM__MOUNT, &ad);
+ if (rc < 0)
+ errorf("SELinux: Mount of superblock not permitted");
+ return rc;
+}
+
/* inode security operations */
static int selinux_inode_alloc_security(struct inode *inode)
@@ -6154,6 +6317,12 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(bprm_committed_creds, selinux_bprm_committed_creds),
LSM_HOOK_INIT(bprm_secureexec, selinux_bprm_secureexec),
+ LSM_HOOK_INIT(sb_config_alloc, selinux_sb_config_alloc),
+ LSM_HOOK_INIT(sb_config_dup, selinux_sb_config_dup),
+ LSM_HOOK_INIT(sb_config_free, selinux_sb_config_free),
+ LSM_HOOK_INIT(sb_config_parse_option, selinux_sb_config_parse_option),
+ LSM_HOOK_INIT(sb_get_tree, selinux_sb_get_tree),
+
LSM_HOOK_INIT(sb_alloc_security, selinux_sb_alloc_security),
LSM_HOOK_INIT(sb_free_security, selinux_sb_free_security),
LSM_HOOK_INIT(sb_copy_data, selinux_sb_copy_data),
--
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