diff options
Diffstat (limited to 'include/linux/mnt_idmapping.h')
| -rw-r--r-- | include/linux/mnt_idmapping.h | 305 |
1 files changed, 273 insertions, 32 deletions
diff --git a/include/linux/mnt_idmapping.h b/include/linux/mnt_idmapping.h index ee5a217de2a8..f6e5369d2928 100644 --- a/include/linux/mnt_idmapping.h +++ b/include/linux/mnt_idmapping.h @@ -13,6 +13,129 @@ struct user_namespace; */ extern struct user_namespace init_user_ns; +typedef struct { + uid_t val; +} vfsuid_t; + +typedef struct { + gid_t val; +} vfsgid_t; + +static_assert(sizeof(vfsuid_t) == sizeof(kuid_t)); +static_assert(sizeof(vfsgid_t) == sizeof(kgid_t)); +static_assert(offsetof(vfsuid_t, val) == offsetof(kuid_t, val)); +static_assert(offsetof(vfsgid_t, val) == offsetof(kgid_t, val)); + +#ifdef CONFIG_MULTIUSER +static inline uid_t __vfsuid_val(vfsuid_t uid) +{ + return uid.val; +} + +static inline gid_t __vfsgid_val(vfsgid_t gid) +{ + return gid.val; +} +#else +static inline uid_t __vfsuid_val(vfsuid_t uid) +{ + return 0; +} + +static inline gid_t __vfsgid_val(vfsgid_t gid) +{ + return 0; +} +#endif + +static inline bool vfsuid_valid(vfsuid_t uid) +{ + return __vfsuid_val(uid) != (uid_t)-1; +} + +static inline bool vfsgid_valid(vfsgid_t gid) +{ + return __vfsgid_val(gid) != (gid_t)-1; +} + +static inline bool vfsuid_eq(vfsuid_t left, vfsuid_t right) +{ + return vfsuid_valid(left) && __vfsuid_val(left) == __vfsuid_val(right); +} + +static inline bool vfsgid_eq(vfsgid_t left, vfsgid_t right) +{ + return vfsgid_valid(left) && __vfsgid_val(left) == __vfsgid_val(right); +} + +/** + * vfsuid_eq_kuid - check whether kuid and vfsuid have the same value + * @vfsuid: the vfsuid to compare + * @kuid: the kuid to compare + * + * Check whether @vfsuid and @kuid have the same values. + * + * Return: true if @vfsuid and @kuid have the same value, false if not. + * Comparison between two invalid uids returns false. + */ +static inline bool vfsuid_eq_kuid(vfsuid_t vfsuid, kuid_t kuid) +{ + return vfsuid_valid(vfsuid) && __vfsuid_val(vfsuid) == __kuid_val(kuid); +} + +/** + * vfsgid_eq_kgid - check whether kgid and vfsgid have the same value + * @vfsgid: the vfsgid to compare + * @kgid: the kgid to compare + * + * Check whether @vfsgid and @kgid have the same values. + * + * Return: true if @vfsgid and @kgid have the same value, false if not. + * Comparison between two invalid gids returns false. + */ +static inline bool vfsgid_eq_kgid(vfsgid_t vfsgid, kgid_t kgid) +{ + return vfsgid_valid(vfsgid) && __vfsgid_val(vfsgid) == __kgid_val(kgid); +} + +/* + * vfs{g,u}ids are created from k{g,u}ids. + * We don't allow them to be created from regular {u,g}id. + */ +#define VFSUIDT_INIT(val) (vfsuid_t){ __kuid_val(val) } +#define VFSGIDT_INIT(val) (vfsgid_t){ __kgid_val(val) } + +#define INVALID_VFSUID VFSUIDT_INIT(INVALID_UID) +#define INVALID_VFSGID VFSGIDT_INIT(INVALID_GID) + +/* + * Allow a vfs{g,u}id to be used as a k{g,u}id where we want to compare + * whether the mapped value is identical to value of a k{g,u}id. + */ +#define AS_KUIDT(val) (kuid_t){ __vfsuid_val(val) } +#define AS_KGIDT(val) (kgid_t){ __vfsgid_val(val) } + +#ifdef CONFIG_MULTIUSER +/** + * vfsgid_in_group_p() - check whether a vfsuid matches the caller's groups + * @vfsgid: the mnt gid to match + * + * This function can be used to determine whether @vfsuid matches any of the + * caller's groups. + * + * Return: 1 if vfsuid matches caller's groups, 0 if not. + */ +static inline int vfsgid_in_group_p(vfsgid_t vfsgid) +{ + return in_group_p(AS_KGIDT(vfsgid)); +} +#else +static inline int vfsgid_in_group_p(vfsgid_t vfsgid) +{ + return 1; +} +#endif + /** * initial_idmapping - check whether this is the initial mapping * @ns: idmapping to check @@ -48,7 +171,7 @@ static inline bool no_idmapping(const struct user_namespace *mnt_userns, } /** - * mapped_kuid_fs - map a filesystem kuid into a mnt_userns + * make_vfsuid - map a filesystem kuid into a mnt_userns * @mnt_userns: the mount's idmapping * @fs_userns: the filesystem's idmapping * @kuid : kuid to be mapped @@ -67,25 +190,33 @@ static inline bool no_idmapping(const struct user_namespace *mnt_userns, * If @kuid has no mapping in either @mnt_userns or @fs_userns INVALID_UID is * returned. */ -static inline kuid_t mapped_kuid_fs(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - kuid_t kuid) + +static inline vfsuid_t make_vfsuid(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kuid_t kuid) { uid_t uid; if (no_idmapping(mnt_userns, fs_userns)) - return kuid; + return VFSUIDT_INIT(kuid); if (initial_idmapping(fs_userns)) uid = __kuid_val(kuid); else uid = from_kuid(fs_userns, kuid); if (uid == (uid_t)-1) - return INVALID_UID; - return make_kuid(mnt_userns, uid); + return INVALID_VFSUID; + return VFSUIDT_INIT(make_kuid(mnt_userns, uid)); +} + +static inline kuid_t mapped_kuid_fs(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kuid_t kuid) +{ + return AS_KUIDT(make_vfsuid(mnt_userns, fs_userns, kuid)); } /** - * mapped_kgid_fs - map a filesystem kgid into a mnt_userns + * make_vfsgid - map a filesystem kgid into a mnt_userns * @mnt_userns: the mount's idmapping * @fs_userns: the filesystem's idmapping * @kgid : kgid to be mapped @@ -104,21 +235,56 @@ static inline kuid_t mapped_kuid_fs(struct user_namespace *mnt_userns, * If @kgid has no mapping in either @mnt_userns or @fs_userns INVALID_GID is * returned. */ -static inline kgid_t mapped_kgid_fs(struct user_namespace *mnt_userns, - struct user_namespace *fs_userns, - kgid_t kgid) + +static inline vfsgid_t make_vfsgid(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kgid_t kgid) { gid_t gid; if (no_idmapping(mnt_userns, fs_userns)) - return kgid; + return VFSGIDT_INIT(kgid); if (initial_idmapping(fs_userns)) gid = __kgid_val(kgid); else gid = from_kgid(fs_userns, kgid); if (gid == (gid_t)-1) - return INVALID_GID; - return make_kgid(mnt_userns, gid); + return INVALID_VFSGID; + return VFSGIDT_INIT(make_kgid(mnt_userns, gid)); +} + +static inline kgid_t mapped_kgid_fs(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + kgid_t kgid) +{ + return AS_KGIDT(make_vfsgid(mnt_userns, fs_userns, kgid)); +} + +/** + * from_vfsuid - map a vfsuid into the filesystem idmapping + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @vfsuid : vfsuid to be mapped + * + * Map @vfsuid into the filesystem idmapping. This function has to be used in + * order to e.g. write @vfsuid to inode->i_uid. + * + * Return: @vfsuid mapped into the filesystem idmapping + */ +static inline kuid_t from_vfsuid(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + vfsuid_t vfsuid) +{ + uid_t uid; + + if (no_idmapping(mnt_userns, fs_userns)) + return AS_KUIDT(vfsuid); + uid = from_kuid(mnt_userns, AS_KUIDT(vfsuid)); + if (uid == (uid_t)-1) + return INVALID_UID; + if (initial_idmapping(fs_userns)) + return KUIDT_INIT(uid); + return make_kuid(fs_userns, uid); } /** @@ -145,16 +311,66 @@ static inline kuid_t mapped_kuid_user(struct user_namespace *mnt_userns, struct user_namespace *fs_userns, kuid_t kuid) { - uid_t uid; + return from_vfsuid(mnt_userns, fs_userns, VFSUIDT_INIT(kuid)); +} + +/** + * vfsuid_has_fsmapping - check whether a vfsuid maps into the filesystem + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @vfsuid: vfsuid to be mapped + * + * Check whether @vfsuid has a mapping in the filesystem idmapping. Use this + * function to check whether the filesystem idmapping has a mapping for + * @vfsuid. + * + * Return: true if @vfsuid has a mapping in the filesystem, false if not. + */ +static inline bool vfsuid_has_fsmapping(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + vfsuid_t vfsuid) +{ + return uid_valid(from_vfsuid(mnt_userns, fs_userns, vfsuid)); +} + +/** + * vfsuid_into_kuid - convert vfsuid into kuid + * @vfsuid: the vfsuid to convert + * + * This can be used when a vfsuid is committed as a kuid. + * + * Return: a kuid with the value of @vfsuid + */ +static inline kuid_t vfsuid_into_kuid(vfsuid_t vfsuid) +{ + return AS_KUIDT(vfsuid); +} + +/** + * from_vfsgid - map a vfsgid into the filesystem idmapping + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @vfsgid : vfsgid to be mapped + * + * Map @vfsgid into the filesystem idmapping. This function has to be used in + * order to e.g. write @vfsgid to inode->i_gid. + * + * Return: @vfsgid mapped into the filesystem idmapping + */ +static inline kgid_t from_vfsgid(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + vfsgid_t vfsgid) +{ + gid_t gid; if (no_idmapping(mnt_userns, fs_userns)) - return kuid; - uid = from_kuid(mnt_userns, kuid); - if (uid == (uid_t)-1) - return INVALID_UID; + return AS_KGIDT(vfsgid); + gid = from_kgid(mnt_userns, AS_KGIDT(vfsgid)); + if (gid == (gid_t)-1) + return INVALID_GID; if (initial_idmapping(fs_userns)) - return KUIDT_INIT(uid); - return make_kuid(fs_userns, uid); + return KGIDT_INIT(gid); + return make_kgid(fs_userns, gid); } /** @@ -181,16 +397,39 @@ static inline kgid_t mapped_kgid_user(struct user_namespace *mnt_userns, struct user_namespace *fs_userns, kgid_t kgid) { - gid_t gid; + return from_vfsgid(mnt_userns, fs_userns, VFSGIDT_INIT(kgid)); +} - if (no_idmapping(mnt_userns, fs_userns)) - return kgid; - gid = from_kgid(mnt_userns, kgid); - if (gid == (gid_t)-1) - return INVALID_GID; - if (initial_idmapping(fs_userns)) - return KGIDT_INIT(gid); - return make_kgid(fs_userns, gid); +/** + * vfsgid_has_fsmapping - check whether a vfsgid maps into the filesystem + * @mnt_userns: the mount's idmapping + * @fs_userns: the filesystem's idmapping + * @vfsgid: vfsgid to be mapped + * + * Check whether @vfsgid has a mapping in the filesystem idmapping. Use this + * function to check whether the filesystem idmapping has a mapping for + * @vfsgid. + * + * Return: true if @vfsgid has a mapping in the filesystem, false if not. + */ +static inline bool vfsgid_has_fsmapping(struct user_namespace *mnt_userns, + struct user_namespace *fs_userns, + vfsgid_t vfsgid) +{ + return gid_valid(from_vfsgid(mnt_userns, fs_userns, vfsgid)); +} + +/** + * vfsgid_into_kgid - convert vfsgid into kgid + * @vfsgid: the vfsgid to convert + * + * This can be used when a vfsgid is committed as a kgid. + * + * Return: a kgid with the value of @vfsgid + */ +static inline kgid_t vfsgid_into_kgid(vfsgid_t vfsgid) +{ + return AS_KGIDT(vfsgid); } /** @@ -209,7 +448,8 @@ static inline kgid_t mapped_kgid_user(struct user_namespace *mnt_userns, static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns, struct user_namespace *fs_userns) { - return mapped_kuid_user(mnt_userns, fs_userns, current_fsuid()); + return from_vfsuid(mnt_userns, fs_userns, + VFSUIDT_INIT(current_fsuid())); } /** @@ -228,7 +468,8 @@ static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns, static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns, struct user_namespace *fs_userns) { - return mapped_kgid_user(mnt_userns, fs_userns, current_fsgid()); + return from_vfsgid(mnt_userns, fs_userns, + VFSGIDT_INIT(current_fsgid())); } #endif /* _LINUX_MNT_IDMAPPING_H */ |