diff --git a/fs/internal.h b/fs/internal.h index e7f02ae1e0981..db6094d5cb0b6 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -338,3 +338,4 @@ static inline bool path_mounted(const struct path *path) return path->mnt->mnt_root == path->dentry; } void file_f_owner_release(struct file *file); +int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map); diff --git a/fs/mnt_idmapping.c b/fs/mnt_idmapping.c index 7b1df8cc2821d..a37991fdb194d 100644 --- a/fs/mnt_idmapping.c +++ b/fs/mnt_idmapping.c @@ -6,6 +6,7 @@ #include #include #include +#include #include "internal.h" @@ -334,3 +335,53 @@ void mnt_idmap_put(struct mnt_idmap *idmap) free_mnt_idmap(idmap); } EXPORT_SYMBOL_GPL(mnt_idmap_put); + +int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map) +{ + struct uid_gid_map *map, *map_up; + u32 idx, nr_mappings; + + if (!is_valid_mnt_idmap(idmap)) + return 0; + + /* + * Idmappings are shown relative to the caller's idmapping. + * This is both the most intuitive and most useful solution. + */ + if (uid_map) { + map = &idmap->uid_map; + map_up = ¤t_user_ns()->uid_map; + } else { + map = &idmap->gid_map; + map_up = ¤t_user_ns()->gid_map; + } + + for (idx = 0, nr_mappings = 0; idx < map->nr_extents; idx++) { + uid_t lower; + struct uid_gid_extent *extent; + + if (map->nr_extents <= UID_GID_MAP_MAX_BASE_EXTENTS) + extent = &map->extent[idx]; + else + extent = &map->forward[idx]; + + /* + * Verify that the whole range of the mapping can be + * resolved in the caller's idmapping. If it cannot be + * resolved skip the mapping. + */ + lower = map_id_range_up(map_up, extent->lower_first, extent->count); + if (lower == (uid_t) -1) + continue; + + seq_printf(seq, "%u %u %u", extent->first, lower, extent->count); + + seq->count++; /* mappings are separated by \0 */ + if (seq_has_overflowed(seq)) + return -EAGAIN; + + nr_mappings++; + } + + return nr_mappings; +} diff --git a/fs/namespace.c b/fs/namespace.c index d470a369d42bc..967ee2a5bacf3 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -5008,6 +5008,7 @@ struct kstatmount { struct statmount __user *buf; size_t bufsize; struct vfsmount *mnt; + struct mnt_idmap *idmap; u64 mask; struct path root; struct statmount sm; @@ -5278,6 +5279,46 @@ static int statmount_opt_sec_array(struct kstatmount *s, struct seq_file *seq) return 0; } +static inline int statmount_mnt_uidmap(struct kstatmount *s, struct seq_file *seq) +{ + int ret; + + ret = statmount_mnt_idmap(s->idmap, seq, true); + if (ret < 0) + return ret; + + s->sm.mnt_uidmap_num = ret; + /* + * Always raise STATMOUNT_MNT_UIDMAP even if there are no valid + * mappings. This allows userspace to distinguish between a + * non-idmapped mount and an idmapped mount where none of the + * individual mappings are valid in the caller's idmapping. + */ + if (is_valid_mnt_idmap(s->idmap)) + s->sm.mask |= STATMOUNT_MNT_UIDMAP; + return 0; +} + +static inline int statmount_mnt_gidmap(struct kstatmount *s, struct seq_file *seq) +{ + int ret; + + ret = statmount_mnt_idmap(s->idmap, seq, false); + if (ret < 0) + return ret; + + s->sm.mnt_gidmap_num = ret; + /* + * Always raise STATMOUNT_MNT_GIDMAP even if there are no valid + * mappings. This allows userspace to distinguish between a + * non-idmapped mount and an idmapped mount where none of the + * individual mappings are valid in the caller's idmapping. + */ + if (is_valid_mnt_idmap(s->idmap)) + s->sm.mask |= STATMOUNT_MNT_GIDMAP; + return 0; +} + static int statmount_string(struct kstatmount *s, u64 flag) { int ret = 0; @@ -5319,6 +5360,14 @@ static int statmount_string(struct kstatmount *s, u64 flag) sm->sb_source = start; ret = statmount_sb_source(s, seq); break; + case STATMOUNT_MNT_UIDMAP: + sm->mnt_uidmap = start; + ret = statmount_mnt_uidmap(s, seq); + break; + case STATMOUNT_MNT_GIDMAP: + sm->mnt_gidmap = start; + ret = statmount_mnt_gidmap(s, seq); + break; default: WARN_ON_ONCE(true); return -EINVAL; @@ -5443,6 +5492,7 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id, return err; s->root = root; + s->idmap = mnt_idmap(s->mnt); if (s->mask & STATMOUNT_SB_BASIC) statmount_sb_basic(s); @@ -5476,6 +5526,12 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id, if (!err && s->mask & STATMOUNT_SB_SOURCE) err = statmount_string(s, STATMOUNT_SB_SOURCE); + if (!err && s->mask & STATMOUNT_MNT_UIDMAP) + err = statmount_string(s, STATMOUNT_MNT_UIDMAP); + + if (!err && s->mask & STATMOUNT_MNT_GIDMAP) + err = statmount_string(s, STATMOUNT_MNT_GIDMAP); + if (!err && s->mask & STATMOUNT_MNT_NS_ID) statmount_mnt_ns_id(s, ns); @@ -5499,7 +5555,8 @@ static inline bool retry_statmount(const long ret, size_t *seq_size) #define STATMOUNT_STRING_REQ (STATMOUNT_MNT_ROOT | STATMOUNT_MNT_POINT | \ STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS | \ STATMOUNT_FS_SUBTYPE | STATMOUNT_SB_SOURCE | \ - STATMOUNT_OPT_ARRAY | STATMOUNT_OPT_SEC_ARRAY) + STATMOUNT_OPT_ARRAY | STATMOUNT_OPT_SEC_ARRAY | \ + STATMOUNT_MNT_UIDMAP | STATMOUNT_MNT_GIDMAP) static int prepare_kstatmount(struct kstatmount *ks, struct mnt_id_req *kreq, struct statmount __user *buf, size_t bufsize, diff --git a/include/linux/mnt_idmapping.h b/include/linux/mnt_idmapping.h index b1b219bc34224..e71a6070a8f8c 100644 --- a/include/linux/mnt_idmapping.h +++ b/include/linux/mnt_idmapping.h @@ -25,6 +25,11 @@ 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)); +static inline bool is_valid_mnt_idmap(const struct mnt_idmap *idmap) +{ + return idmap != &nop_mnt_idmap && idmap != &invalid_mnt_idmap; +} + #ifdef CONFIG_MULTIUSER static inline uid_t __vfsuid_val(vfsuid_t uid) { diff --git a/include/linux/uidgid.h b/include/linux/uidgid.h index f85ec5613721f..2dc767e08f544 100644 --- a/include/linux/uidgid.h +++ b/include/linux/uidgid.h @@ -132,6 +132,7 @@ static inline bool kgid_has_mapping(struct user_namespace *ns, kgid_t gid) u32 map_id_down(struct uid_gid_map *map, u32 id); u32 map_id_up(struct uid_gid_map *map, u32 id); +u32 map_id_range_up(struct uid_gid_map *map, u32 id, u32 count); #else @@ -186,6 +187,11 @@ static inline u32 map_id_down(struct uid_gid_map *map, u32 id) return id; } +static inline u32 map_id_range_up(struct uid_gid_map *map, u32 id, u32 count) +{ + return id; +} + static inline u32 map_id_up(struct uid_gid_map *map, u32 id) { return id; diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h index c07008816acae..0be6ac4c16243 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -179,7 +179,11 @@ struct statmount { __u32 opt_array; /* [str] Array of nul terminated fs options */ __u32 opt_sec_num; /* Number of security options */ __u32 opt_sec_array; /* [str] Array of nul terminated security options */ - __u64 __spare2[46]; + __u32 mnt_uidmap_num; /* Number of uid mappings */ + __u32 mnt_uidmap; /* [str] Array of uid mappings (as seen from callers namespace) */ + __u32 mnt_gidmap_num; /* Number of gid mappings */ + __u32 mnt_gidmap; /* [str] Array of gid mappings (as seen from callers namespace) */ + __u64 __spare2[44]; char str[]; /* Variable size part containing strings */ }; @@ -217,6 +221,8 @@ struct mnt_id_req { #define STATMOUNT_SB_SOURCE 0x00000200U /* Want/got sb_source */ #define STATMOUNT_OPT_ARRAY 0x00000400U /* Want/got opt_... */ #define STATMOUNT_OPT_SEC_ARRAY 0x00000800U /* Want/got opt_sec... */ +#define STATMOUNT_MNT_UIDMAP 0x00001000U /* Want/got uidmap... */ +#define STATMOUNT_MNT_GIDMAP 0x00002000U /* Want/got gidmap... */ /* * Special @mnt_id values that can be passed to listmount diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index aa0b2e47f2f21..682f40d5632d4 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -238,7 +238,7 @@ EXPORT_SYMBOL(__put_user_ns); struct idmap_key { bool map_up; /* true -> id from kid; false -> kid from id */ u32 id; /* id to find */ - u32 count; /* == 0 unless used with map_id_range_down() */ + u32 count; }; /* @@ -343,16 +343,19 @@ u32 map_id_down(struct uid_gid_map *map, u32 id) * UID_GID_MAP_MAX_BASE_EXTENTS. */ static struct uid_gid_extent * -map_id_up_base(unsigned extents, struct uid_gid_map *map, u32 id) +map_id_range_up_base(unsigned extents, struct uid_gid_map *map, u32 id, u32 count) { unsigned idx; - u32 first, last; + u32 first, last, id2; + + id2 = id + count - 1; /* Find the matching extent */ for (idx = 0; idx < extents; idx++) { first = map->extent[idx].lower_first; last = first + map->extent[idx].count - 1; - if (id >= first && id <= last) + if (id >= first && id <= last && + (id2 >= first && id2 <= last)) return &map->extent[idx]; } return NULL; @@ -363,28 +366,28 @@ map_id_up_base(unsigned extents, struct uid_gid_map *map, u32 id) * Can only be called if number of mappings exceeds UID_GID_MAP_MAX_BASE_EXTENTS. */ static struct uid_gid_extent * -map_id_up_max(unsigned extents, struct uid_gid_map *map, u32 id) +map_id_range_up_max(unsigned extents, struct uid_gid_map *map, u32 id, u32 count) { struct idmap_key key; key.map_up = true; - key.count = 1; + key.count = count; key.id = id; return bsearch(&key, map->reverse, extents, sizeof(struct uid_gid_extent), cmp_map_id); } -u32 map_id_up(struct uid_gid_map *map, u32 id) +u32 map_id_range_up(struct uid_gid_map *map, u32 id, u32 count) { struct uid_gid_extent *extent; unsigned extents = map->nr_extents; smp_rmb(); if (extents <= UID_GID_MAP_MAX_BASE_EXTENTS) - extent = map_id_up_base(extents, map, id); + extent = map_id_range_up_base(extents, map, id, count); else - extent = map_id_up_max(extents, map, id); + extent = map_id_range_up_max(extents, map, id, count); /* Map the id or note failure */ if (extent) @@ -395,6 +398,11 @@ u32 map_id_up(struct uid_gid_map *map, u32 id) return id; } +u32 map_id_up(struct uid_gid_map *map, u32 id) +{ + return map_id_range_up(map, id, 1); +} + /** * make_kuid - Map a user-namespace uid pair into a kuid. * @ns: User namespace that the uid is in diff --git a/samples/vfs/samples-vfs.h b/samples/vfs/samples-vfs.h index 103e1e7c4cec2..498baf581b563 100644 --- a/samples/vfs/samples-vfs.h +++ b/samples/vfs/samples-vfs.h @@ -42,7 +42,11 @@ struct statmount { __u32 opt_array; /* [str] Array of nul terminated fs options */ __u32 opt_sec_num; /* Number of security options */ __u32 opt_sec_array; /* [str] Array of nul terminated security options */ - __u64 __spare2[46]; + __u32 mnt_uidmap_num; /* Number of uid mappings */ + __u32 mnt_uidmap; /* [str] Array of uid mappings */ + __u32 mnt_gidmap_num; /* Number of gid mappings */ + __u32 mnt_gidmap; /* [str] Array of gid mappings */ + __u64 __spare2[44]; char str[]; /* Variable size part containing strings */ }; @@ -158,6 +162,14 @@ struct mnt_ns_info { #define STATX_MNT_ID_UNIQUE 0x00004000U /* Want/got extended stx_mount_id */ #endif +#ifndef STATMOUNT_MNT_UIDMAP +#define STATMOUNT_MNT_UIDMAP 0x00002000U /* Want/got uidmap... */ +#endif + +#ifndef STATMOUNT_MNT_GIDMAP +#define STATMOUNT_MNT_GIDMAP 0x00004000U /* Want/got gidmap... */ +#endif + #ifndef MOUNT_ATTR_RDONLY #define MOUNT_ATTR_RDONLY 0x00000001 /* Mount read-only */ #endif diff --git a/samples/vfs/test-list-all-mounts.c b/samples/vfs/test-list-all-mounts.c index 1a02ea4593e39..bb3b83d8f1d7c 100644 --- a/samples/vfs/test-list-all-mounts.c +++ b/samples/vfs/test-list-all-mounts.c @@ -128,20 +128,43 @@ int main(int argc, char *argv[]) STATMOUNT_MNT_POINT | STATMOUNT_MNT_NS_ID | STATMOUNT_MNT_OPTS | - STATMOUNT_FS_TYPE, 0); + STATMOUNT_FS_TYPE | + STATMOUNT_MNT_UIDMAP | + STATMOUNT_MNT_GIDMAP, 0); if (!stmnt) { printf("Failed to statmount(%" PRIu64 ") in mount namespace(%" PRIu64 ")\n", (uint64_t)last_mnt_id, (uint64_t)info.mnt_ns_id); continue; } - printf("mnt_id:\t\t%" PRIu64 "\nmnt_parent_id:\t%" PRIu64 "\nfs_type:\t%s\nmnt_root:\t%s\nmnt_point:\t%s\nmnt_opts:\t%s\n\n", + printf("mnt_id:\t\t%" PRIu64 "\nmnt_parent_id:\t%" PRIu64 "\nfs_type:\t%s\nmnt_root:\t%s\nmnt_point:\t%s\nmnt_opts:\t%s\n", (uint64_t)stmnt->mnt_id, (uint64_t)stmnt->mnt_parent_id, - stmnt->str + stmnt->fs_type, - stmnt->str + stmnt->mnt_root, - stmnt->str + stmnt->mnt_point, - stmnt->str + stmnt->mnt_opts); + (stmnt->mask & STATMOUNT_FS_TYPE) ? stmnt->str + stmnt->fs_type : "", + (stmnt->mask & STATMOUNT_MNT_ROOT) ? stmnt->str + stmnt->mnt_root : "", + (stmnt->mask & STATMOUNT_MNT_POINT) ? stmnt->str + stmnt->mnt_point : "", + (stmnt->mask & STATMOUNT_MNT_OPTS) ? stmnt->str + stmnt->mnt_opts : ""); + + if (stmnt->mask & STATMOUNT_MNT_UIDMAP) { + const char *idmap = stmnt->str + stmnt->mnt_uidmap; + + for (size_t idx = 0; idx < stmnt->mnt_uidmap_num; idx++) { + printf("mnt_uidmap[%lu]:\t%s\n", idx, idmap); + idmap += strlen(idmap) + 1; + } + } + + if (stmnt->mask & STATMOUNT_MNT_GIDMAP) { + const char *idmap = stmnt->str + stmnt->mnt_gidmap; + + for (size_t idx = 0; idx < stmnt->mnt_gidmap_num; idx++) { + printf("mnt_gidmap[%lu]:\t%s\n", idx, idmap); + idmap += strlen(idmap) + 1; + } + } + + printf("\n"); + free(stmnt); } }