diff options
Diffstat (limited to 'fs/xattr_acl.c')
| -rw-r--r-- | fs/xattr_acl.c | 96 |
1 files changed, 89 insertions, 7 deletions
diff --git a/fs/xattr_acl.c b/fs/xattr_acl.c index 69d06b07b16..9fbea87fdb6 100644 --- a/fs/xattr_acl.c +++ b/fs/xattr_acl.c @@ -9,13 +9,72 @@ #include <linux/fs.h> #include <linux/posix_acl_xattr.h> #include <linux/gfp.h> +#include <linux/user_namespace.h> +/* + * Fix up the uids and gids in posix acl extended attributes in place. + */ +static void posix_acl_fix_xattr_userns( + struct user_namespace *to, struct user_namespace *from, + void *value, size_t size) +{ + posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; + posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; + int count; + kuid_t uid; + kgid_t gid; + + if (!value) + return; + if (size < sizeof(posix_acl_xattr_header)) + return; + if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) + return; + + count = posix_acl_xattr_count(size); + if (count < 0) + return; + if (count == 0) + return; + + for (end = entry + count; entry != end; entry++) { + switch(le16_to_cpu(entry->e_tag)) { + case ACL_USER: + uid = make_kuid(from, le32_to_cpu(entry->e_id)); + entry->e_id = cpu_to_le32(from_kuid(to, uid)); + break; + case ACL_GROUP: + gid = make_kgid(from, le32_to_cpu(entry->e_id)); + entry->e_id = cpu_to_le32(from_kgid(to, gid)); + break; + default: + break; + } + } +} + +void posix_acl_fix_xattr_from_user(void *value, size_t size) +{ + struct user_namespace *user_ns = current_user_ns(); + if (user_ns == &init_user_ns) + return; + posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); +} + +void posix_acl_fix_xattr_to_user(void *value, size_t size) +{ + struct user_namespace *user_ns = current_user_ns(); + if (user_ns == &init_user_ns) + return; + posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); +} /* * Convert from extended attribute to in-memory representation. */ struct posix_acl * -posix_acl_from_xattr(const void *value, size_t size) +posix_acl_from_xattr(struct user_namespace *user_ns, + const void *value, size_t size) { posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; @@ -50,12 +109,21 @@ posix_acl_from_xattr(const void *value, size_t size) case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: - acl_e->e_id = ACL_UNDEFINED_ID; break; case ACL_USER: + acl_e->e_uid = + make_kuid(user_ns, + le32_to_cpu(entry->e_id)); + if (!uid_valid(acl_e->e_uid)) + goto fail; + break; case ACL_GROUP: - acl_e->e_id = le32_to_cpu(entry->e_id); + acl_e->e_gid = + make_kgid(user_ns, + le32_to_cpu(entry->e_id)); + if (!gid_valid(acl_e->e_gid)) + goto fail; break; default: @@ -74,7 +142,8 @@ EXPORT_SYMBOL (posix_acl_from_xattr); * Convert from in-memory to extended attribute representation. */ int -posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size) +posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, + void *buffer, size_t size) { posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer; posix_acl_xattr_entry *ext_entry = ext_acl->a_entries; @@ -89,9 +158,22 @@ posix_acl_to_xattr(const struct posix_acl *acl, void *buffer, size_t size) ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); for (n=0; n < acl->a_count; n++, ext_entry++) { - ext_entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag); - ext_entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm); - ext_entry->e_id = cpu_to_le32(acl->a_entries[n].e_id); + const struct posix_acl_entry *acl_e = &acl->a_entries[n]; + ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); + ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); + switch(acl_e->e_tag) { + case ACL_USER: + ext_entry->e_id = + cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); + break; + case ACL_GROUP: + ext_entry->e_id = + cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); + break; + default: + ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); + break; + } } return real_size; } |