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Diffstat (limited to 'fs/xattr_acl.c')
-rw-r--r--fs/xattr_acl.c96
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;
}