From aa4bf44dc851c6bdd4f7b61b5f2c56c84dfe2ff0 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Wed, 25 Oct 2017 00:04:40 +0200 Subject: userns: use union in {g,u}idmap struct - Add a struct containing two pointer to extents and wrap both the static extent array and the struct into a union. This is done in preparation for bumping the {g,u}idmap limits for user namespaces. - Add brackets around anonymous union when using designated initializers to initialize members in order to please gcc <= 4.4. Signed-off-by: Christian Brauner Signed-off-by: Eric W. Biederman --- include/linux/user_namespace.h | 18 +++++++++++++----- kernel/user.c | 30 ++++++++++++++++++------------ 2 files changed, 31 insertions(+), 17 deletions(-) diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index c18e01252346..7c83d7f6289b 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -12,13 +12,21 @@ #define UID_GID_MAP_MAX_EXTENTS 5 +struct uid_gid_extent { + u32 first; + u32 lower_first; + u32 count; +}; + struct uid_gid_map { /* 64 bytes -- 1 cache line */ u32 nr_extents; - struct uid_gid_extent { - u32 first; - u32 lower_first; - u32 count; - } extent[UID_GID_MAP_MAX_EXTENTS]; + union { + struct uid_gid_extent extent[UID_GID_MAP_MAX_EXTENTS]; + struct { + struct uid_gid_extent *forward; + struct uid_gid_extent *reverse; + }; + }; }; #define USERNS_SETGROUPS_ALLOWED 1UL diff --git a/kernel/user.c b/kernel/user.c index 00281add65b2..9a20acce460d 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -26,26 +26,32 @@ struct user_namespace init_user_ns = { .uid_map = { .nr_extents = 1, - .extent[0] = { - .first = 0, - .lower_first = 0, - .count = 4294967295U, + { + .extent[0] = { + .first = 0, + .lower_first = 0, + .count = 4294967295U, + }, }, }, .gid_map = { .nr_extents = 1, - .extent[0] = { - .first = 0, - .lower_first = 0, - .count = 4294967295U, + { + .extent[0] = { + .first = 0, + .lower_first = 0, + .count = 4294967295U, + }, }, }, .projid_map = { .nr_extents = 1, - .extent[0] = { - .first = 0, - .lower_first = 0, - .count = 4294967295U, + { + .extent[0] = { + .first = 0, + .lower_first = 0, + .count = 4294967295U, + }, }, }, .count = ATOMIC_INIT(3), -- cgit