From ad8f8965ff3448c1d07c3fa82bf99417f9275237 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Wed, 4 Jan 2023 12:59:59 -0800 Subject: [PATCH] Revert "fs: account for filesystem mappings" This reverts commit 791d1985745ee8ab8636f6000c73662b84df6517. --- include/linux/fs.h | 4 +- include/linux/mnt_idmapping.h | 193 +--------------------------------- 2 files changed, 6 insertions(+), 191 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index c7856816df45..cd05fb161d87 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1638,7 +1638,7 @@ static inline void i_gid_write(struct inode *inode, gid_t gid) static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, const struct inode *inode) { - return mapped_kuid_fs(mnt_userns, &init_user_ns, inode->i_uid); + return kuid_into_mnt(mnt_userns, inode->i_uid); } /** @@ -1652,7 +1652,7 @@ static inline kuid_t i_uid_into_mnt(struct user_namespace *mnt_userns, static inline kgid_t i_gid_into_mnt(struct user_namespace *mnt_userns, const struct inode *inode) { - return mapped_kgid_fs(mnt_userns, &init_user_ns, inode->i_gid); + return kgid_into_mnt(mnt_userns, inode->i_gid); } /** diff --git a/include/linux/mnt_idmapping.h b/include/linux/mnt_idmapping.h index 60341cd33ccc..47c7811fadfe 100644 --- a/include/linux/mnt_idmapping.h +++ b/include/linux/mnt_idmapping.h @@ -6,11 +6,6 @@ #include struct user_namespace; -/* - * Carries the initial idmapping of 0:0:4294967295 which is an identity - * mapping. This means that {g,u}id 0 is mapped to {g,u}id 0, {g,u}id 1 is - * mapped to {g,u}id 1, [...], {g,u}id 1000 to {g,u}id 1000, [...]. - */ extern struct user_namespace init_user_ns; /** @@ -69,189 +64,9 @@ static inline kgid_t kgid_from_mnt(struct user_namespace *mnt_userns, return KGIDT_INIT(from_kgid(mnt_userns, kgid)); } -/** - * initial_idmapping - check whether this is the initial mapping - * @ns: idmapping to check - * - * Check whether this is the initial mapping, mapping 0 to 0, 1 to 1, - * [...], 1000 to 1000 [...]. - * - * Return: true if this is the initial mapping, false if not. - */ -static inline bool initial_idmapping(const struct user_namespace *ns) -{ - return ns == &init_user_ns; -} - -/** - * no_idmapping - check whether we can skip remapping a kuid/gid - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping - * - * This function can be used to check whether a remapping between two - * idmappings is required. - * An idmapped mount is a mount that has an idmapping attached to it that - * is different from the filsystem's idmapping and the initial idmapping. - * If the initial mapping is used or the idmapping of the mount and the - * filesystem are identical no remapping is required. - * - * Return: true if remapping can be skipped, false if not. - */ -static inline bool no_idmapping(const struct user_namespace *mnt_userns, - const struct user_namespace *fs_userns) -{ - return initial_idmapping(mnt_userns) || mnt_userns == fs_userns; -} - -/** - * mapped_kuid_fs - 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 - * - * Take a @kuid and remap it from @fs_userns into @mnt_userns. Use this - * function when preparing a @kuid to be reported to userspace. - * - * If no_idmapping() determines that this is not an idmapped mount we can - * simply return @kuid unchanged. - * If initial_idmapping() tells us that the filesystem is not mounted with an - * idmapping we know the value of @kuid won't change when calling - * from_kuid() so we can simply retrieve the value via __kuid_val() - * directly. - * - * Return: @kuid mapped according to @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) -{ - uid_t uid; - - if (no_idmapping(mnt_userns, fs_userns)) - return 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); -} - -/** - * mapped_kgid_fs - 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 - * - * Take a @kgid and remap it from @fs_userns into @mnt_userns. Use this - * function when preparing a @kgid to be reported to userspace. - * - * If no_idmapping() determines that this is not an idmapped mount we can - * simply return @kgid unchanged. - * If initial_idmapping() tells us that the filesystem is not mounted with an - * idmapping we know the value of @kgid won't change when calling - * from_kgid() so we can simply retrieve the value via __kgid_val() - * directly. - * - * Return: @kgid mapped according to @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) -{ - gid_t gid; - - if (no_idmapping(mnt_userns, fs_userns)) - return 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); -} - -/** - * mapped_kuid_user - map a user kuid into a mnt_userns - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping - * @kuid : kuid to be mapped - * - * Use the idmapping of @mnt_userns to remap a @kuid into @fs_userns. Use this - * function when preparing a @kuid to be written to disk or inode. - * - * If no_idmapping() determines that this is not an idmapped mount we can - * simply return @kuid unchanged. - * If initial_idmapping() tells us that the filesystem is not mounted with an - * idmapping we know the value of @kuid won't change when calling - * make_kuid() so we can simply retrieve the value via KUIDT_INIT() - * directly. - * - * Return: @kuid mapped according to @mnt_userns. - * If @kuid has no mapping in either @mnt_userns or @fs_userns INVALID_UID is - * returned. - */ -static inline kuid_t mapped_kuid_user(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; - uid = from_kuid(mnt_userns, kuid); - if (uid == (uid_t)-1) - return INVALID_UID; - if (initial_idmapping(fs_userns)) - return KUIDT_INIT(uid); - return make_kuid(fs_userns, uid); -} - -/** - * mapped_kgid_user - map a user kgid into a mnt_userns - * @mnt_userns: the mount's idmapping - * @fs_userns: the filesystem's idmapping - * @kgid : kgid to be mapped - * - * Use the idmapping of @mnt_userns to remap a @kgid into @fs_userns. Use this - * function when preparing a @kgid to be written to disk or inode. - * - * If no_idmapping() determines that this is not an idmapped mount we can - * simply return @kgid unchanged. - * If initial_idmapping() tells us that the filesystem is not mounted with an - * idmapping we know the value of @kgid won't change when calling - * make_kgid() so we can simply retrieve the value via KGIDT_INIT() - * directly. - * - * Return: @kgid mapped according to @mnt_userns. - * If @kgid has no mapping in either @mnt_userns or @fs_userns INVALID_GID is - * returned. - */ -static inline kgid_t mapped_kgid_user(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; - 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); -} - /** * mapped_fsuid - return caller's fsuid mapped up into a mnt_userns - * @mnt_userns: the mount's idmapping + * @mnt_userns: user namespace of the relevant mount * * Use this helper to initialize a new vfs or filesystem object based on * the caller's fsuid. A common example is initializing the i_uid field of @@ -263,12 +78,12 @@ static inline kgid_t mapped_kgid_user(struct user_namespace *mnt_userns, */ static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) { - return mapped_kuid_user(mnt_userns, &init_user_ns, current_fsuid()); + return kuid_from_mnt(mnt_userns, current_fsuid()); } /** * mapped_fsgid - return caller's fsgid mapped up into a mnt_userns - * @mnt_userns: the mount's idmapping + * @mnt_userns: user namespace of the relevant mount * * Use this helper to initialize a new vfs or filesystem object based on * the caller's fsgid. A common example is initializing the i_gid field of @@ -280,7 +95,7 @@ static inline kuid_t mapped_fsuid(struct user_namespace *mnt_userns) */ static inline kgid_t mapped_fsgid(struct user_namespace *mnt_userns) { - return mapped_kgid_user(mnt_userns, &init_user_ns, current_fsgid()); + return kgid_from_mnt(mnt_userns, current_fsgid()); } #endif /* _LINUX_MNT_IDMAPPING_H */