From e65ce2a50cf6af216bea6fd80d771fcbb4c0aaa1 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:27 +0100 Subject: acl: handle idmapped mounts The posix acl permission checking helpers determine whether a caller is privileged over an inode according to the acls associated with the inode. Add helpers that make it possible to handle acls on idmapped mounts. The vfs and the filesystems targeted by this first iteration make use of posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to translate basic posix access and default permissions such as the ACL_USER and ACL_GROUP type according to the initial user namespace (or the superblock's user namespace) to and from the caller's current user namespace. Adapt these two helpers to handle idmapped mounts whereby we either map from or into the mount's user namespace depending on in which direction we're translating. Similarly, cap_convert_nscap() is used by the vfs to translate user namespace and non-user namespace aware filesystem capabilities from the superblock's user namespace to the caller's user namespace. Enable it to handle idmapped mounts by accounting for the mount's user namespace. In addition the fileystems targeted in the first iteration of this patch series make use of the posix_acl_chmod() and, posix_acl_update_mode() helpers. Both helpers perform permission checks on the target inode. Let them handle idmapped mounts. These two helpers are called when posix acls are set by the respective filesystems to handle this case we extend the ->set() method to take an additional user namespace argument to pass the mount's user namespace down. Link: https://lore.kernel.org/r/20210121131959.646623-9-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/f2fs/acl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/f2fs/acl.c') diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c index 1e5e9b1136ee..6a95bf28f602 100644 --- a/fs/f2fs/acl.c +++ b/fs/f2fs/acl.c @@ -213,7 +213,8 @@ static int __f2fs_set_acl(struct inode *inode, int type, case ACL_TYPE_ACCESS: name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS; if (acl && !ipage) { - error = posix_acl_update_mode(inode, &mode, &acl); + error = posix_acl_update_mode(&init_user_ns, inode, + &mode, &acl); if (error) return error; set_acl_inode(inode, mode); -- cgit v1.2.3 From 549c7297717c32ee53f156cd949e055e601f67bb Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 21 Jan 2021 14:19:43 +0100 Subject: fs: make helpers idmap mount aware Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig Cc: David Howells Cc: Al Viro Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/f2fs/acl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/f2fs/acl.c') diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c index 6a95bf28f602..a19e86c9adac 100644 --- a/fs/f2fs/acl.c +++ b/fs/f2fs/acl.c @@ -249,7 +249,8 @@ static int __f2fs_set_acl(struct inode *inode, int type, return error; } -int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type) +int f2fs_set_acl(struct user_namespace *mnt_userns, struct inode *inode, + struct posix_acl *acl, int type) { if (unlikely(f2fs_cp_error(F2FS_I_SB(inode)))) return -EIO; -- cgit v1.2.3 From 17232e830afb800acdcc22ae8980bf9d330393ef Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Fri, 25 Dec 2020 16:52:27 +0800 Subject: f2fs: enhance to update i_mode and acl atomically in f2fs_setattr() Previously, in f2fs_setattr(), we don't update S_ISUID|S_ISGID|S_ISVTX bits with S_IRWXUGO bits and acl entries atomically, so in error path, chmod() may partially success, this patch enhances to make chmod() flow being atomical. Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/acl.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'fs/f2fs/acl.c') diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c index 1e5e9b1136ee..732ec10e7890 100644 --- a/fs/f2fs/acl.c +++ b/fs/f2fs/acl.c @@ -200,6 +200,27 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type) return __f2fs_get_acl(inode, type, NULL); } +static int f2fs_acl_update_mode(struct inode *inode, umode_t *mode_p, + struct posix_acl **acl) +{ + umode_t mode = inode->i_mode; + int error; + + if (is_inode_flag_set(inode, FI_ACL_MODE)) + mode = F2FS_I(inode)->i_acl_mode; + + error = posix_acl_equiv_mode(*acl, &mode); + if (error < 0) + return error; + if (error == 0) + *acl = NULL; + if (!in_group_p(inode->i_gid) && + !capable_wrt_inode_uidgid(inode, CAP_FSETID)) + mode &= ~S_ISGID; + *mode_p = mode; + return 0; +} + static int __f2fs_set_acl(struct inode *inode, int type, struct posix_acl *acl, struct page *ipage) { @@ -213,7 +234,7 @@ static int __f2fs_set_acl(struct inode *inode, int type, case ACL_TYPE_ACCESS: name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS; if (acl && !ipage) { - error = posix_acl_update_mode(inode, &mode, &acl); + error = f2fs_acl_update_mode(inode, &mode, &acl); if (error) return error; set_acl_inode(inode, mode); -- cgit v1.2.3