From: Dave Chinner dchinner@redhat.com

commit 5b55cbc2d72632e874e50d2e36bce608e55aaaea upstream.

[backport for 5.10.y, prior to perag refactoring in v5.14]

Not fatal, the assert is there to catch developer attention. I'm seeing this occasionally during recoveryloop testing after a shutdown, and I don't want this to stop an overnight recoveryloop run as it is currently doing.

Convert the ASSERT to a XFS_IS_CORRUPT() check so it will dump a corruption report into the log and cause a test failure that way, but it won't stop the machine dead.

Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Dave Chinner david@fromorbit.com Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/xfs/xfs_mount.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c index a2a5a0fd9233..402cf828cc91 100644 --- a/fs/xfs/xfs_mount.c +++ b/fs/xfs/xfs_mount.c @@ -126,7 +126,6 @@ __xfs_free_perag( { struct xfs_perag *pag = container_of(head, struct xfs_perag, rcu_head);

- ASSERT(atomic_read(&pag->pag_ref) == 0); kmem_free(pag); }

@@ -145,7 +144,7 @@ xfs_free_perag( pag = radix_tree_delete(&mp->m_perag_tree, agno); spin_unlock(&mp->m_perag_lock); ASSERT(pag); - ASSERT(atomic_read(&pag->pag_ref) == 0); + XFS_IS_CORRUPT(pag->pag_mount, atomic_read(&pag->pag_ref) != 0); xfs_iunlink_destroy(pag); xfs_buf_hash_destroy(pag); call_rcu(&pag->rcu_head, __xfs_free_perag);

From: "Darrick J. Wong" djwong@kernel.org

commit a54f78def73d847cb060b18c4e4a3d1d26c9ca6d upstream.

The recent patch to improve btree cycle checking caused a regression when I rebased the in-memory btree branch atop the 5.19 for-next branch, because in-memory short-pointer btrees do not have AG numbers. This produced the following complaint from kmemleak:

unreferenced object 0xffff88803d47dde8 (size 264): comm "xfs_io", pid 4889, jiffies 4294906764 (age 24.072s) hex dump (first 32 bytes): 90 4d 0b 0f 80 88 ff ff 00 a0 bd 05 80 88 ff ff .M.............. e0 44 3a a0 ff ff ff ff 00 df 08 06 80 88 ff ff .D:............. backtrace: [<ffffffffa0388059>] xfbtree_dup_cursor+0x49/0xc0 [xfs] [<ffffffffa029887b>] xfs_btree_dup_cursor+0x3b/0x200 [xfs] [<ffffffffa029af5d>] __xfs_btree_split+0x6ad/0x820 [xfs] [<ffffffffa029b130>] xfs_btree_split+0x60/0x110 [xfs] [<ffffffffa029f6da>] xfs_btree_make_block_unfull+0x19a/0x1f0 [xfs] [<ffffffffa029fada>] xfs_btree_insrec+0x3aa/0x810 [xfs] [<ffffffffa029fff3>] xfs_btree_insert+0xb3/0x240 [xfs] [<ffffffffa02cb729>] xfs_rmap_insert+0x99/0x200 [xfs] [<ffffffffa02cf142>] xfs_rmap_map_shared+0x192/0x5f0 [xfs] [<ffffffffa02cf60b>] xfs_rmap_map_raw+0x6b/0x90 [xfs] [<ffffffffa0384a85>] xrep_rmap_stash+0xd5/0x1d0 [xfs] [<ffffffffa0384dc0>] xrep_rmap_visit_bmbt+0xa0/0xf0 [xfs] [<ffffffffa0384fb6>] xrep_rmap_scan_iext+0x56/0xa0 [xfs] [<ffffffffa03850d8>] xrep_rmap_scan_ifork+0xd8/0x160 [xfs] [<ffffffffa0385195>] xrep_rmap_scan_inode+0x35/0x80 [xfs] [<ffffffffa03852ee>] xrep_rmap_find_rmaps+0x10e/0x270 [xfs]

I noticed that xfs_btree_insrec has a bunch of debug code that return out of the function immediately, without freeing the "new" btree cursor that can be returned when _make_block_unfull calls xfs_btree_split. Fix the error return in this function to free the btree cursor.

Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Dave Chinner dchinner@redhat.com Signed-off-by: Dave Chinner david@fromorbit.com Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/xfs/libxfs/xfs_btree.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c index 24c7d30e41df..0926363179a7 100644 --- a/fs/xfs/libxfs/xfs_btree.c +++ b/fs/xfs/libxfs/xfs_btree.c @@ -3190,7 +3190,7 @@ xfs_btree_insrec( struct xfs_btree_block *block; /* btree block */ struct xfs_buf *bp; /* buffer for block */ union xfs_btree_ptr nptr; /* new block ptr */ - struct xfs_btree_cur *ncur; /* new btree cursor */ + struct xfs_btree_cur *ncur = NULL; /* new btree cursor */ union xfs_btree_key nkey; /* new block key */ union xfs_btree_key *lkey; int optr; /* old key/record index */ @@ -3270,7 +3270,7 @@ xfs_btree_insrec( #ifdef DEBUG error = xfs_btree_check_block(cur, block, level, bp); if (error) - return error; + goto error0; #endif

/* @@ -3290,7 +3290,7 @@ xfs_btree_insrec( for (i = numrecs - ptr; i >= 0; i--) { error = xfs_btree_debug_check_ptr(cur, pp, i, level); if (error) - return error; + goto error0; }

xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1); @@ -3375,6 +3375,8 @@ xfs_btree_insrec( return 0;

error0: + if (ncur) + xfs_btree_del_cursor(ncur, error); return error; }

From: Dave Chinner dchinner@redhat.com

commit fbe7e520036583a783b13ff9744e35c2a329d9a4 upstream.

In XFS, we always update the inode change and modification time when any fallocate() operation succeeds. Furthermore, as various fallocate modes can change the file contents (extending EOF, punching holes, zeroing things, shifting extents), we should drop file privileges like suid just like we do for a regular write(). There's already a VFS helper that figures all this out for us, so use that.

The net effect of this is that we no longer drop suid/sgid if the caller is root, but we also now drop file capabilities.

We also move the xfs_update_prealloc_flags() function so that it now is only called by the scope that needs to set the the prealloc flag.

Based on a patch from Darrick Wong.

Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/xfs/xfs_file.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 630525b1da77..a95af57a59a7 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -895,6 +895,10 @@ xfs_file_fallocate( goto out_unlock; }

+ error = file_modified(file); + if (error) + goto out_unlock; + if (mode & FALLOC_FL_PUNCH_HOLE) { error = xfs_free_file_space(ip, offset, len); if (error) @@ -996,11 +1000,12 @@ xfs_file_fallocate( if (error) goto out_unlock; } - }

- error = xfs_update_prealloc_flags(ip, flags); - if (error) - goto out_unlock; + error = xfs_update_prealloc_flags(ip, XFS_PREALLOC_SET); + if (error) + goto out_unlock; + + }

/* Change file size if needed */ if (new_size) {

From: "Darrick J. Wong" djwong@kernel.org

commit e014f37db1a2d109afa750042ac4d69cf3e3d88e upstream.

[remove userns argument of setattr_copy() for 5.10.y backport]

Filipe Manana pointed out that XFS' behavior w.r.t. setuid/setgid revocation isn't consistent with btrfs[1] or ext4. Those two filesystems use the VFS function setattr_copy to convey certain attributes from struct iattr into the VFS inode structure.

Andrey Zhadchenko reported[2] that XFS uses the wrong user namespace to decide if it should clear setgid and setuid on a file attribute update. This is a second symptom of the problem that Filipe noticed.

XFS, on the other hand, open-codes setattr_copy in xfs_setattr_mode, xfs_setattr_nonsize, and xfs_setattr_time. Regrettably, setattr_copy is /not/ a simple copy function; it contains additional logic to clear the setgid bit when setting the mode, and XFS' version no longer matches.

The VFS implements its own setuid/setgid stripping logic, which establishes consistent behavior. It's a tad unfortunate that it's scattered across notify_change, should_remove_suid, and setattr_copy but XFS should really follow the Linux VFS. Adapt XFS to use the VFS functions and get rid of the old functions.

[1] https://lore.kernel.org/fstests/CAL3q7H47iNQ=Wmk83WcGB-KBJVOEtR9+qGczzCeXJ9Y... [2] https://lore.kernel.org/linux-xfs/20220221182218.748084-1-andrey.zhadchenko@...

Fixes: 7fa294c8991c ("userns: Allow chown and setgid preservation") Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Dave Chinner dchinner@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Christian Brauner brauner@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/xfs/xfs_iops.c | 56 +++-------------------------------------------- fs/xfs/xfs_pnfs.c | 3 ++- 2 files changed, 5 insertions(+), 54 deletions(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index 6a3026e78a9b..69fef29df428 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -595,37 +595,6 @@ xfs_vn_getattr( return 0; }

-static void -xfs_setattr_mode( - struct xfs_inode *ip, - struct iattr *iattr) -{ - struct inode *inode = VFS_I(ip); - umode_t mode = iattr->ia_mode; - - ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); - - inode->i_mode &= S_IFMT; - inode->i_mode |= mode & ~S_IFMT; -} - -void -xfs_setattr_time( - struct xfs_inode *ip, - struct iattr *iattr) -{ - struct inode *inode = VFS_I(ip); - - ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); - - if (iattr->ia_valid & ATTR_ATIME) - inode->i_atime = iattr->ia_atime; - if (iattr->ia_valid & ATTR_CTIME) - inode->i_ctime = iattr->ia_ctime; - if (iattr->ia_valid & ATTR_MTIME) - inode->i_mtime = iattr->ia_mtime; -} - static int xfs_vn_change_ok( struct dentry *dentry, @@ -740,16 +709,6 @@ xfs_setattr_nonsize( goto out_cancel; }

- /* - * CAP_FSETID overrides the following restrictions: - * - * The set-user-ID and set-group-ID bits of a file will be - * cleared upon successful return from chown() - */ - if ((inode->i_mode & (S_ISUID|S_ISGID)) && - !capable(CAP_FSETID)) - inode->i_mode &= ~(S_ISUID|S_ISGID); - /* * Change the ownerships and register quota modifications * in the transaction. @@ -761,7 +720,6 @@ xfs_setattr_nonsize( olddquot1 = xfs_qm_vop_chown(tp, ip, &ip->i_udquot, udqp); } - inode->i_uid = uid; } if (!gid_eq(igid, gid)) { if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_GQUOTA_ON(mp)) { @@ -772,15 +730,10 @@ xfs_setattr_nonsize( olddquot2 = xfs_qm_vop_chown(tp, ip, &ip->i_gdquot, gdqp); } - inode->i_gid = gid; } }

- if (mask & ATTR_MODE) - xfs_setattr_mode(ip, iattr); - if (mask & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME)) - xfs_setattr_time(ip, iattr); - + setattr_copy(inode, iattr); xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

XFS_STATS_INC(mp, xs_ig_attrchg); @@ -1025,11 +978,8 @@ xfs_setattr_size( xfs_inode_clear_eofblocks_tag(ip); }

- if (iattr->ia_valid & ATTR_MODE) - xfs_setattr_mode(ip, iattr); - if (iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME)) - xfs_setattr_time(ip, iattr); - + ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID))); + setattr_copy(inode, iattr); xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

XFS_STATS_INC(mp, xs_ig_attrchg); diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c index 64ab54f2fe81..053b99929f83 100644 --- a/fs/xfs/xfs_pnfs.c +++ b/fs/xfs/xfs_pnfs.c @@ -285,7 +285,8 @@ xfs_fs_commit_blocks( xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

- xfs_setattr_time(ip, iattr); + ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID))); + setattr_copy(inode, iattr); if (update_isize) { i_size_write(inode, iattr->ia_size); ip->i_d.di_size = iattr->ia_size;

From: Yang Xu xuyang2018.jy@fujitsu.com

commit 1639a49ccdce58ea248841ed9b23babcce6dbb0b upstream.

[remove userns argument of helpers for 5.10.y backport]

Move setgid handling out of individual filesystems and into the VFS itself to stop the proliferation of setgid inheritance bugs.

Creating files that have both the S_IXGRP and S_ISGID bit raised in directories that themselves have the S_ISGID bit set requires additional privileges to avoid security issues.

When a filesystem creates a new inode it needs to take care that the caller is either in the group of the newly created inode or they have CAP_FSETID in their current user namespace and are privileged over the parent directory of the new inode. If any of these two conditions is true then the S_ISGID bit can be raised for an S_IXGRP file and if not it needs to be stripped.

However, there are several key issues with the current implementation:

* S_ISGID stripping logic is entangled with umask stripping.

If a filesystem doesn't support or enable POSIX ACLs then umask stripping is done directly in the vfs before calling into the filesystem. If the filesystem does support POSIX ACLs then unmask stripping may be done in the filesystem itself when calling posix_acl_create().

Since umask stripping has an effect on S_ISGID inheritance, e.g., by stripping the S_IXGRP bit from the file to be created and all relevant filesystems have to call posix_acl_create() before inode_init_owner() where we currently take care of S_ISGID handling S_ISGID handling is order dependent. IOW, whether or not you get a setgid bit depends on POSIX ACLs and umask and in what order they are called.

Note that technically filesystems are free to impose their own ordering between posix_acl_create() and inode_init_owner() meaning that there's additional ordering issues that influence S_SIGID inheritance.

* Filesystems that don't rely on inode_init_owner() don't get S_ISGID stripping logic.

While that may be intentional (e.g. network filesystems might just defer setgid stripping to a server) it is often just a security issue.

This is not just ugly it's unsustainably messy especially since we do still have bugs in this area years after the initial round of setgid bugfixes.

So the current state is quite messy and while we won't be able to make it completely clean as posix_acl_create() is still a filesystem specific call we can improve the S_SIGD stripping situation quite a bit by hoisting it out of inode_init_owner() and into the vfs creation operations. This means we alleviate the burden for filesystems to handle S_ISGID stripping correctly and can standardize the ordering between S_ISGID and umask stripping in the vfs.

We add a new helper vfs_prepare_mode() so S_ISGID handling is now done in the VFS before umask handling. This has S_ISGID handling is unaffected unaffected by whether umask stripping is done by the VFS itself (if no POSIX ACLs are supported or enabled) or in the filesystem in posix_acl_create() (if POSIX ACLs are supported).

The vfs_prepare_mode() helper is called directly in vfs_*() helpers that create new filesystem objects. We need to move them into there to make sure that filesystems like overlayfs hat have callchains like:

sys_mknod() -> do_mknodat(mode) -> .mknod = ovl_mknod(mode) -> ovl_create(mode) -> vfs_mknod(mode)

get S_ISGID stripping done when calling into lower filesystems via vfs_*() creation helpers. Moving vfs_prepare_mode() into e.g. vfs_mknod() takes care of that. This is in any case semantically cleaner because S_ISGID stripping is VFS security requirement.

Security hooks so far have seen the mode with the umask applied but without S_ISGID handling done. The relevant hooks are called outside of vfs_*() creation helpers so by calling vfs_prepare_mode() from vfs_*() helpers the security hooks would now see the mode without umask stripping applied. For now we fix this by passing the mode with umask settings applied to not risk any regressions for LSM hooks. IOW, nothing changes for LSM hooks. It is worth pointing out that security hooks never saw the mode that is seen by the filesystem when actually creating the file. They have always been completely misplaced for that to work.

The following filesystems use inode_init_owner() and thus relied on S_ISGID stripping: spufs, 9p, bfs, btrfs, ext2, ext4, f2fs, hfsplus, hugetlbfs, jfs, minix, nilfs2, ntfs3, ocfs2, omfs, overlayfs, ramfs, reiserfs, sysv, ubifs, udf, ufs, xfs, zonefs, bpf, tmpfs.

All of the above filesystems end up calling inode_init_owner() when new filesystem objects are created through the ->mkdir(), ->mknod(), ->create(), ->tmpfile(), ->rename() inode operations.

Since directories always inherit the S_ISGID bit with the exception of xfs when irix_sgid_inherit mode is turned on S_ISGID stripping doesn't apply. The ->symlink() and ->link() inode operations trivially inherit the mode from the target and the ->rename() inode operation inherits the mode from the source inode. All other creation inode operations will get S_ISGID handling via vfs_prepare_mode() when called from their relevant vfs_*() helpers.

In addition to this there are filesystems which allow the creation of filesystem objects through ioctl()s or - in the case of spufs - circumventing the vfs in other ways. If filesystem objects are created through ioctl()s the vfs doesn't know about it and can't apply regular permission checking including S_ISGID logic. Therfore, a filesystem relying on S_ISGID stripping in inode_init_owner() in their ioctl() callpath will be affected by moving this logic into the vfs. We audited those filesystems:

* btrfs allows the creation of filesystem objects through various ioctls(). Snapshot creation literally takes a snapshot and so the mode is fully preserved and S_ISGID stripping doesn't apply.

Creating a new subvolum relies on inode_init_owner() in btrfs_new_subvol_inode() but only creates directories and doesn't raise S_ISGID.

* ocfs2 has a peculiar implementation of reflinks. In contrast to e.g. xfs and btrfs FICLONE/FICLONERANGE ioctl() that is only concerned with the actual extents ocfs2 uses a separate ioctl() that also creates the target file.

Iow, ocfs2 circumvents the vfs entirely here and did indeed rely on inode_init_owner() to strip the S_ISGID bit. This is the only place where a filesystem needs to call mode_strip_sgid() directly but this is self-inflicted pain.

* spufs doesn't go through the vfs at all and doesn't use ioctl()s either. Instead it has a dedicated system call spufs_create() which allows the creation of filesystem objects. But spufs only creates directories and doesn't allo S_SIGID bits, i.e. it specifically only allows 0777 bits.

* bpf uses vfs_mkobj() but also doesn't allow S_ISGID bits to be created.

The patch will have an effect on ext2 when the EXT2_MOUNT_GRPID mount option is used, on ext4 when the EXT4_MOUNT_GRPID mount option is used, and on xfs when the XFS_FEAT_GRPID mount option is used. When any of these filesystems are mounted with their respective GRPID option then newly created files inherit the parent directories group unconditionally. In these cases non of the filesystems call inode_init_owner() and thus did never strip the S_ISGID bit for newly created files. Moving this logic into the VFS means that they now get the S_ISGID bit stripped. This is a user visible change. If this leads to regressions we will either need to figure out a better way or we need to revert. However, given the various setgid bugs that we found just in the last two years this is a regression risk we should take.

Associated with this change is a new set of fstests to enforce the semantics for all new filesystems.

Link: https://lore.kernel.org/ceph-devel/20220427092201.wvsdjbnc7b4dttaw@wittgenst... [1] Link: e014f37db1a2 ("xfs: use setattr_copy to set vfs inode attributes") [2] Link: 01ea173e103e ("xfs: fix up non-directory creation in SGID directories") [3] Link: fd84bfdddd16 ("ceph: fix up non-directory creation in SGID directories") [4] Link: https://lore.kernel.org/r/1657779088-2242-3-git-send-email-xuyang2018.jy@fuj... Suggested-by: Dave Chinner david@fromorbit.com Suggested-by: Christian Brauner (Microsoft) brauner@kernel.org Reviewed-by: Darrick J. Wong djwong@kernel.org Reviewed-and-Tested-by: Jeff Layton jlayton@kernel.org Signed-off-by: Yang Xu xuyang2018.jy@fujitsu.com [brauner@kernel.org: rewrote commit message] Signed-off-by: Christian Brauner (Microsoft) brauner@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/inode.c | 2 -- fs/namei.c | 80 ++++++++++++++++++++++++++++++++++++++++-------- fs/ocfs2/namei.c | 1 + 3 files changed, 68 insertions(+), 15 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c index 23d03abcb0ff..52f834b6a3ad 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2147,8 +2147,6 @@ void inode_init_owner(struct inode *inode, const struct inode *dir, /* Directories are special, and always inherit S_ISGID */ if (S_ISDIR(mode)) mode |= S_ISGID; - else - mode = mode_strip_sgid(dir, mode); } else inode->i_gid = current_fsgid(); inode->i_mode = mode; diff --git a/fs/namei.c b/fs/namei.c index 4159c140fa47..3d98db9802a7 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2798,6 +2798,63 @@ void unlock_rename(struct dentry *p1, struct dentry *p2) } EXPORT_SYMBOL(unlock_rename);

+/** + * mode_strip_umask - handle vfs umask stripping + * @dir: parent directory of the new inode + * @mode: mode of the new inode to be created in @dir + * + * Umask stripping depends on whether or not the filesystem supports POSIX + * ACLs. If the filesystem doesn't support it umask stripping is done directly + * in here. If the filesystem does support POSIX ACLs umask stripping is + * deferred until the filesystem calls posix_acl_create(). + * + * Returns: mode + */ +static inline umode_t mode_strip_umask(const struct inode *dir, umode_t mode) +{ + if (!IS_POSIXACL(dir)) + mode &= ~current_umask(); + return mode; +} + +/** + * vfs_prepare_mode - prepare the mode to be used for a new inode + * @dir: parent directory of the new inode + * @mode: mode of the new inode + * @mask_perms: allowed permission by the vfs + * @type: type of file to be created + * + * This helper consolidates and enforces vfs restrictions on the @mode of a new + * object to be created. + * + * Umask stripping depends on whether the filesystem supports POSIX ACLs (see + * the kernel documentation for mode_strip_umask()). Moving umask stripping + * after setgid stripping allows the same ordering for both non-POSIX ACL and + * POSIX ACL supporting filesystems. + * + * Note that it's currently valid for @type to be 0 if a directory is created. + * Filesystems raise that flag individually and we need to check whether each + * filesystem can deal with receiving S_IFDIR from the vfs before we enforce a + * non-zero type. + * + * Returns: mode to be passed to the filesystem + */ +static inline umode_t vfs_prepare_mode(const struct inode *dir, umode_t mode, + umode_t mask_perms, umode_t type) +{ + mode = mode_strip_sgid(dir, mode); + mode = mode_strip_umask(dir, mode); + + /* + * Apply the vfs mandated allowed permission mask and set the type of + * file to be created before we call into the filesystem. + */ + mode &= (mask_perms & ~S_IFMT); + mode |= (type & S_IFMT); + + return mode; +} + int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool want_excl) { @@ -2807,8 +2864,8 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,

if (!dir->i_op->create) return -EACCES; /* shouldn't it be ENOSYS? */ - mode &= S_IALLUGO; - mode |= S_IFREG; + + mode = vfs_prepare_mode(dir, mode, S_IALLUGO, S_IFREG); error = security_inode_create(dir, dentry, mode); if (error) return error; @@ -3072,8 +3129,7 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file, if (open_flag & O_CREAT) { if (open_flag & O_EXCL) open_flag &= ~O_TRUNC; - if (!IS_POSIXACL(dir->d_inode)) - mode &= ~current_umask(); + mode = vfs_prepare_mode(dir->d_inode, mode, mode, mode); if (likely(got_write)) create_error = may_o_create(&nd->path, dentry, mode); else @@ -3286,8 +3342,7 @@ struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode, int open_flag) child = d_alloc(dentry, &slash_name); if (unlikely(!child)) goto out_err; - if (!IS_POSIXACL(dir)) - mode &= ~current_umask(); + mode = vfs_prepare_mode(dir, mode, mode, mode); error = dir->i_op->tmpfile(dir, child, mode); if (error) goto out_err; @@ -3548,6 +3603,7 @@ int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) if (!dir->i_op->mknod) return -EPERM;

+ mode = vfs_prepare_mode(dir, mode, mode, mode); error = devcgroup_inode_mknod(mode, dev); if (error) return error; @@ -3596,9 +3652,8 @@ static long do_mknodat(int dfd, const char __user *filename, umode_t mode, if (IS_ERR(dentry)) return PTR_ERR(dentry);

- if (!IS_POSIXACL(path.dentry->d_inode)) - mode &= ~current_umask(); - error = security_path_mknod(&path, dentry, mode, dev); + error = security_path_mknod(&path, dentry, + mode_strip_umask(path.dentry->d_inode, mode), dev); if (error) goto out; switch (mode & S_IFMT) { @@ -3646,7 +3701,7 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (!dir->i_op->mkdir) return -EPERM;

- mode &= (S_IRWXUGO|S_ISVTX); + mode = vfs_prepare_mode(dir, mode, S_IRWXUGO | S_ISVTX, 0); error = security_inode_mkdir(dir, dentry, mode); if (error) return error; @@ -3673,9 +3728,8 @@ static long do_mkdirat(int dfd, const char __user *pathname, umode_t mode) if (IS_ERR(dentry)) return PTR_ERR(dentry);

- if (!IS_POSIXACL(path.dentry->d_inode)) - mode &= ~current_umask(); - error = security_path_mkdir(&path, dentry, mode); + error = security_path_mkdir(&path, dentry, + mode_strip_umask(path.dentry->d_inode, mode)); if (!error) error = vfs_mkdir(path.dentry->d_inode, dentry, mode); done_path_create(&path, dentry); diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c index 856474b0a1ae..df1f6b7aa797 100644 --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -198,6 +198,7 @@ static struct inode *ocfs2_get_init_inode(struct inode *dir, umode_t mode) * callers. */ if (S_ISDIR(mode)) set_nlink(inode, 2); + mode = mode_strip_sgid(dir, mode); inode_init_owner(inode, dir, mode); status = dquot_initialize(inode); if (status)

commit e243e3f94c804ecca9a8241b5babe28f35258ef4 upstream.

Move the helper from inode.c to attr.c. This keeps the the core of the set{g,u}id stripping logic in one place when we add follow-up changes. It is the better place anyway, since should_remove_suid() returns ATTR_KILL_S{G,U}ID flags.

Reviewed-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Christian Brauner (Microsoft) brauner@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/attr.c | 29 +++++++++++++++++++++++++++++ fs/inode.c | 29 ----------------------------- 2 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c index 300ba5153868..666489157978 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -20,6 +20,35 @@

#include "internal.h"

+/* + * The logic we want is + * + * if suid or (sgid and xgrp) + * remove privs + */ +int should_remove_suid(struct dentry *dentry) +{ + umode_t mode = d_inode(dentry)->i_mode; + int kill = 0; + + /* suid always must be killed */ + if (unlikely(mode & S_ISUID)) + kill = ATTR_KILL_SUID; + + /* + * sgid without any exec bits is just a mandatory locking mark; leave + * it alone. If some exec bits are set, it's a real sgid; kill it. + */ + if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) + kill |= ATTR_KILL_SGID; + + if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) + return kill; + + return 0; +} +EXPORT_SYMBOL(should_remove_suid); + static bool chown_ok(const struct inode *inode, kuid_t uid) { if (uid_eq(current_fsuid(), inode->i_uid) && diff --git a/fs/inode.c b/fs/inode.c index 63f86aeda7fd..f52dd6feea98 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1854,35 +1854,6 @@ void touch_atime(const struct path *path) } EXPORT_SYMBOL(touch_atime);

-/* - * The logic we want is - * - * if suid or (sgid and xgrp) - * remove privs - */ -int should_remove_suid(struct dentry *dentry) -{ - umode_t mode = d_inode(dentry)->i_mode; - int kill = 0; - - /* suid always must be killed */ - if (unlikely(mode & S_ISUID)) - kill = ATTR_KILL_SUID; - - /* - * sgid without any exec bits is just a mandatory locking mark; leave - * it alone. If some exec bits are set, it's a real sgid; kill it. - */ - if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) - kill |= ATTR_KILL_SGID; - - if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) - return kill; - - return 0; -} -EXPORT_SYMBOL(should_remove_suid); - /* * Return mask of changes for notify_change() that need to be done as a * response to write or truncate. Return 0 if nothing has to be changed.

commit ed5a7047d2011cb6b2bf84ceb6680124cc6a7d95 upstream.

[backported to 5.10.y, prior to idmapped mounts]

Currently setgid stripping in file_remove_privs()'s should_remove_suid() helper is inconsistent with other parts of the vfs. Specifically, it only raises ATTR_KILL_SGID if the inode is S_ISGID and S_IXGRP but not if the inode isn't in the caller's groups and the caller isn't privileged over the inode although we require this already in setattr_prepare() and setattr_copy() and so all filesystem implement this requirement implicitly because they have to use setattr_{prepare,copy}() anyway.

But the inconsistency shows up in setgid stripping bugs for overlayfs in xfstests (e.g., generic/673, generic/683, generic/685, generic/686, generic/687). For example, we test whether suid and setgid stripping works correctly when performing various write-like operations as an unprivileged user (fallocate, reflink, write, etc.):

echo "Test 1 - qa_user, non-exec file $verb" setup_testfile chmod a+rws $junk_file commit_and_check "$qa_user" "$verb" 64k 64k

The test basically creates a file with 6666 permissions. While the file has the S_ISUID and S_ISGID bits set it does not have the S_IXGRP set. On a regular filesystem like xfs what will happen is:

sys_fallocate() -> vfs_fallocate() -> xfs_file_fallocate() -> file_modified() -> __file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = ATTR_FORCE | kill; -> notify_change() -> setattr_copy()

In should_remove_suid() we can see that ATTR_KILL_SUID is raised unconditionally because the file in the test has S_ISUID set.

But we also see that ATTR_KILL_SGID won't be set because while the file is S_ISGID it is not S_IXGRP (see above) which is a condition for ATTR_KILL_SGID being raised.

So by the time we call notify_change() we have attr->ia_valid set to ATTR_KILL_SUID | ATTR_FORCE. Now notify_change() sees that ATTR_KILL_SUID is set and does:

ia_valid = attr->ia_valid |= ATTR_MODE attr->ia_mode = (inode->i_mode & ~S_ISUID);

which means that when we call setattr_copy() later we will definitely update inode->i_mode. Note that attr->ia_mode still contains S_ISGID.

Now we call into the filesystem's ->setattr() inode operation which will end up calling setattr_copy(). Since ATTR_MODE is set we will hit:

if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode); if (!vfsgid_in_group_p(vfsgid) && !capable_wrt_inode_uidgid(mnt_userns, inode, CAP_FSETID)) mode &= ~S_ISGID; inode->i_mode = mode; }

and since the caller in the test is neither capable nor in the group of the inode the S_ISGID bit is stripped.

But assume the file isn't suid then ATTR_KILL_SUID won't be raised which has the consequence that neither the setgid nor the suid bits are stripped even though it should be stripped because the inode isn't in the caller's groups and the caller isn't privileged over the inode.

If overlayfs is in the mix things become a bit more complicated and the bug shows up more clearly. When e.g., ovl_setattr() is hit from ovl_fallocate()'s call to file_remove_privs() then ATTR_KILL_SUID and ATTR_KILL_SGID might be raised but because the check in notify_change() is questioning the ATTR_KILL_SGID flag again by requiring S_IXGRP for it to be stripped the S_ISGID bit isn't removed even though it should be stripped:

sys_fallocate() -> vfs_fallocate() -> ovl_fallocate() -> file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = ATTR_FORCE | kill; -> notify_change() -> ovl_setattr() // TAKE ON MOUNTER'S CREDS -> ovl_do_notify_change() -> notify_change() // GIVE UP MOUNTER'S CREDS // TAKE ON MOUNTER'S CREDS -> vfs_fallocate() -> xfs_file_fallocate() -> file_modified() -> __file_remove_privs() -> dentry_needs_remove_privs() -> should_remove_suid() -> __remove_privs() newattrs.ia_valid = attr_force | kill; -> notify_change()

The fix for all of this is to make file_remove_privs()'s should_remove_suid() helper to perform the same checks as we already require in setattr_prepare() and setattr_copy() and have notify_change() not pointlessly requiring S_IXGRP again. It doesn't make any sense in the first place because the caller must calculate the flags via should_remove_suid() anyway which would raise ATTR_KILL_SGID.

While we're at it we move should_remove_suid() from inode.c to attr.c where it belongs with the rest of the iattr helpers. Especially since it returns ATTR_KILL_S{G,U}ID flags. We also rename it to setattr_should_drop_suidgid() to better reflect that it indicates both setuid and setgid bit removal and also that it returns attr flags.

Running xfstests with this doesn't report any regressions. We should really try and use consistent checks.

Reviewed-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Christian Brauner (Microsoft) brauner@kernel.org Signed-off-by: Amir Goldstein amir73il@gmail.com --- Documentation/trace/ftrace.rst | 2 +- fs/attr.c | 31 +++++++++++++++++-------------- fs/inode.c | 2 +- fs/ocfs2/file.c | 4 ++-- fs/open.c | 6 +++--- include/linux/fs.h | 2 +- 6 files changed, 25 insertions(+), 22 deletions(-)

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst index 87cf5c010d5d..ed2e45f9b762 100644 --- a/Documentation/trace/ftrace.rst +++ b/Documentation/trace/ftrace.rst @@ -2923,7 +2923,7 @@ Produces:: bash-1994 [000] .... 4342.324898: ima_get_action <-process_measurement bash-1994 [000] .... 4342.324898: ima_match_policy <-ima_get_action bash-1994 [000] .... 4342.324899: do_truncate <-do_last - bash-1994 [000] .... 4342.324899: should_remove_suid <-do_truncate + bash-1994 [000] .... 4342.324899: setattr_should_drop_suidgid <-do_truncate bash-1994 [000] .... 4342.324899: notify_change <-do_truncate bash-1994 [000] .... 4342.324900: current_fs_time <-notify_change bash-1994 [000] .... 4342.324900: current_kernel_time <-current_fs_time diff --git a/fs/attr.c b/fs/attr.c index c8049ae34a2e..326a0db3296d 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -45,34 +45,37 @@ int setattr_should_drop_sgid(const struct inode *inode) return 0; }

-/* - * The logic we want is +/** + * setattr_should_drop_suidgid - determine whether the set{g,u}id bit needs to + * be dropped + * @inode: inode to check + * + * This function determines whether the set{g,u}id bits need to be removed. + * If the setuid bit needs to be removed ATTR_KILL_SUID is returned. If the + * setgid bit needs to be removed ATTR_KILL_SGID is returned. If both + * set{g,u}id bits need to be removed the corresponding mask of both flags is + * returned. * - * if suid or (sgid and xgrp) - * remove privs + * Return: A mask of ATTR_KILL_S{G,U}ID indicating which - if any - setid bits + * to remove, 0 otherwise. */ -int should_remove_suid(struct dentry *dentry) +int setattr_should_drop_suidgid(struct inode *inode) { - umode_t mode = d_inode(dentry)->i_mode; + umode_t mode = inode->i_mode; int kill = 0;

/* suid always must be killed */ if (unlikely(mode & S_ISUID)) kill = ATTR_KILL_SUID;

- /* - * sgid without any exec bits is just a mandatory locking mark; leave - * it alone. If some exec bits are set, it's a real sgid; kill it. - */ - if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) - kill |= ATTR_KILL_SGID; + kill |= setattr_should_drop_sgid(inode);

if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) return kill;

return 0; } -EXPORT_SYMBOL(should_remove_suid); +EXPORT_SYMBOL(setattr_should_drop_suidgid);

static bool chown_ok(const struct inode *inode, kuid_t uid) { @@ -350,7 +353,7 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de } } if (ia_valid & ATTR_KILL_SGID) { - if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { + if (mode & S_ISGID) { if (!(ia_valid & ATTR_MODE)) { ia_valid = attr->ia_valid |= ATTR_MODE; attr->ia_mode = inode->i_mode; diff --git a/fs/inode.c b/fs/inode.c index f52dd6feea98..7ec90788d8be 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1868,7 +1868,7 @@ int dentry_needs_remove_privs(struct dentry *dentry) if (IS_NOSEC(inode)) return 0;

- mask = should_remove_suid(dentry); + mask = setattr_should_drop_suidgid(inode); ret = security_inode_need_killpriv(dentry); if (ret < 0) return ret; diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 1470b49adb2d..ca00cac5a12f 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -1994,7 +1994,7 @@ static int __ocfs2_change_file_space(struct file *file, struct inode *inode, } }

- if (file && should_remove_suid(file->f_path.dentry)) { + if (file && setattr_should_drop_suidgid(file_inode(file))) { ret = __ocfs2_write_remove_suid(inode, di_bh); if (ret) { mlog_errno(ret); @@ -2282,7 +2282,7 @@ static int ocfs2_prepare_inode_for_write(struct file *file, * inode. There's also the dinode i_size state which * can be lost via setattr during extending writes (we * set inode->i_size at the end of a write. */ - if (should_remove_suid(dentry)) { + if (setattr_should_drop_suidgid(inode)) { if (meta_level == 0) { ocfs2_inode_unlock_for_extent_tree(inode, &di_bh, diff --git a/fs/open.c b/fs/open.c index b3fbb4300fc9..1ca4b236fdbe 100644 --- a/fs/open.c +++ b/fs/open.c @@ -665,10 +665,10 @@ int chown_common(const struct path *path, uid_t user, gid_t group) newattrs.ia_valid |= ATTR_GID; newattrs.ia_gid = gid; } - if (!S_ISDIR(inode->i_mode)) - newattrs.ia_valid |= - ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; inode_lock(inode); + if (!S_ISDIR(inode->i_mode)) + newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV | + setattr_should_drop_sgid(inode); error = security_path_chown(path, uid, gid); if (!error) error = notify_change(path->dentry, &newattrs, &delegated_inode); diff --git a/include/linux/fs.h b/include/linux/fs.h index 527791e4860b..57afa4fa5e7b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2960,7 +2960,7 @@ extern void __destroy_inode(struct inode *); extern struct inode *new_inode_pseudo(struct super_block *sb); extern struct inode *new_inode(struct super_block *sb); extern void free_inode_nonrcu(struct inode *inode); -extern int should_remove_suid(struct dentry *); +extern int setattr_should_drop_suidgid(struct inode *); extern int file_remove_privs(struct file *);

extern void __insert_inode_hash(struct inode *, unsigned long hashval);

From: Gaosheng Cui cuigaosheng1@huawei.com

commit b0463b9dd7030a766133ad2f1571f97f204d7bdf upstream.

xfs_setattr_time() has been removed since commit e014f37db1a2 ("xfs: use setattr_copy to set vfs inode attributes"), so remove it.

Signed-off-by: Gaosheng Cui cuigaosheng1@huawei.com Reviewed-by: Carlos Maiolino cmaiolino@redhat.com Signed-off-by: Dave Chinner david@fromorbit.com Signed-off-by: Amir Goldstein amir73il@gmail.com --- fs/xfs/xfs_iops.h | 1 - 1 file changed, 1 deletion(-)

diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h index 4d24ff309f59..dd1bd0332f8e 100644 --- a/fs/xfs/xfs_iops.h +++ b/fs/xfs/xfs_iops.h @@ -18,7 +18,6 @@ extern ssize_t xfs_vn_listxattr(struct dentry *, char *data, size_t size); */ #define XFS_ATTR_NOACL 0x01 /* Don't call posix_acl_chmod */

-extern void xfs_setattr_time(struct xfs_inode *ip, struct iattr *iattr); extern int xfs_setattr_nonsize(struct xfs_inode *ip, struct iattr *vap, int flags); extern int xfs_vn_setattr_nonsize(struct dentry *dentry, struct iattr *vap);