Date: Mon, 4 Mar 2024 18:51:46 GMT From: "Jason A. Harmening" <jah@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: c18e6a5a5c63 - stable/14 - unionfs: work around underlying FS failing to respect cn_namelen Message-ID: <202403041851.424IpkxK009631@gitrepo.freebsd.org>
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The branch stable/14 has been updated by jah: URL: https://cgit.FreeBSD.org/src/commit/?id=c18e6a5a5c63d85d664d60dc3bf0232ea21bf8d2 commit c18e6a5a5c63d85d664d60dc3bf0232ea21bf8d2 Author: Jason A. Harmening <jah@FreeBSD.org> AuthorDate: 2023-12-24 04:48:19 +0000 Commit: Jason A. Harmening <jah@FreeBSD.org> CommitDate: 2024-03-04 18:31:25 +0000 unionfs: work around underlying FS failing to respect cn_namelen unionfs_mkshadowdir() may be invoked on a non-leaf pathname component during lookup, in which case the NUL terminator of the pathname buffer will be well beyond the end of the current component. cn_namelen in this case will still (correctly) indicate the length of only the current component, but ZFS in particular does not currently respect cn_namelen, leading to the creation on inacessible files with slashes in their names. Work around this behavior by temporarily NUL- terminating the current pathname component for the call to VOP_MKDIR(). https://github.com/openzfs/zfs/issues/15705 has been filed to track a proper upstream fix for the issue at hand. PR: 275871 Reported by: Karlo Miličević <karlo98.m@gmail.com> Tested by: Karlo Miličević <karlo98.m@gmail.com> Reviewed by: kib, olce Differential Revision: https://reviews.freebsd.org/D43818 (cherry picked from commit a2ddbe019d51b35f9da2cb5ddca8c69f0ee422da) --- sys/fs/unionfs/union_subr.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/sys/fs/unionfs/union_subr.c b/sys/fs/unionfs/union_subr.c index c841136e42d5..469ba0775e7c 100644 --- a/sys/fs/unionfs/union_subr.c +++ b/sys/fs/unionfs/union_subr.c @@ -918,7 +918,24 @@ unionfs_mkshadowdir(struct unionfs_mount *ump, struct vnode *udvp, goto unionfs_mkshadowdir_abort; unionfs_create_uppervattr_core(ump, &lva, &va, td); + /* + * Temporarily NUL-terminate the current pathname component. + * This function may be called during lookup operations in which + * the current pathname component is not the leaf, meaning that + * the NUL terminator is some distance beyond the end of the current + * component. This *should* be fine, as cn_namelen will still + * correctly indicate the length of only the current component, + * but ZFS in particular does not respect cn_namelen in its VOP_MKDIR + * implementation + * Note that this assumes nd.ni_cnd.cn_pnbuf was allocated by + * something like a local namei() operation and the temporary + * NUL-termination will not have an effect on other threads. + */ + char *pathend = &nd.ni_cnd.cn_nameptr[nd.ni_cnd.cn_namelen]; + char pathterm = *pathend; + *pathend = '\0'; error = VOP_MKDIR(udvp, &uvp, &nd.ni_cnd, &va); + *pathend = pathterm; if (!error) { unionfs_node_update(unp, uvp, td);
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