Date: Sun, 3 Jan 2021 06:53:12 GMT From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 30a2fc91fa5a - main - cache: postpone NAME_MAX check as it may be unnecessary Message-ID: <202101030653.1036rCbO023169@gitrepo.freebsd.org>
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The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=30a2fc91fa5a0fa8717da788cc18073cca786c05 commit 30a2fc91fa5a0fa8717da788cc18073cca786c05 Author: Mateusz Guzik <mjg@FreeBSD.org> AuthorDate: 2020-12-31 07:28:32 +0000 Commit: Mateusz Guzik <mjg@FreeBSD.org> CommitDate: 2021-01-03 06:50:06 +0000 cache: postpone NAME_MAX check as it may be unnecessary --- sys/kern/vfs_cache.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c index e6f446d2d0e2..b4882079790d 100644 --- a/sys/kern/vfs_cache.c +++ b/sys/kern/vfs_cache.c @@ -2230,6 +2230,9 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, int flag; int len; + KASSERT(cnp->cn_namelen <= NAME_MAX, + ("%s: passed len %ld exceeds NAME_MAX (%d)", __func__, cnp->cn_namelen, + NAME_MAX)); VNPASS(dvp != vp, dvp); VNPASS(!VN_IS_DOOMED(dvp), dvp); VNPASS(dvp->v_type != VNON, dvp); @@ -4310,6 +4313,14 @@ cache_fplookup_noentry(struct cache_fpl *fpl) MPASS((cnp->cn_flags & ISDOTDOT) == 0); MPASS(!cache_fpl_isdotdot(cnp)); + /* + * Hack: delayed name len checking. + */ + if (__predict_false(cnp->cn_namelen > NAME_MAX)) { + cache_fpl_smr_exit(fpl); + return (cache_fpl_handled(fpl, ENAMETOOLONG)); + } + if (cnp->cn_nameiop != LOOKUP) { fpl->tvp = NULL; return (cache_fplookup_modifying(fpl)); @@ -4834,13 +4845,15 @@ cache_fplookup_parse(struct cache_fpl *fpl) cnp->cn_nameptr[ndp->ni_pathlen - 1] = '\0'; cnp->cn_namelen = cp - cnp->cn_nameptr; - if (__predict_false(cnp->cn_namelen > NAME_MAX)) { - cache_fpl_smr_exit(fpl); - return (cache_fpl_handled(fpl, ENAMETOOLONG)); - } ndp->ni_pathlen -= cnp->cn_namelen; KASSERT(ndp->ni_pathlen <= PATH_MAX, ("%s: ni_pathlen underflow to %zd\n", __func__, ndp->ni_pathlen)); + /* + * Hack: we have to check if the found path component's length exceeds + * NAME_MAX. However, the condition is very rarely true and check can + * be elided in the common case -- if an entry was found in the cache, + * then it could not have been too long to begin with. + */ ndp->ni_next = cp; #ifdef INVARIANTS @@ -4888,12 +4901,22 @@ cache_fplookup_parse_advance(struct cache_fpl *fpl) static int __noinline cache_fplookup_failed_vexec(struct cache_fpl *fpl, int error) { + struct componentname *cnp; struct vnode *dvp; seqc_t dvp_seqc; + cnp = fpl->cnp; dvp = fpl->dvp; dvp_seqc = fpl->dvp_seqc; + /* + * Hack: delayed name len checking. + */ + if (__predict_false(cnp->cn_namelen > NAME_MAX)) { + cache_fpl_smr_exit(fpl); + return (cache_fpl_handled(fpl, ENAMETOOLONG)); + } + /* * Hack: they may be looking up foo/bar, where foo is a * regular file. In such a case we need to turn ENOTDIR,
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