The branch main has been updated by mjg:
URL:
https://cgit.FreeBSD.org/src/commit/?id=30a2fc91fa5a0fa8717da788cc18073cca786c05
commit 30a2fc91fa5a0fa8717da788cc18073cca786c05
Author: Mateusz Guzik <m...@freebsd.org>
AuthorDate: 2020-12-31 07:28:32 +0000
Commit: Mateusz Guzik <m...@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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