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authorLinus Torvalds <torvalds@linux-foundation.org>2023-01-24 12:58:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2023-01-24 12:58:47 -0800
commitfb6e71db53f3d4351dada7c130fb652eecf994d6 (patch)
treef2c156ea6c94a74c278479e7d4be2f7032a8441c /fs
parent50306df38ac4edbeb1eac29d68128f84630405d8 (diff)
parent4bdbba54e9b1c769da8ded9abd209d765715e1d6 (diff)
Merge tag 'nfsd-6.2-5' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux
Pull nfsd fix from Chuck Lever: - Nail another UAF in NFSD's filecache * tag 'nfsd-6.2-5' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: nfsd: don't free files unconditionally in __nfsd_file_cache_purge
Diffstat (limited to 'fs')
-rw-r--r--fs/nfsd/filecache.c61
1 files changed, 36 insertions, 25 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 0ef070349014..c0950edb26b0 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -662,6 +662,39 @@ static struct shrinker nfsd_file_shrinker = {
};
/**
+ * nfsd_file_cond_queue - conditionally unhash and queue a nfsd_file
+ * @nf: nfsd_file to attempt to queue
+ * @dispose: private list to queue successfully-put objects
+ *
+ * Unhash an nfsd_file, try to get a reference to it, and then put that
+ * reference. If it's the last reference, queue it to the dispose list.
+ */
+static void
+nfsd_file_cond_queue(struct nfsd_file *nf, struct list_head *dispose)
+ __must_hold(RCU)
+{
+ int decrement = 1;
+
+ /* If we raced with someone else unhashing, ignore it */
+ if (!nfsd_file_unhash(nf))
+ return;
+
+ /* If we can't get a reference, ignore it */
+ if (!nfsd_file_get(nf))
+ return;
+
+ /* Extra decrement if we remove from the LRU */
+ if (nfsd_file_lru_remove(nf))
+ ++decrement;
+
+ /* If refcount goes to 0, then put on the dispose list */
+ if (refcount_sub_and_test(decrement, &nf->nf_ref)) {
+ list_add(&nf->nf_lru, dispose);
+ trace_nfsd_file_closing(nf);
+ }
+}
+
+/**
* nfsd_file_queue_for_close: try to close out any open nfsd_files for an inode
* @inode: inode on which to close out nfsd_files
* @dispose: list on which to gather nfsd_files to close out
@@ -688,30 +721,11 @@ nfsd_file_queue_for_close(struct inode *inode, struct list_head *dispose)
rcu_read_lock();
do {
- int decrement = 1;
-
nf = rhashtable_lookup(&nfsd_file_rhash_tbl, &key,
nfsd_file_rhash_params);
if (!nf)
break;
-
- /* If we raced with someone else unhashing, ignore it */
- if (!nfsd_file_unhash(nf))
- continue;
-
- /* If we can't get a reference, ignore it */
- if (!nfsd_file_get(nf))
- continue;
-
- /* Extra decrement if we remove from the LRU */
- if (nfsd_file_lru_remove(nf))
- ++decrement;
-
- /* If refcount goes to 0, then put on the dispose list */
- if (refcount_sub_and_test(decrement, &nf->nf_ref)) {
- list_add(&nf->nf_lru, dispose);
- trace_nfsd_file_closing(nf);
- }
+ nfsd_file_cond_queue(nf, dispose);
} while (1);
rcu_read_unlock();
}
@@ -928,11 +942,8 @@ __nfsd_file_cache_purge(struct net *net)
nf = rhashtable_walk_next(&iter);
while (!IS_ERR_OR_NULL(nf)) {
- if (!net || nf->nf_net == net) {
- nfsd_file_unhash(nf);
- nfsd_file_lru_remove(nf);
- list_add(&nf->nf_lru, &dispose);
- }
+ if (!net || nf->nf_net == net)
+ nfsd_file_cond_queue(nf, &dispose);
nf = rhashtable_walk_next(&iter);
}