| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.18 184/339] NFSD: Fix potential use-after-free in nfsd_file_put() | Date | Mon, 13 Jun 2022 12:10:09 +0200 |
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From: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit b6c71c66b0ad8f2b59d9bc08c7a5079b110bec01 ]
nfsd_file_put_noref() can free @nf, so don't dereference @nf immediately upon return from nfsd_file_put_noref().
Suggested-by: Trond Myklebust <trondmy@hammerspace.com> Fixes: 999397926ab3 ("nfsd: Clean up nfsd_file_put()") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/nfsd/filecache.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index 2c1b027774d4..0326bdec5de7 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -306,11 +306,12 @@ nfsd_file_put(struct nfsd_file *nf) if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0) { nfsd_file_flush(nf); nfsd_file_put_noref(nf); - } else { + } else if (nf->nf_file) { nfsd_file_put_noref(nf); - if (nf->nf_file) - nfsd_file_schedule_laundrette(); - } + nfsd_file_schedule_laundrette(); + } else + nfsd_file_put_noref(nf); + if (atomic_long_read(&nfsd_filecache_count) >= NFSD_FILE_LRU_LIMIT) nfsd_file_gc(); } -- 2.35.1
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