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NFS: Fix use-after-free issues in nfs_pageio_add_request()

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We need to ensure that we create the mirror requests before calling
nfs_pageio_add_request_mirror() on the request we are adding.
Otherwise, we can end up with a use-after-free if the call to
nfs_pageio_add_request_mirror() triggers I/O.

Fixes: c917cfaf9b ("NFS: Fix up NFS I/O subrequest creation")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2020-03-29 19:55:05 -04:00
parent 08ca8b21f7
commit dc9dc2febb
1 changed files with 21 additions and 21 deletions
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12
fs/nfs/pagelist.c
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@ -1191,8 +1191,8 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
if (desc->pg_error < 0)
goto out_failed;
for (midx = 0; midx < desc->pg_mirror_count; midx++) {
if (midx) {
/* Create the mirror instances first, and fire them off */
for (midx = 1; midx < desc->pg_mirror_count; midx++) {
nfs_page_group_lock(req);
/* find the last request */
@ -1209,19 +1209,19 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
desc->pg_error = PTR_ERR(dupreq);
goto out_failed;
}
} else
dupreq = req;
if (nfs_pgio_has_mirroring(desc))
desc->pg_mirror_idx = midx;
if (!nfs_pageio_add_request_mirror(desc, dupreq))
goto out_cleanup_subreq;
}
desc->pg_mirror_idx = 0;
if (!nfs_pageio_add_request_mirror(desc, req))
goto out_failed;
return 1;
out_cleanup_subreq:
if (req != dupreq)
nfs_pageio_cleanup_request(desc, dupreq);
out_failed:
nfs_pageio_error_cleanup(desc);