diff options
| author | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-03-26 13:24:37 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-06 07:59:27 -0700 |
| commit | dbeeb36eb6046aa44004d4ee2077f3e84b1979d3 (patch) | |
| tree | 98977a2547ae4a4e720fcdf0d04b004d8dae54c7 /fs/nfs | |
| parent | 9a64345f0369251f2841bccec8054f5bdb2b673b (diff) | |
| download | lwn-dbeeb36eb6046aa44004d4ee2077f3e84b1979d3.tar.gz lwn-dbeeb36eb6046aa44004d4ee2077f3e84b1979d3.zip | |
NFSv4: Fix a use-after-free problem in open()
commit e911b8158ee1def8153849b1641b736026b036e0 upstream.
If we interrupt the nfs4_wait_for_completion_rpc_task() call in
nfs4_run_open_task(), then we don't prevent the RPC call from
completing. So freeing up the opendata->f_attr.mdsthreshold
in the error path in _nfs4_do_open() leads to a use-after-free
when the XDR decoder tries to decode the mdsthreshold information
from the server.
Fixes: 82be417aa37c0 (NFSv4.1 cache mdsthreshold values on OPEN)
Tested-by: Steve Dickson <SteveD@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/nfs')
| -rw-r--r-- | fs/nfs/nfs4proc.c | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 450bfedbe2f4..d5d06e868841 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -1068,6 +1068,7 @@ static void nfs4_opendata_free(struct kref *kref) dput(p->dentry); nfs_sb_deactive(sb); nfs_fattr_free_names(&p->f_attr); + kfree(p->f_attr.mdsthreshold); kfree(p); } @@ -2244,10 +2245,12 @@ static int _nfs4_do_open(struct inode *dir, } } - if (ctx_th && server->attr_bitmask[2] & FATTR4_WORD2_MDSTHRESHOLD) { - opendata->f_attr.mdsthreshold = pnfs_mdsthreshold_alloc(); - if (!opendata->f_attr.mdsthreshold) - goto err_free_label; + if (server->attr_bitmask[2] & FATTR4_WORD2_MDSTHRESHOLD) { + if (!opendata->f_attr.mdsthreshold) { + opendata->f_attr.mdsthreshold = pnfs_mdsthreshold_alloc(); + if (!opendata->f_attr.mdsthreshold) + goto err_free_label; + } opendata->o_arg.open_bitmap = &nfs4_pnfs_open_bitmap[0]; } if (dentry->d_inode != NULL) @@ -2275,11 +2278,10 @@ static int _nfs4_do_open(struct inode *dir, if (opendata->file_created) *opened |= FILE_CREATED; - if (pnfs_use_threshold(ctx_th, opendata->f_attr.mdsthreshold, server)) + if (pnfs_use_threshold(ctx_th, opendata->f_attr.mdsthreshold, server)) { *ctx_th = opendata->f_attr.mdsthreshold; - else - kfree(opendata->f_attr.mdsthreshold); - opendata->f_attr.mdsthreshold = NULL; + opendata->f_attr.mdsthreshold = NULL; + } nfs4_label_free(olabel); @@ -2289,7 +2291,6 @@ static int _nfs4_do_open(struct inode *dir, err_free_label: nfs4_label_free(olabel); err_opendata_put: - kfree(opendata->f_attr.mdsthreshold); nfs4_opendata_put(opendata); err_put_state_owner: nfs4_put_state_owner(sp); |