The patch below does not apply to the 3.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e911b8158ee1def8153849b1641b736026b036e0 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <[email protected]> Date: Wed, 26 Mar 2014 13:24:37 -0700 Subject: [PATCH] NFSv4: Fix a use-after-free problem in open() 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 <[email protected]> Cc: [email protected] # 3.5+ Signed-off-by: Trond Myklebust <[email protected]> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index c866e325577f..397be39c6dc8 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); } @@ -2304,10 +2305,12 @@ 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) @@ -2335,11 +2338,10 @@ 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); @@ -2349,7 +2351,6 @@ 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); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
