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| author | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-12-29 01:30:05 +0100 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-12-29 01:37:05 +0100 |
| commit | 5c5fc09a1157a11dbe84e6421c3e0b37d05238cb (patch) | |
| tree | 7a8e69867e323744d7431d50d73e479615f93595 /fs/nfs | |
| parent | NFS: Flush reclaim writes using FLUSH_COND_STABLE (diff) | |
| download | linux-5c5fc09a1157a11dbe84e6421c3e0b37d05238cb.tar.xz linux-5c5fc09a1157a11dbe84e6421c3e0b37d05238cb.zip | |
NFS: Ensure we revalidate attributes before using execute_ok()
Donald Buczek reports that NFS clients can also report incorrect
results for access() due to lack of revalidation of attributes
before calling execute_ok().
Looking closely, it seems chdir() is afflicted with the same problem.
Fix is to ensure we call nfs_revalidate_inode_rcu() or
nfs_revalidate_inode() as appropriate before deciding to trust
execute_ok().
Reported-by: Donald Buczek <buczek@molgen.mpg.de>
Link: http://lkml.kernel.org/r/1451331530-3748-1-git-send-email-buczek@molgen.mpg.de
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs')
| -rw-r--r-- | fs/nfs/dir.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 44e519c21e18..5bd2f5bfaf57 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -2432,6 +2432,20 @@ int nfs_may_open(struct inode *inode, struct rpc_cred *cred, int openflags) } EXPORT_SYMBOL_GPL(nfs_may_open); +static int nfs_execute_ok(struct inode *inode, int mask) +{ + struct nfs_server *server = NFS_SERVER(inode); + int ret; + + if (mask & MAY_NOT_BLOCK) + ret = nfs_revalidate_inode_rcu(server, inode); + else + ret = nfs_revalidate_inode(server, inode); + if (ret == 0 && !execute_ok(inode)) + ret = -EACCES; + return ret; +} + int nfs_permission(struct inode *inode, int mask) { struct rpc_cred *cred; @@ -2484,8 +2498,8 @@ force_lookup: res = PTR_ERR(cred); } out: - if (!res && (mask & MAY_EXEC) && !execute_ok(inode)) - res = -EACCES; + if (!res && (mask & MAY_EXEC)) + res = nfs_execute_ok(inode, mask); dfprintk(VFS, "NFS: permission(%s/%lu), mask=0x%x, res=%d\n", inode->i_sb->s_id, inode->i_ino, mask, res); |