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authorTrond Myklebust <trond.myklebust@primarydata.com>2015-12-29 01:30:05 +0100
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-12-29 01:37:05 +0100
commit5c5fc09a1157a11dbe84e6421c3e0b37d05238cb (patch)
tree7a8e69867e323744d7431d50d73e479615f93595 /fs/nfs/dir.c
parentNFS: Flush reclaim writes using FLUSH_COND_STABLE (diff)
downloadlinux-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/dir.c')
-rw-r--r--fs/nfs/dir.c18
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);