POSIX states that open("foo", O_CREAT|O_RDONLY, 000) should succeed if
the file "foo" does not already exist. With the current NFS client,
it will fail with an EACCES error because of the permissions checks in
nfs4_opendata_access().
Fix is to turn that test off if the server says that we created the file.
Reported-by: "Frank S. Filz" <ffilzlnx@xxxxxxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfs/nfs4proc.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d0e0e54fb2b9..70e53a2ac75e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1954,6 +1954,14 @@ static int _nfs4_recover_proc_open(struct nfs4_opendata *data)
return status;
}
+/*
+ * Additional permission checks in order to distinguish between an
+ * open for read, and an open for execute. This works around the
+ * fact that NFSv4 OPEN treats read and execute permissions as being
+ * the same.
+ * Note that in the non-execute case, we want to turn off permission
+ * checking if we just created a new file (POSIX open() semantics).
+ */
static int nfs4_opendata_access(struct rpc_cred *cred,
struct nfs4_opendata *opendata,
struct nfs4_state *state, fmode_t fmode,
@@ -1968,14 +1976,14 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
return 0;
mask = 0;
- /* don't check MAY_WRITE - a newly created file may not have
- * write mode bits, but POSIX allows the creating process to write.
- * use openflags to check for exec, because fmode won't
- * always have FMODE_EXEC set when file open for exec. */
+ /*
+ * Use openflags to check for exec, because fmode won't
+ * always have FMODE_EXEC set when file open for exec.
+ */
if (openflags & __FMODE_EXEC) {
/* ONLY check for exec rights */
mask = MAY_EXEC;
- } else if (fmode & FMODE_READ)
+ } else if ((fmode & FMODE_READ) && !opendata->file_created)
mask = MAY_READ;
cache.cred = cred;
--
1.9.3
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
