In nfs4_xdr_dec_cb_recall(), nfs4_xdr_dec_cb_layout() and
nfs4_xdr_dec_cb_notify_lock(), there is an if statement to check whether
cb is NULL.
When cb is NULL, the three functions all call:
decode_cb_op_status(..., &cb->cb_status);
Thus, possible null-pointer dereferences may occur.
To fix these possible bugs, -EINVAL is returned when cb is NULL.
These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <[email protected]>
---
fs/nfsd/nfs4callback.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 397eb7820929..55949a158b6b 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -516,7 +516,8 @@ static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
status = decode_cb_sequence4res(xdr, cb);
if (unlikely(status || cb->cb_seq_status))
return status;
- }
+ } else
+ return -EINVAL;
return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
}
@@ -608,7 +609,9 @@ static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
status = decode_cb_sequence4res(xdr, cb);
if (unlikely(status || cb->cb_seq_status))
return status;
- }
+ } else
+ return -EINVAL;
+
return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
}
#endif /* CONFIG_NFSD_PNFS */
@@ -667,7 +670,9 @@ static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
status = decode_cb_sequence4res(xdr, cb);
if (unlikely(status || cb->cb_seq_status))
return status;
- }
+ } else
+ return -EINVAL;
+
return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
}
--
2.17.0
On Tue, Jul 30, 2019 at 07:03:39PM -0400, J. Bruce Fields wrote:
> Thanks! But I think actually the correct fix is just to remove the NULL
> checks entirely.
So, something like the following (untested).--b.
commit 7ce38d2d8a66
Author: J. Bruce Fields <[email protected]>
Date: Tue Jul 30 19:06:38 2019 -0400
nfsd: Remove unnecessary NULL checks
"cb" is never actually NULL in these functions.
On a quick skim of the history, they seem to have been there from the
beginning. I'm not sure if they originally served a purpose.
Reported-by: Jia-Ju Bai <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 397eb7820929..524111420b48 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -512,11 +512,9 @@ static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
if (unlikely(status))
return status;
- if (cb != NULL) {
- status = decode_cb_sequence4res(xdr, cb);
- if (unlikely(status || cb->cb_seq_status))
- return status;
- }
+ status = decode_cb_sequence4res(xdr, cb);
+ if (unlikely(status || cb->cb_seq_status))
+ return status;
return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
}
@@ -604,11 +602,10 @@ static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
if (unlikely(status))
return status;
- if (cb) {
- status = decode_cb_sequence4res(xdr, cb);
- if (unlikely(status || cb->cb_seq_status))
- return status;
- }
+ status = decode_cb_sequence4res(xdr, cb);
+ if (unlikely(status || cb->cb_seq_status))
+ return status;
+
return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
}
#endif /* CONFIG_NFSD_PNFS */
@@ -663,11 +660,10 @@ static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
if (unlikely(status))
return status;
- if (cb) {
- status = decode_cb_sequence4res(xdr, cb);
- if (unlikely(status || cb->cb_seq_status))
- return status;
- }
+ status = decode_cb_sequence4res(xdr, cb);
+ if (unlikely(status || cb->cb_seq_status))
+ return status;
+
return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
}
@@ -759,11 +755,10 @@ static int nfs4_xdr_dec_cb_offload(struct rpc_rqst *rqstp,
if (unlikely(status))
return status;
- if (cb) {
- status = decode_cb_sequence4res(xdr, cb);
- if (unlikely(status || cb->cb_seq_status))
- return status;
- }
+ status = decode_cb_sequence4res(xdr, cb);
+ if (unlikely(status || cb->cb_seq_status))
+ return status;
+
return decode_cb_op_status(xdr, OP_CB_OFFLOAD, &cb->cb_status);
}
/*
On Wed, Jul 24, 2019 at 04:28:03PM +0800, Jia-Ju Bai wrote:
> In nfs4_xdr_dec_cb_recall(), nfs4_xdr_dec_cb_layout() and
> nfs4_xdr_dec_cb_notify_lock(), there is an if statement to check whether
> cb is NULL.
>
> When cb is NULL, the three functions all call:
> decode_cb_op_status(..., &cb->cb_status);
>
> Thus, possible null-pointer dereferences may occur.
>
> To fix these possible bugs, -EINVAL is returned when cb is NULL.
>
> These bugs are found by a static analysis tool STCheck written by us.
Thanks! But I think actually the correct fix is just to remove the NULL
checks entirely.
--b.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> ---
> fs/nfsd/nfs4callback.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index 397eb7820929..55949a158b6b 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -516,7 +516,8 @@ static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
> status = decode_cb_sequence4res(xdr, cb);
> if (unlikely(status || cb->cb_seq_status))
> return status;
> - }
> + } else
> + return -EINVAL;
>
> return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status);
> }
> @@ -608,7 +609,9 @@ static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp,
> status = decode_cb_sequence4res(xdr, cb);
> if (unlikely(status || cb->cb_seq_status))
> return status;
> - }
> + } else
> + return -EINVAL;
> +
> return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status);
> }
> #endif /* CONFIG_NFSD_PNFS */
> @@ -667,7 +670,9 @@ static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp,
> status = decode_cb_sequence4res(xdr, cb);
> if (unlikely(status || cb->cb_seq_status))
> return status;
> - }
> + } else
> + return -EINVAL;
> +
> return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status);
> }
>
> --
> 2.17.0