[PATCH AUTOSEL 5.10 04/25] NFSv4.1: Fix uninitialised variable in devicenotify

Sasha Levin
2022-02-03T20:38:34Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit b05bf5c63b326ce1da84ef42498d8e0e292e694c ]

When decode_devicenotify_args() exits with no entries, we need to
ensure that the struct cb_devicenotifyargs is initialised to
{ 0, NULL } in order to avoid problems in
nfs4_callback_devicenotify().

Reported-by: <rtm@csail.mit.edu>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/callback.h | 2 +-
fs/nfs/callback_proc.c | 2 +-
fs/nfs/callback_xdr.c | 18 +++++++++---------
3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
index 6a2033131c068..ccd4f245cae24 100644
--- a/fs/nfs/callback.h
+++ b/fs/nfs/callback.h
@@ -170,7 +170,7 @@ struct cb_devicenotifyitem {
};

struct cb_devicenotifyargs {
- int ndevs;
+ uint32_t ndevs;
struct cb_devicenotifyitem *devs;
};

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index be546ece383f5..b44219ce60b86 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -353,7 +353,7 @@ __be32 nfs4_callback_devicenotify(void *argp, void *resp,
struct cb_process_state *cps)
{
struct cb_devicenotifyargs *args = argp;
- int i;
+ uint32_t i;
__be32 res = 0;
struct nfs_client *clp = cps->clp;
struct nfs_server *server = NULL;
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 79ff172eb1c81..1725079a05276 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -259,11 +259,9 @@ __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
void *argp)
{
struct cb_devicenotifyargs *args = argp;
+ uint32_t tmp, n, i;
__be32 *p;
__be32 status = 0;
- u32 tmp;
- int n, i;
- args->ndevs = 0;

/* Num of device notifications */
p = xdr_inline_decode(xdr, sizeof(uint32_t));
@@ -272,7 +270,7 @@ __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
goto out;
}
n = ntohl(*p++);
- if (n <= 0)
+ if (n == 0)
goto out;
if (n > ULONG_MAX / sizeof(*args->devs)) {
status = htonl(NFS4ERR_BADXDR);
@@ -331,19 +329,21 @@ __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
dev->cbd_immediate = 0;
}

- args->ndevs++;
-
dprintk("%s: type %d layout 0x%x immediate %d\n",
__func__, dev->cbd_notify_type, dev->cbd_layout_type,
dev->cbd_immediate);
}
+ args->ndevs = n;
+ dprintk("%s: ndevs %d\n", __func__, args->ndevs);
+ return 0;
+err:
+ kfree(args->devs);
out:
+ args->devs = NULL;
+ args->ndevs = 0;
dprintk("%s: status %d ndevs %d\n",
__func__, ntohl(status), args->ndevs);
return status;
-err:
- kfree(args->devs);
- goto out;
}

static __be32 decode_sessionid(struct xdr_stream *xdr,
--
2.34.1