[PATCH v2] nfs: check return value of various rpc calls
Uwe Kleine-König
u.kleine-koenig at pengutronix.de
Tue Nov 3 15:09:32 EST 2020
Check more carefully for failing requests. This improves the error
message when trying to mount a non-exported nfs directory from:
nfs_mount_req: file handle too big: 44831
to
nfs_mount_req: Mounting failed: NFS3ERR_ACCES(0xd)
. This also fixes an out-of-bounds access as the filehandle size (44831
above) is read from just after the network packet in the error case.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
Hello,
while working on this patch I decided to keep the error name constants
and so deviate from what I promised in reply to Sascha's feedback for
v1. The reason is that not all NFS error constants have a corresponding
POSIX error code and so pretty printing the error might be helpful.
Best regards
Uwe
fs/nfs.c | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 102 insertions(+), 10 deletions(-)
diff --git a/fs/nfs.c b/fs/nfs.c
index 15ddab7915df..1f60cbad4045 100644
--- a/fs/nfs.c
+++ b/fs/nfs.c
@@ -636,13 +636,82 @@ static uint32_t *nfs_read_post_op_attr(uint32_t *p, struct inode *inode)
return p;
}
+static int nfserror_to_err(u32 nfserror, const char **errorname)
+{
+ /*
+ * Most NFS errors have a corresponding POSIX error code. But not all of
+ * them have one, so some must be mapped to a different code here.
+ * To get helpful error messages also keep string constants for the
+ * actual errors. They are stored without the common NFS3ERR_ prefix to
+ * save some memory.
+ */
+#define E(NFSERR, ERR) \
+ case NFS3ERR_ ## NFSERR: \
+ *errorname = #NFSERR; \
+ return -ERR
+
+ switch (nfserror) {
+ E(PERM, EPERM);
+ E(NOENT, ENOENT);
+ E(IO, EIO);
+ E(NXIO, ENXIO);
+ E(ACCES, EACCES);
+ E(EXIST, EEXIST);
+ E(XDEV, EXDEV);
+ E(NODEV, ENODEV);
+ E(NOTDIR, ENOTDIR);
+ E(ISDIR, EISDIR);
+ E(INVAL, EINVAL);
+ E(FBIG, EFBIG);
+ E(NOSPC, ENOSPC);
+ E(ROFS, EROFS);
+ E(MLINK, EMLINK);
+ E(NAMETOOLONG, ENAMETOOLONG);
+ E(NOTEMPTY, ENOTEMPTY);
+ E(DQUOT, EDQUOT);
+ E(STALE, ESTALE);
+ E(REMOTE, EREMOTE);
+ E(BADHANDLE, EINVAL);
+ E(NOT_SYNC, EINVAL);
+ E(BAD_COOKIE, EINVAL);
+ E(NOTSUPP, ENOTSUPP);
+ E(TOOSMALL, EINVAL);
+ E(SERVERFAULT, EINVAL);
+ E(BADTYPE, EINVAL);
+ E(JUKEBOX, EINVAL);
+
+ default:
+ *errorname = "???";
+ return -EINVAL;
+ }
+}
+
+static int nfs_printerr(u32 nfserror, const char *fmt, ...)
+{
+ va_list args;
+ const char *errorname;
+ int ret;
+
+ va_start(args, fmt);
+
+ vprintf(fmt, args);
+
+ va_end(args);
+
+ ret = nfserror_to_err(nfserror, &errorname);
+
+ printf(": NFS3ERR_%s(0x%x)\n", errorname, (unsigned)nfserror);
+
+ return ret;
+}
+
/*
* nfs_mount_req - Mount an NFS Filesystem
*/
static int nfs_mount_req(struct nfs_priv *npriv)
{
uint32_t data[1024];
- uint32_t *p;
+ uint32_t *p, status;
int len;
int pathlen;
struct packet *nfs_packet;
@@ -667,7 +736,15 @@ static int nfs_mount_req(struct nfs_priv *npriv)
if (IS_ERR(nfs_packet))
return PTR_ERR(nfs_packet);
- p = (void *)nfs_packet->data + sizeof(struct rpc_reply) + 4;
+ p = (void *)nfs_packet->data + sizeof(struct rpc_reply);
+
+ /*
+ * Theoretically the error status is one of MNT3ERR_..., but the NFS
+ * constants are identical.
+ */
+ status = ntoh32(net_read_uint32(p++));
+ if (status != NFS3_OK)
+ return nfs_printerr(status, "%s: Mounting failed", __func__);
npriv->rootfh.size = ntoh32(net_read_uint32(p++));
if (npriv->rootfh.size > NFS3_FHSIZE) {
@@ -719,7 +796,7 @@ static int nfs_lookup_req(struct nfs_priv *npriv, struct nfs_fh *fh,
{
struct nfs_inode *ninode = nfsi(inode);
uint32_t data[1024];
- uint32_t *p;
+ uint32_t *p, status;
int len;
struct packet *nfs_packet;
@@ -761,7 +838,10 @@ static int nfs_lookup_req(struct nfs_priv *npriv, struct nfs_fh *fh,
if (IS_ERR(nfs_packet))
return PTR_ERR(nfs_packet);
- p = (void *)nfs_packet->data + sizeof(struct rpc_reply) + 4;
+ p = (void *)nfs_packet->data + sizeof(struct rpc_reply);
+ status = ntoh32(net_read_uint32(p++));
+ if (status != NFS3_OK)
+ return nfs_printerr(status, "%s: LOOKUP failed", __func__);
ninode->fh.size = ntoh32(net_read_uint32(p++));
if (ninode->fh.size > NFS3_FHSIZE) {
@@ -787,7 +867,7 @@ static int nfs_lookup_req(struct nfs_priv *npriv, struct nfs_fh *fh,
static void *nfs_readdirattr_req(struct nfs_priv *npriv, struct nfs_dir *dir)
{
uint32_t data[1024];
- uint32_t *p;
+ uint32_t *p, status;
int len;
struct packet *nfs_packet;
void *buf;
@@ -845,7 +925,13 @@ static void *nfs_readdirattr_req(struct nfs_priv *npriv, struct nfs_dir *dir)
if (IS_ERR(nfs_packet))
return NULL;
- p = (void *)nfs_packet->data + sizeof(struct rpc_reply) + 4;
+ p = (void *)nfs_packet->data + sizeof(struct rpc_reply);
+ status = ntoh32(net_read_uint32(p++));
+ if (status != NFS3_OK) {
+ nfs_printerr(status, "%s: READDIR failed", __func__);
+ return NULL;
+ }
+
p = nfs_read_post_op_attr(p, NULL);
/* update cookieverf */
@@ -879,7 +965,7 @@ static int nfs_read_req(struct file_priv *priv, uint64_t offset,
uint32_t readlen)
{
uint32_t data[1024];
- uint32_t *p;
+ uint32_t *p, status;
int len;
struct packet *nfs_packet;
uint32_t rlen, eof;
@@ -922,7 +1008,10 @@ static int nfs_read_req(struct file_priv *priv, uint64_t offset,
if (IS_ERR(nfs_packet))
return PTR_ERR(nfs_packet);
- p = (void *)nfs_packet->data + sizeof(struct rpc_reply) + 4;
+ p = (void *)nfs_packet->data + sizeof(struct rpc_reply);
+ status = ntoh32(net_read_uint32(p++));
+ if (status != NFS3_OK)
+ return nfs_printerr(status, "%s: READ failed", __func__);
p = nfs_read_post_op_attr(p, NULL);
@@ -981,7 +1070,7 @@ static int nfs_readlink_req(struct nfs_priv *npriv, struct nfs_fh *fh,
char **target)
{
uint32_t data[1024];
- uint32_t *p;
+ uint32_t *p, status;
uint32_t len;
struct packet *nfs_packet;
@@ -1017,7 +1106,10 @@ static int nfs_readlink_req(struct nfs_priv *npriv, struct nfs_fh *fh,
if (IS_ERR(nfs_packet))
return PTR_ERR(nfs_packet);
- p = (void *)nfs_packet->data + sizeof(struct rpc_reply) + 4;
+ p = (void *)nfs_packet->data + sizeof(struct rpc_reply);
+ status = ntoh32(net_read_uint32(p++));
+ if (status != NFS3_OK)
+ return nfs_printerr(status, "%s: READLINK failed", __func__);
p = nfs_read_post_op_attr(p, NULL);
--
2.28.0
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