mail archive of the barebox mailing list
 help / color / mirror / Atom feed
From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH v2] nfs: check return value of various rpc calls
Date: Tue,  3 Nov 2020 21:09:32 +0100	[thread overview]
Message-ID: <20201103200932.18824-1-u.kleine-koenig@pengutronix.de> (raw)

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@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


_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox

             reply	other threads:[~2020-11-03 20:09 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-03 20:09 Uwe Kleine-König [this message]
2020-11-09  9:02 ` Sascha Hauer
2020-11-09 14:37   ` Gavin Schenk
2020-11-09 16:09     ` Sascha Hauer

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201103200932.18824-1-u.kleine-koenig@pengutronix.de \
    --to=u.kleine-koenig@pengutronix.de \
    --cc=barebox@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox