[patch] nfsd: oopses in cache_parse()

[Dan Carpenter]

We fixed expkey_parse() in b2ea70afad "nfsd: Fix oops when parsing a
0 length export" but there are other cache_parse() implimentations
which have the same issue.

Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
Since half of the implimentations get this wrong, maybe we should
just check for this in cache_do_downcall().  Is there ever a valid
reason to pass a zero length string to cache_parse()?

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index cf8a6bd..1d147a8 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -496,7 +496,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 	struct svc_export exp = {}, *expp;
 	int an_int;
 
-	if (mesg[mlen-1] != '\n')
+	if (mlen < 1 || mesg[mlen - 1] != '\n')
 		return -EINVAL;
 	mesg[mlen-1] = 0;
 
diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
index a6e711a..d945d71 100644
--- a/fs/nfs/dns_resolve.c
+++ b/fs/nfs/dns_resolve.c
@@ -217,7 +217,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
 	ssize_t len;
 	int ret = -EINVAL;
 
-	if (buf[buflen-1] != '\n')
+	if (buflen < 1 || buf[buflen - 1] != '\n')
 		goto out;
 	buf[buflen-1] = '\0';
 
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 9409627..f8456a4 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -202,7 +202,7 @@ idtoname_parse(struct cache_detail *cd, char *buf, int buflen)
 	int len;
 	int error = -EINVAL;
 
-	if (buf[buflen - 1] != '\n')
+	if (buflen < 1 || buf[buflen - 1] != '\n')
 		return (-EINVAL);
 	buf[buflen - 1]= '\0';
 
@@ -378,7 +378,7 @@ nametoid_parse(struct cache_detail *cd, char *buf, int buflen)
 	char *buf1;
 	int error = -EINVAL;
 
-	if (buf[buflen - 1] != '\n')
+	if (buflen < 1 || buf[buflen - 1] != '\n')
 		return (-EINVAL);
 	buf[buflen - 1]= '\0';

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