nfsd: more careful input validation in nfsctl write methods
Neil Brown points out that we're checking buf[size-1] in a couple places
without first checking whether size is zero.
Actually, given the implementation of simple_transaction_get(), buf[-1]
is zero, so in both of these cases the subsequent check of the value of
buf[size-1] will catch this case.
But it seems fragile to depend on that, so add explicit checks for this
case.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Acked-by: NeilBrown <neilb@suse.de>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index bc22e0b..8516137 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -304,6 +304,9 @@
struct auth_domain *dom;
struct knfsd_fh fh;
+ if (size == 0)
+ return -EINVAL;
+
if (buf[size-1] != '\n')
return -EINVAL;
buf[size-1] = 0;
@@ -663,7 +666,7 @@
char *recdir;
int len, status;
- if (size > PATH_MAX || buf[size-1] != '\n')
+ if (size == 0 || size > PATH_MAX || buf[size-1] != '\n')
return -EINVAL;
buf[size-1] = 0;
