1 files changed, 12 insertions, 2 deletions
diff --git a/libpam/pam_modutil_ioloop.c b/libpam/pam_modutil_ioloop.c
index 54ab0e55..72b58455 100644
--- a/libpam/pam_modutil_ioloop.c
+++ b/libpam/pam_modutil_ioloop.c
@@ -1,8 +1,8 @@
 /*
  * $Id$
  *
- * These functions provides common methods for ensure a complete read or
- * write occurs. It handles EINTR and partial read/write returns.
+ * These functions provide common methods to ensure a complete read or
+ * write occurs. They handle EINTR and partial read/write returns.
  */
 
 #include "pam_modutil_private.h"
@@ -15,6 +15,11 @@ pam_modutil_read(int fd, char *buffer, int count)
 {
        int block, offset = 0;
 
+       if (count < 0) {
+               errno = EINVAL;
+               return -1;
+       }
+
        while (count > 0) {
                block = read(fd, &buffer[offset], count);
 
@@ -36,6 +41,11 @@ pam_modutil_write(int fd, const char *buffer, int count)
 {
        int block, offset = 0;
 
+       if (count < 0) {
+               errno = EINVAL;
+               return -1;
+       }
+
        while (count > 0) {
                block = write(fd, &buffer[offset], count);