don't pass -1 to fstat

Signed-off-by: Thanos Makatos <thanos.makatos@nutanix.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/dma.c b/lib/dma.c
index dd8087c..57c13e8 100644
--- a/lib/dma.c
+++ b/lib/dma.c
@@ -61,6 +61,11 @@ fds_are_same_file(int fd1, int fd2)
 {
     struct stat st1, st2;
 
+    if (fd1 == -1 || fd2 == -1) {
+        errno = EINVAL;
+        return -1;
+    }
+
     return (fstat(fd1, &st1) == 0 && fstat(fd2, &st2) == 0 &&
             st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
 }
@@ -206,6 +211,11 @@ dma_controller_add_region(dma_controller_t *dma,
     dma_memory_region_t *region;
     int page_size;
 
+    if (fd == -1) {
+        errno = EINVAL;
+        return -1;
+    }
+
     for (idx = 0; idx < dma->nregions; idx++) {
         region = &dma->regions[idx];