modpost: Stop grab_file() from leaking filedescriptors if fstat() fails

In case the open() call succeeds but the subsequent fstat() call
fails, then we'll return without close()'ing the filedescriptor.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 6 insertions, 3 deletions

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index c4e7d1510f9d..ea0eaca597b9 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -337,17 +337,20 @@ static void sym_update_crc(const char *name, struct module *mod,
 void *grab_file(const char *filename, unsigned long *size)
 {
         struct stat st;
-        void *map;
+        void *map = MAP_FAILED;
         int fd;
 
         fd = open(filename, O_RDONLY);
-        if (fd < 0 || fstat(fd, &st) != 0)
+        if (fd < 0)
                 return NULL;
+        if (fstat(fd, &st))
+                goto failed;
 
         *size = st.st_size;
         map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
-        close(fd);
 
+failed:
+        close(fd);
         if (map == MAP_FAILED)
                 return NULL;
         return map;