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>

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index c4e7d15..ea0eaca 100644 (file)
--- 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;