ANDROID: mm/memfd-ashmem-shim: Fix variable length array usage
The size of the buffer used to retrieve the memfd file name is
currently calculated at runtime, making the buffer a variable
length array. However, all of the terms used in the buffer size
calculation are known at compile time, so use compile time constants
for the calculation.
Bug: 399839316
Change-Id: Ie1edf9a28f735ebeffab07f64efc4de45f1f095a
Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com>
diff --git a/mm/memfd-ashmem-shim.c b/mm/memfd-ashmem-shim.c
index 8c7016b..e09d95a 100644
--- a/mm/memfd-ashmem-shim.c
+++ b/mm/memfd-ashmem-shim.c
@@ -17,10 +17,12 @@
#include "memfd-ashmem-shim-internal.h"
/* file_path() returns the path of the file including the root, hence the additional "/". */
-#define MEMFD_PATH_PREFIX_LEN strlen("/memfd:")
+#define MEMFD_PATH_PREFIX "/memfd:"
+#define MEMFD_PATH_PREFIX_LEN (sizeof(MEMFD_PATH_PREFIX) - 1)
/* All memfd files are unlinked, and are therefore suffixed with the " (deleted)" string. */
-#define UNLINKED_FILE_SUFFIX_LEN strlen(" (deleted)")
+#define UNLINKED_FILE_SUFFIX " (deleted)"
+#define UNLINKED_FILE_SUFFIX_LEN (sizeof(UNLINKED_FILE_SUFFIX) - 1)
/*
* 1 character for the start of the path (/), NAME_MAX for the maximum length of a full memfd file
@@ -38,8 +40,8 @@ static char *get_memfd_file_name(struct file *file, char *buf, size_t size)
return path;
/* Only handle memfds; we cannot make assumptions about other file names. */
- name_end = strstr(path, " (deleted)");
- if ((strstr(path, "/memfd:") != path) || !name_end)
+ name_end = strstr(path, UNLINKED_FILE_SUFFIX);
+ if ((strstr(path, MEMFD_PATH_PREFIX) != path) || !name_end)
return ERR_PTR(-EINVAL);
/*
