patch 8.0.0636: when reading the undo file fails may use uninitialized data
Problem: When reading the undo file fails may use uninitialized data.
Solution: Always clear the buffer on failure.
diff --git a/src/undo.c b/src/undo.c
index 82c66b6..aeca25f 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -1063,6 +1063,8 @@
static int
undo_read(bufinfo_T *bi, char_u *buffer, size_t size)
{
+ int retval = OK;
+
#ifdef FEAT_CRYPT
if (bi->bi_buffer != NULL)
{
@@ -1078,10 +1080,8 @@
n = fread(bi->bi_buffer, 1, (size_t)CRYPT_BUF_SIZE, bi->bi_fp);
if (n == 0)
{
- /* Error may be checked for only later. Fill with zeros,
- * so that the reader won't use garbage. */
- vim_memset(p, 0, size_todo);
- return FAIL;
+ retval = FAIL;
+ break;
}
bi->bi_avail = n;
bi->bi_used = 0;
@@ -1095,12 +1095,17 @@
size_todo -= (int)n;
p += n;
}
- return OK;
}
+ else
#endif
if (fread(buffer, (size_t)size, 1, bi->bi_fp) != 1)
- return FAIL;
- return OK;
+ retval = FAIL;
+
+ if (retval == FAIL)
+ /* Error may be checked for only later. Fill with zeros,
+ * so that the reader won't use garbage. */
+ vim_memset(buffer, 0, size);
+ return retval;
}
/*