The code to find the minimum page size is is vulnerable to TOCTTOU.
Added in commit 2d103aa "target-ppc: fix hugepage support when using
memory-backend-file" (v2.4.0). Since I can't fix it myself right now,
add a FIXME comment.
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Michael Roth <mdr...@linux.vnet.ibm.com>
Signed-off-by: Markus Armbruster <arm...@redhat.com>
---
target-ppc/kvm.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index d67c169..0ef6ecd 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -333,6 +333,12 @@ static long gethugepagesize(const char *mem_path)
return fs.f_bsize;
}
+/*
+ * FIXME TOCTTOU: this iterates over memory backends' mem-path, which
+ * may or may not name the same files / on the same filesystem now as
+ * when we actually open and map them. Iterate over the file
+ * descriptors instead, and use qemu_fd_getpagesize().
+ */
static int find_max_supported_pagesize(Object *obj, void *opaque)
{
char *mem_path;
--
2.4.3
