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authorMarkus Armbruster <armbru@redhat.com>2016-03-15 19:34:16 +0100
committerMarkus Armbruster <armbru@redhat.com>2016-03-18 17:34:21 +0100
commit3be5cc23245637577210e43e68dd3babd01fbb5e (patch)
tree8db37cea025da470a7ca1a65256de7ba1531b382
parent6741d38ad0f2405a6e999ebc9550801b01aca479 (diff)
target-ppc: Document TOCTTOU in hugepage support
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 <pbonzini@redhat.com> Cc: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <1458066895-20632-2-git-send-email-armbru@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
-rw-r--r--target-ppc/kvm.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 776336b8b4..2fc993143e 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;