Commit 3be5cc23 authored Mar 15, 2016 by Markus Armbruster

target-ppc: Document TOCTTOU in hugepage support

The code to find the minimum page size is is vulnerable to TOCTTOU.
Added in commit 2d103aae "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>

parent 6741d38a

target-ppc/kvm.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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;