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[Qemu-devel] [PATCH v2 03/42] target-ppc: Document TOCTTOU in hugepage s
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PATCH v2 03/42] target-ppc: Document TOCTTOU in hugepage support |
Date: |
Mon, 7 Mar 2016 20:25:15 +0100 |
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 <address@hidden>
Cc: Michael Roth <address@hidden>
Signed-off-by: Markus Armbruster <address@hidden>
---
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
- [Qemu-devel] [PATCH v2 14/42] ivshmem: Compile debug prints unconditionally to prevent bit-rot, (continued)
- [Qemu-devel] [PATCH v2 21/42] ivshmem: Clean up MSI-X conditions, Markus Armbruster, 2016/03/07
- [Qemu-devel] [PATCH v2 03/42] target-ppc: Document TOCTTOU in hugepage support,
Markus Armbruster <=
- [Qemu-devel] [PATCH v2 06/42] qemu-doc: Fix ivshmem huge page example, Markus Armbruster, 2016/03/07
- [Qemu-devel] [PATCH v2 35/42] ivshmem: Inline check_shm_size() into its only caller, Markus Armbruster, 2016/03/07
- [Qemu-devel] [PATCH v2 20/42] ivshmem: Clean up register callbacks, Markus Armbruster, 2016/03/07
- [Qemu-devel] [PATCH v2 05/42] ivshmem-server: Don't overload POSIX shmem and file name, Markus Armbruster, 2016/03/07