File 0191-9pfs-fix-O_PATH-build-break-with-ol.patch of Package qemu-linux-user.12243

Overview Repositories Revisions Requests Users Attributes Meta

File 0191-9pfs-fix-O_PATH-build-break-with-ol.patch of Package qemu-linux-user.12243

From 84658d57948c4feb904d6ff0a7c016b6ce4b1c4d Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Mon, 6 Mar 2017 17:34:01 +0100
Subject: [PATCH] 9pfs: fix O_PATH build break with older glibc versions

When O_PATH is used with O_DIRECTORY, it only acts as an optimization: the
openat() syscall simply finds the name in the VFS, and doesn't trigger the
underlying filesystem.

On systems that don't define O_PATH, because they have glibc version 2.13
or older for example, we can safely omit it. We don't want to deactivate
O_PATH globally though, in case it is used without O_DIRECTORY. The is done
with a dedicated macro.

Systems without O_PATH may thus fail to resolve names that involve
unreadable directories, compared to newer systems succeeding, but such
corner case failure is our only option on those older systems to avoid
the security hole of chasing symlinks inappropriately.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
(added last paragraph to changelog as suggested by Eric Blake)
Signed-off-by: Greg Kurz <groug@kaod.org>

(cherry picked from commit 918112c02aff2bac4cb72dc2feba0cb05305813e)
[BR: Fix and/or infrastructure for BSC#1020427 CVE-2016-9602]
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
 hw/9pfs/9p-util.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index 091f3ce88e..cb7b2072d3 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -22,7 +22,12 @@ static inline void close_preserve_errno(int fd)
 
 static inline int openat_dir(int dirfd, const char *name)
 {
-    return openat(dirfd, name, O_DIRECTORY | O_RDONLY | O_PATH);
+#ifdef O_PATH
+#define OPENAT_DIR_O_PATH O_PATH
+#else
+#define OPENAT_DIR_O_PATH 0
+#endif
+    return openat(dirfd, name, O_DIRECTORY | O_RDONLY | OPENAT_DIR_O_PATH);
 }
 
 static inline int openat_file(int dirfd, const char *name, int flags,

Places

File 0191-9pfs-fix-O_PATH-build-break-with-ol.patch of Package qemu-linux-user.12243

Places