From: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Date: Thu, 14 Sep 2023 12:22:53 +0000 (+0100)
Subject: libfsimage/xfs: Add compile-time check to libfsimage
X-Git-Tag: 4.18.0-rc3~11
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=7d85c70431593550e32022e3a19a37f306f49e00;p=xen.git

libfsimage/xfs: Add compile-time check to libfsimage

Adds the common tools include folder to the -I compile flags
of libfsimage. This allows us to use:
  xen-tools/common-macros.h:BUILD_BUG_ON()

With it, statically assert a sanitized "blocklog - SECTOR_BITS" cannot
underflow.

This is part of XSA-443 / CVE-2023-34325

Signed-off-by: Alejandro Vallejo <alejandro.vallejo@cloud.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---

diff --git a/tools/libfsimage/common.mk b/tools/libfsimage/common.mk
index 4fc8c66795..e4336837d0 100644
--- a/tools/libfsimage/common.mk
+++ b/tools/libfsimage/common.mk
@@ -1,7 +1,7 @@
 include $(XEN_ROOT)/tools/Rules.mk
 
 FSDIR := $(libdir)/xenfsimage
-CFLAGS += -Wno-unknown-pragmas -I$(XEN_ROOT)/tools/libfsimage/common/ -DFSIMAGE_FSDIR=\"$(FSDIR)\"
+CFLAGS += -Wno-unknown-pragmas -I$(XEN_ROOT)/tools/libfsimage/common/ $(CFLAGS_xeninclude) -DFSIMAGE_FSDIR=\"$(FSDIR)\"
 CFLAGS += -D_GNU_SOURCE
 LDFLAGS += -L../common/
 
diff --git a/tools/libfsimage/xfs/fsys_xfs.c b/tools/libfsimage/xfs/fsys_xfs.c
index b5c53d3d22..e98b367901 100644
--- a/tools/libfsimage/xfs/fsys_xfs.c
+++ b/tools/libfsimage/xfs/fsys_xfs.c
@@ -20,6 +20,7 @@
 #include <stddef.h>
 #include <stdbool.h>
 #include <xenfsimage_grub.h>
+#include <xen-tools/common-macros.h>
 #include "xfs.h"
 
 #define MAX_LINK_COUNT	8
@@ -475,9 +476,10 @@ xfs_mount (fsi_file_t *ffi, const char *options)
 	xfs.agblklog = super.sb_agblklog;
 
 	/* Derived from sanitized parameters */
+	BUILD_BUG_ON(XFS_SB_BLOCKLOG_MIN < SECTOR_BITS);
+	xfs.bdlog = super.sb_blocklog - SECTOR_BITS;
 	xfs.bsize = 1 << super.sb_blocklog;
 	xfs.blklog = super.sb_blocklog;
-	xfs.bdlog = super.sb_blocklog - SECTOR_BITS;
 	xfs.isize = 1 << super.sb_inodelog;
 	xfs.dirbsize = 1 << (super.sb_blocklog + super.sb_dirblklog);
 	xfs.inopblog = super.sb_blocklog - super.sb_inodelog;