[xen stable-4.16] libfsimage/xfs: Add compile-time check to libfsimage

[patchbot@xxxxxxx]

commit 766126159ee963cdc16ba9cb2b0ca54b98bc148f
Author:     Alejandro Vallejo <alejandro.vallejo@xxxxxxxxx>
AuthorDate: Thu Sep 14 13:22:53 2023 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Sep 27 16:29:50 2023 +0100

    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@xxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    (cherry picked from commit 7d85c70431593550e32022e3a19a37f306f49e00)
---
 tools/libfsimage/Rules.mk       | 2 +-
 tools/libfsimage/xfs/fsys_xfs.c | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/libfsimage/Rules.mk b/tools/libfsimage/Rules.mk
index bb6d42abb4..80598fb70a 100644
--- a/tools/libfsimage/Rules.mk
+++ b/tools/libfsimage/Rules.mk
@@ -1,6 +1,6 @@
 include $(XEN_ROOT)/tools/Rules.mk
 
-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 += -Werror -D_GNU_SOURCE
 LDFLAGS += -L../common/
 
diff --git a/tools/libfsimage/xfs/fsys_xfs.c b/tools/libfsimage/xfs/fsys_xfs.c
index e4eb7e1ee2..4a8dd6f239 100644
--- a/tools/libfsimage/xfs/fsys_xfs.c
+++ b/tools/libfsimage/xfs/fsys_xfs.c
@@ -19,6 +19,7 @@
 
 #include <stdbool.h>
 #include <xenfsimage_grub.h>
+#include <xen-tools/libs.h>
 #include "xfs.h"
 
 #define MAX_LINK_COUNT 8
@@ -477,9 +478,10 @@ 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;
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16