From 371baf5c9750a258fee21d0cb8c8d683bb057429 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 10 Jul 2023 09:02:33 -0700 Subject: [PATCH] xfs: convert flex-array declarations in struct xfs_attrlist* As of 6.5-rc1, UBSAN trips over the attrlist ioctl definitions using an array length of 1 to pretend to be a flex array. Kernel compilers have to support unbounded array declarations, so let's correct this. This may cause friction with userspace header declarations, but suck is life. ================================================================================ UBSAN: array-index-out-of-bounds in fs/xfs/xfs_ioctl.c:345:18 index 1 is out of range for type '__s32 [1]' Call Trace: dump_stack_lvl+0x33/0x50 __ubsan_handle_out_of_bounds+0x9c/0xd0 xfs_ioc_attr_put_listent+0x413/0x420 [xfs 4a986a89a77bb77402ab8a87a37da369ef6a3f09] xfs_attr_list_ilocked+0x170/0x850 [xfs 4a986a89a77bb77402ab8a87a37da369ef6a3f09] xfs_attr_list+0xb7/0x120 [xfs 4a986a89a77bb77402ab8a87a37da369ef6a3f09] xfs_ioc_attr_list+0x13b/0x2e0 [xfs 4a986a89a77bb77402ab8a87a37da369ef6a3f09] xfs_attrlist_by_handle+0xab/0x120 [xfs 4a986a89a77bb77402ab8a87a37da369ef6a3f09] xfs_file_ioctl+0x1ff/0x15e0 [xfs 4a986a89a77bb77402ab8a87a37da369ef6a3f09] vfs_ioctl+0x1f/0x60 The kernel and xfsprogs code that uses these structures will not have problems, but the long tail of external user programs might. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Kees Cook --- fs/xfs/libxfs/xfs_fs.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h index 9c60ebb..2cbf9ea 100644 --- a/fs/xfs/libxfs/xfs_fs.h +++ b/fs/xfs/libxfs/xfs_fs.h @@ -592,12 +592,12 @@ typedef struct xfs_attrlist_cursor { struct xfs_attrlist { __s32 al_count; /* number of entries in attrlist */ __s32 al_more; /* T/F: more attrs (do call again) */ - __s32 al_offset[1]; /* byte offsets of attrs [var-sized] */ + __s32 al_offset[]; /* byte offsets of attrs [var-sized] */ }; struct xfs_attrlist_ent { /* data from attr_list() */ __u32 a_valuelen; /* number bytes in value of attr */ - char a_name[1]; /* attr name (NULL terminated) */ + char a_name[]; /* attr name (NULL terminated) */ }; typedef struct xfs_fsop_attrlist_handlereq { -- 2.7.4