Commit 7ca860e3 authored by Nick Bowler's avatar Nick Bowler Committed by Darrick J. Wong
Browse files

xfs: Fix bulkstat compat ioctls on x32 userspace. 



The bulkstat family of ioctls are problematic on x32, because there is
a mixup of native 32-bit and 64-bit conventions.  The xfs_fsop_bulkreq
struct contains pointers and 32-bit integers so that matches the native
32-bit layout, and that means the ioctl implementation goes into the
regular compat path on x32.

However, the 'ubuffer' member of that struct in turn refers to either
struct xfs_inogrp or xfs_bstat (or an array of these).  On x32, those
structures match the native 64-bit layout.  The compat implementation
writes out the 32-bit version of these structures.  This is not the
expected format for x32 userspace, causing problems.

Fortunately the functions which actually output these xfs_inogrp and
xfs_bstat structures have an easy way to select which output format
is required, so we just need a little tweak to select the right format
on x32.

Signed-off-by: default avatarNick Bowler <nbowler@draconx.ca>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent c456d644

fs/xfs/xfs_ioctl32.c

+30 −4
Original line number Diff line number Diff line
@@ -241,6 +241,32 @@ xfs_compat_ioc_bulkstat( 
	int			done;

	int			error;



	/*

	 * Output structure handling functions.  Depending on the command,

	 * either the xfs_bstat and xfs_inogrp structures are written out

	 * to userpace memory via bulkreq.ubuffer.  Normally the compat

	 * functions and structure size are the correct ones to use ...

	 */

	inumbers_fmt_pf inumbers_func = xfs_inumbers_fmt_compat;

	bulkstat_one_pf	bs_one_func = xfs_bulkstat_one_compat;

	size_t bs_one_size = sizeof(struct compat_xfs_bstat);



#ifdef CONFIG_X86_X32

	if (in_x32_syscall()) {

		/*

		 * ... but on x32 the input xfs_fsop_bulkreq has pointers

		 * which must be handled in the "compat" (32-bit) way, while

		 * the xfs_bstat and xfs_inogrp structures follow native 64-

		 * bit layout convention.  So adjust accordingly, otherwise

		 * the data written out in compat layout will not match what

		 * x32 userspace expects.

		 */

		inumbers_func = xfs_inumbers_fmt;

		bs_one_func = xfs_bulkstat_one;

		bs_one_size = sizeof(struct xfs_bstat);

	}

#endif



	/* done = 1 if there are more stats to get and if bulkstat */

	/* should be called again (unused here, but used in dmapi) */
@@ -272,15 +298,15 @@ xfs_compat_ioc_bulkstat( 


	if (cmd == XFS_IOC_FSINUMBERS_32) {

		error = xfs_inumbers(mp, &inlast, &count,

				bulkreq.ubuffer, xfs_inumbers_fmt_compat);

				bulkreq.ubuffer, inumbers_func);

	} else if (cmd == XFS_IOC_FSBULKSTAT_SINGLE_32) {

		int res;



		error = xfs_bulkstat_one_compat(mp, inlast, bulkreq.ubuffer,

				sizeof(compat_xfs_bstat_t), NULL, &res);

		error = bs_one_func(mp, inlast, bulkreq.ubuffer,

				bs_one_size, NULL, &res);

	} else if (cmd == XFS_IOC_FSBULKSTAT_32) {

		error = xfs_bulkstat(mp, &inlast, &count,

			xfs_bulkstat_one_compat, sizeof(compat_xfs_bstat_t),

			bs_one_func, bs_one_size,

			bulkreq.ubuffer, &done);

	} else

		error = -EINVAL;

CRA Git | Maintained and supported by SUSTech CRA and CCSE