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xfs: Fix bulkstat compat ioctls on x32 userspace.

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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: Nick Bowler <nbowler@draconx.ca>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Nick Bowler 2018-12-17 09:35:27 -08:00 committed by Darrick J. Wong
parent c456d64449
commit 7ca860e3c1
1 changed files with 30 additions and 4 deletions
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34
fs/xfs/xfs_ioctl32.c
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@ -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;