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authorNick Bowler <nbowler@draconx.ca>2018-12-17 20:35:27 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2018-12-18 21:55:20 +0300
commit7ca860e3c1a74ad6bd8949364073ef1044cad758 (patch)
tree1ca973be589423b562b186c0c3cb97e777d75df3
parentc456d64449efe37da50832b63d91652a85ea1d20 (diff)
downloadlinux-7ca860e3c1a74ad6bd8949364073ef1044cad758.tar.xz
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: Nick Bowler <nbowler@draconx.ca> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
-rw-r--r--fs/xfs/xfs_ioctl32.c34
1 files changed, 30 insertions, 4 deletions
diff --git a/fs/xfs/xfs_ioctl32.c b/fs/xfs/xfs_ioctl32.c
index 4c34efcbf7e8..b044f7d36782 100644
--- a/fs/xfs/xfs_ioctl32.c
+++ b/fs/xfs/xfs_ioctl32.c
@@ -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;