Check that we don't run off the end of the inline data buffer when we're
trying to read directory entries. xfs/348 triggered kernel memory being
exposed to userspace and a related complaint from the usercopy code.
Evidently once we call dir_emit, the VFS ignores error return values
since it's already begun copying data back to userspace.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_dir2_readdir.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index 003a99b..70bdd21 100644
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -69,6 +69,7 @@ xfs_dir2_sf_getdents(
xfs_dir2_dataptr_t dotdot_offset;
xfs_ino_t ino;
struct xfs_da_geometry *geo = args->geo;
+ char *endp;
ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
/*
@@ -83,6 +84,7 @@ xfs_dir2_sf_getdents(
ASSERT(dp->i_df.if_u1.if_data != NULL);
sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
+ endp = dp->i_df.if_u1.if_data + dp->i_df.if_bytes;
if (dp->i_d.di_size < xfs_dir2_sf_hdr_size(sfp->i8count))
return -EFSCORRUPTED;
@@ -130,6 +132,12 @@ xfs_dir2_sf_getdents(
for (i = 0; i < sfp->count; i++) {
__uint8_t filetype;
+ /* If we pass the end of the buffer, we're done. */
+ if (((char *)sfep + sizeof(*sfep)) >= endp ||
+ (char *)dp->d_ops->sf_nextentry(sfp, sfep) > endp) {
+ break;
+ }
+
off = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,
xfs_dir2_sf_get_offset(sfep));
--
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