Merge tag 'erofs-for-6.16-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:

 - Use the mounter’s credentials for file-backed mounts to resolve
   Android SELinux permission issues

 - Remove the unused trace event `erofs_destroy_inode`

 - Error out on crafted out-of-file-range encoded extents

 - Remove an incorrect check for encoded extents

* tag 'erofs-for-6.16-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: remove a superfluous check for encoded extents
  erofs: refuse crafted out-of-file-range encoded extents
  erofs: remove unused trace event erofs_destroy_inode
  erofs: impersonate the opener's credentials when accessing backing file

Author: torvalds

fs/erofs/fileio.c

@@ -47,6 +47,7 @@ static void erofs_fileio_ki_complete(struct kiocb *iocb, long ret)
 
 static void erofs_fileio_rq_submit(struct erofs_fileio_rq *rq)
 {
+	const struct cred *old_cred;
 	struct iov_iter iter;
 	int ret;
 
@@ -60,7 +61,9 @@ static void erofs_fileio_rq_submit(struct erofs_fileio_rq *rq)
 		rq->iocb.ki_flags = IOCB_DIRECT;
 	iov_iter_bvec(&iter, ITER_DEST, rq->bvecs, rq->bio.bi_vcnt,
 		      rq->bio.bi_iter.bi_size);
+	old_cred = override_creds(rq->iocb.ki_filp->f_cred);
 	ret = vfs_iocb_iter_read(rq->iocb.ki_filp, &rq->iocb, &iter);
+	revert_creds(old_cred);
 	if (ret != -EIOCBQUEUED)
 		erofs_fileio_ki_complete(&rq->iocb, ret);
 }

fs/erofs/zmap.c

@@ -597,6 +597,10 @@ static int z_erofs_map_blocks_ext(struct inode *inode,
 
 			if (la > map->m_la) {
 				r = mid;
+				if (la > lend) {
+					DBG_BUGON(1);
+					return -EFSCORRUPTED;
+				}
 				lend = la;
 			} else {
 				l = mid + 1;
@@ -635,12 +639,6 @@ static int z_erofs_map_blocks_ext(struct inode *inode,
 		}
 	}
 	map->m_llen = lend - map->m_la;
-	if (!last && map->m_llen < sb->s_blocksize) {
-		erofs_err(sb, "extent too small %llu @ offset %llu of nid %llu",
-			  map->m_llen, map->m_la, vi->nid);
-		DBG_BUGON(1);
-		return -EFSCORRUPTED;
-	}
 	return 0;
 }
 

include/trace/events/erofs.h

@@ -211,24 +211,6 @@ TRACE_EVENT(erofs_map_blocks_exit,
 		  show_mflags(__entry->mflags), __entry->ret)
 );
 
-TRACE_EVENT(erofs_destroy_inode,
-	TP_PROTO(struct inode *inode),
-
-	TP_ARGS(inode),
-
-	TP_STRUCT__entry(
-		__field(	dev_t,		dev		)
-		__field(	erofs_nid_t,	nid		)
-	),
-
-	TP_fast_assign(
-		__entry->dev	= inode->i_sb->s_dev;
-		__entry->nid	= EROFS_I(inode)->nid;
-	),
-
-	TP_printk("dev = (%d,%d), nid = %llu", show_dev_nid(__entry))
-);
-
 #endif /* _TRACE_EROFS_H */
 
  /* This part must be outside protection */