From 3593063f735f453d43f461292e26913436c11ca3 Mon Sep 17 00:00:00 2001
From: Alexander Kanavin <alex.kanavin@gmail.com>
Date: Sat, 1 May 2021 13:06:12 +0200
Subject: [PATCH] lib/ext2fs/unix_io.c: revert parts of "libext2fs: fix
 potential races in unix_io"

Upstream-Status: Submitted [https://github.com/tytso/e2fsprogs/pull/68]
Signed-off-by: Alexander Kanavin <alex.kanavin@gmail.com>
---
 lib/ext2fs/unix_io.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/lib/ext2fs/unix_io.c b/lib/ext2fs/unix_io.c
index 528c2fbc..f4916b21 100644
--- a/lib/ext2fs/unix_io.c
+++ b/lib/ext2fs/unix_io.c
@@ -311,10 +311,10 @@ bounce_read:
 			size += really_read;
 			goto short_read;
 		}
-		actual = size;
-		if (actual > align_size)
-			actual = align_size;
-		actual -= offset;
+		if ((actual + offset) > align_size)
+			actual = align_size - offset;
+		if (actual > size)
+			actual = size;
 		memcpy(buf, data->bounce + offset, actual);
 
 		really_read += actual;
@@ -455,9 +455,10 @@ bounce_write:
 			}
 		}
 		actual = size;
-		if (actual > align_size)
-			actual = align_size;
-		actual -= offset;
+		if ((actual + offset) > align_size)
+			actual = align_size - offset;
+		if (actual > size)
+			actual = size;
 		memcpy(((char *)data->bounce) + offset, buf, actual);
 		if (ext2fs_llseek(data->dev, aligned_blk * align_size, SEEK_SET) < 0) {
 			retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
-- 
2.24.0