[PATCH] fs: sync_file_range: avoid overflowing signed calculation

[Sasha Levin]

When calculating the end byte for the sync we preform an addition which might
result in an overflow, which is undefined. Avoid it by doing unsigned
addition.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
 fs/sync.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/sync.c b/fs/sync.c
index 6ccfc38..f9cb38f 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -286,7 +286,7 @@ SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
 	if (flags & ~VALID_FLAGS)
 		goto out;
 
-	endbyte = offset + nbytes;
+	endbyte = offset + (u64)nbytes;
 
 	if ((s64)offset < 0)
 		goto out;
-- 
1.7.10.4

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