From 295bef07d6bd18cd58746e46b400faadfb54b712 Mon Sep 17 00:00:00 2001
From: Corinna Vinschen <corinna@vinschen.de>
Date: Tue, 5 Dec 2023 22:08:01 +0100
Subject: Cygwin: posix_fallocate(3): fix offset and length sanity check

- len must not be <= 0
- offset + len must not exceed off_t (max. file size)

Fixes: 7636b5859062 ("* autoload.cc (NtSetInformationFile): Define.")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
---
 winsup/cygwin/syscalls.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'winsup')

diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index b73391d8f..3edb55bc6 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -3030,8 +3030,10 @@ extern "C" int
 posix_fallocate (int fd, off_t offset, off_t len)
 {
   int res = 0;
-  if (offset < 0 || len == 0)
+  if (offset < 0 || len <= 0)
     res = EINVAL;
+  else if (INT64_MAX - len < offset)
+    res = EFBIG;
   else
     {
       cygheap_fdget cfd (fd);
-- 
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