From 3cd9f3f6ab7d906e23d0ddc4bb0604b09966961f Mon Sep 17 00:00:00 2001
From: Marcin Mielniczuk <marmistrz.dev@zoho.eu>
Date: Tue, 6 Aug 2019 19:34:10 +0200
Subject: [PATCH 1/2] Add an overflow check in truncate implementation for
 Unix.

---
 src/libstd/fs.rs          |  2 ++
 src/libstd/sys/unix/fs.rs | 12 +++++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index f7c32a5c20d3d..5f76875bd66c4 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -468,6 +468,8 @@ impl File {
     /// # Errors
     ///
     /// This function will return an error if the file is not opened for writing.
+    /// Also, std::io::ErrorKind::InvalidInput will be returned if the desired
+    /// length would cause an overflow due to the implementation specifics.
     ///
     /// # Examples
     ///
diff --git a/src/libstd/sys/unix/fs.rs b/src/libstd/sys/unix/fs.rs
index cc1f0790d4334..48e449d9c377c 100644
--- a/src/libstd/sys/unix/fs.rs
+++ b/src/libstd/sys/unix/fs.rs
@@ -1,5 +1,6 @@
 use crate::os::unix::prelude::*;
 
+use crate::convert::TryInto;
 use crate::ffi::{CString, CStr, OsString, OsStr};
 use crate::fmt;
 use crate::io::{self, Error, ErrorKind, SeekFrom, IoSlice, IoSliceMut};
@@ -554,9 +555,14 @@ impl File {
         return crate::sys::android::ftruncate64(self.0.raw(), size);
 
         #[cfg(not(target_os = "android"))]
-        return cvt_r(|| unsafe {
-            ftruncate64(self.0.raw(), size as off64_t)
-        }).map(|_| ());
+        {
+            let size: off64_t = size
+                .try_into()
+                .map_err(|e| io::Error::new(io::ErrorKind::InvalidInput, e))?;
+            cvt_r(|| unsafe {
+                ftruncate64(self.0.raw(), size)
+            }).map(|_| ())
+        }
     }
 
     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {

From 3adbf63b119d26edf1997e974d0727791d6f4060 Mon Sep 17 00:00:00 2001
From: Marcin Mielniczuk <marmistrz.dev@zoho.eu>
Date: Thu, 8 Aug 2019 11:44:59 +0200
Subject: [PATCH 2/2] Move the TryInto import into the inner scope

---
 src/libstd/sys/unix/fs.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libstd/sys/unix/fs.rs b/src/libstd/sys/unix/fs.rs
index 48e449d9c377c..0223957e611fb 100644
--- a/src/libstd/sys/unix/fs.rs
+++ b/src/libstd/sys/unix/fs.rs
@@ -1,6 +1,5 @@
 use crate::os::unix::prelude::*;
 
-use crate::convert::TryInto;
 use crate::ffi::{CString, CStr, OsString, OsStr};
 use crate::fmt;
 use crate::io::{self, Error, ErrorKind, SeekFrom, IoSlice, IoSliceMut};
@@ -556,6 +555,7 @@ impl File {
 
         #[cfg(not(target_os = "android"))]
         {
+            use crate::convert::TryInto;
             let size: off64_t = size
                 .try_into()
                 .map_err(|e| io::Error::new(io::ErrorKind::InvalidInput, e))?;