From 99c20c07ab7685744acc91076e3f474b7d95f67c Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Mon, 2 Jan 2023 00:58:03 +0100
Subject: boot: Fix erroneous munmap in S_io_read on error

---
 boot/boot.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'boot/boot.c')

diff --git a/boot/boot.c b/boot/boot.c
index eb78a1c6..978d8943 100644
--- a/boot/boot.c
+++ b/boot/boot.c
@@ -1458,10 +1458,11 @@ S_io_read (mach_port_t object,
   ioctl (0, FIONREAD, &avail);
   if (avail)
     {
+      data_t orig_data = *data;
       if (amount > *datalen)
 	*data = mmap (0, amount, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
       *datalen = read (0, *data, amount);
-      if (*datalen == -1)
+      if (*datalen == -1 && *data != orig_data)
 	munmap (*data, amount);
       unlock_readlock ();
       return *datalen == -1 ? errno : 0;
-- 
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