From a8e9a5e73b391ece34df40e89ebe9dfc76370d50 Mon Sep 17 00:00:00 2001
From: Jeremy Soller <jackpot51@gmail.com>
Date: Thu, 19 Feb 2026 13:23:35 -0700
Subject: [PATCH] ipcd: use first segment size for limits of mmap

---
 ipcd/src/shm.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/ipcd/src/shm.rs b/ipcd/src/shm.rs
index 82c94fc9ed..0e80ddcf72 100644
--- a/ipcd/src/shm.rs
+++ b/ipcd/src/shm.rs
@@ -217,11 +217,12 @@ impl SchemeSync for ShmScheme {
             .buffer
         {
             Some(ref mut buf) => {
-                if total_size > buf.len() {
+                // TODO: This will not work well if there's multiple segments!
+                let segment = buf.segments.first().ok_or_else(|| Error::new(ERANGE))?;
+                if total_size > segment.size {
                     return Err(Error::new(ERANGE));
                 }
-                /// TODO: This will not work well if there's multiple segments!
-                Ok(buf.as_ptr() + offset as usize)
+                Ok(segment.base + offset as usize)
             }
             //TODO: this should be only handled by ftruncate
             ref mut buf @ None => {