From 59d7e2e82420c7b51846ca3e1037a62c2eb01161 Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh-github@glandium.org>
Date: Fri, 29 Jan 2021 18:38:43 +0900
Subject: [PATCH] elf: avoid overflow when header.n_namesz is 0 (#256)

---
 src/elf/note.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/elf/note.rs b/src/elf/note.rs
index 04977121..b325d1f4 100644
--- a/src/elf/note.rs
+++ b/src/elf/note.rs
@@ -205,8 +205,10 @@ if_alloc! {
             };
             debug!("{:?} - {:#x}", header, *offset);
             // -1 because includes \0 terminator
-            let name = bytes.gread_with::<&'a str>(offset, ctx::StrCtx::Length(header.n_namesz - 1))?;
-            *offset += 1;
+            let name = bytes.gread_with::<&'a str>(offset, ctx::StrCtx::Length(header.n_namesz.saturating_sub(1)))?;
+            if (header.n_namesz > 0) {
+                *offset += 1;
+            }
             align(alignment, offset);
             debug!("note name {} - {:#x}", name, *offset);
             let desc = bytes.gread_with::<&'a [u8]>(offset, header.n_descsz)?;