From 332ae13af5d28cd46859a145c3b7353b9fa79321 Mon Sep 17 00:00:00 2001
From: Alex Lyon <arcterus@mail.com>
Date: Thu, 8 Mar 2018 17:06:09 -0800
Subject: [PATCH] string: fix out of bounds bug in strncmp
---
src/string/src/lib.rs | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/src/string/src/lib.rs b/src/string/src/lib.rs
index 8252dbf6..c272d921 100644
--- a/src/string/src/lib.rs
+++ b/src/string/src/lib.rs
@@ -159,14 +159,22 @@ pub unsafe extern "C" fn strncmp(s1: *const c_char, s2: *const c_char, n: usize)
let s1 = platform::c_str_n(s1, n);
let s2 = platform::c_str_n(s2, n);
- for i in 0..n {
+ let min_len = n.min(s1.len()).min(s2.len());
+ for i in 0..min_len {
let val = s1[i] - s2[i];
- if val != 0 || s1[i] == 0 {
+ if val != 0 {
return val as c_int;
}
}
- 0
+ // we can't just check for the NUL byte in the loop as c_str_n() removes it
+ if s1.len() > s2.len() {
+ s1[min_len] as c_int
+ } else if s1.len() < s2.len() {
+ -(s2[min_len] as c_int)
+ } else {
+ 0
+ }
}
#[no_mangle]
--
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