From 68ee0f704cb81e9ad0a78c644a83e1e9cd2ee578 Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date: Tue, 21 Jan 2025 16:11:06 -0500
Subject: [PATCH 1/1] Fix underallocation of abort_msg_s struct (CVE-2025-0395)

Include the space needed to store the length of the message itself, in
addition to the message string.  This resolves BZ #32582.

Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
---
 assert/assert.c            | 4 +++-
 sysdeps/posix/libc_fatal.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

Index: glibc-2.31/assert/assert.c
===================================================================
--- glibc-2.31.orig/assert/assert.c
+++ glibc-2.31/assert/assert.c
@@ -18,6 +18,7 @@
 #include <assert.h>
 #include <atomic.h>
 #include <ldsodefs.h>
+#include <libc-pointer-arith.h>
 #include <libintl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -64,7 +65,8 @@ __assert_fail_base (const char *fmt, con
       (void) __fxprintf (NULL, "%s", str);
       (void) fflush (stderr);
 
-      total = (total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1);
+      total = ALIGN_UP (total + sizeof (struct abort_msg_s) + 1,
+			GLRO(dl_pagesize));
       struct abort_msg_s *buf = __mmap (NULL, total, PROT_READ | PROT_WRITE,
 					MAP_ANON | MAP_PRIVATE, -1, 0);
       if (__glibc_likely (buf != MAP_FAILED))
Index: glibc-2.31/sysdeps/posix/libc_fatal.c
===================================================================
--- glibc-2.31.orig/sysdeps/posix/libc_fatal.c
+++ glibc-2.31/sysdeps/posix/libc_fatal.c
@@ -20,6 +20,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <ldsodefs.h>
+#include <libc-pointer-arith.h>
 #include <paths.h>
 #include <stdarg.h>
 #include <stdbool.h>
@@ -125,8 +126,8 @@ __libc_message (enum __libc_message_acti
 
       if ((action & do_abort))
 	{
-	  total = ((total + 1 + GLRO(dl_pagesize) - 1)
-		   & ~(GLRO(dl_pagesize) - 1));
+	  total = ALIGN_UP (total + sizeof (struct abort_msg_s) + 1,
+		   GLRO(dl_pagesize));
 	  struct abort_msg_s *buf = __mmap (NULL, total,
 					    PROT_READ | PROT_WRITE,
 					    MAP_ANON | MAP_PRIVATE, -1, 0);