From: Julian Seward <jseward@acm.org>
Date: Mon, 14 Oct 2013 14:50:57 +0000 (+0000)
Subject: Disallow client mmap calls with MAP_32BIT as a flag.
X-Git-Tag: svn/VALGRIND_3_9_0~47
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4fc45578f6826163315c205fa15db7d6d85ac211;p=thirdparty%2Fvalgrind.git

Disallow client mmap calls with MAP_32BIT as a flag.
Fixes, or at least addresses, #324181.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13644
---

diff --git a/coregrind/m_syswrap/syswrap-generic.c b/coregrind/m_syswrap/syswrap-generic.c
index 34dad5abf9..0e0b3f6818 100644
--- a/coregrind/m_syswrap/syswrap-generic.c
+++ b/coregrind/m_syswrap/syswrap-generic.c
@@ -1996,7 +1996,7 @@ ML_(generic_PRE_sys_mmap) ( ThreadId tid,
    MapRequest mreq;
    Bool       mreq_ok;
 
-#if defined(VGO_darwin)
+#  if defined(VGO_darwin)
    // Nb: we can't use this on Darwin, it has races:
    // * needs to RETRY if advisory succeeds but map fails  
    //   (could have been some other thread in a nonblocking call)
@@ -2004,7 +2004,7 @@ ML_(generic_PRE_sys_mmap) ( ThreadId tid,
    //   (mmap will cheerfully smash whatever's already there, which might 
    //   be a new mapping from some other thread in a nonblocking call)
    VG_(core_panic)("can't use ML_(generic_PRE_sys_mmap) on Darwin");
-#endif
+#  endif
 
    if (arg2 == 0) {
       /* SuSV3 says: If len is zero, mmap() shall fail and no mapping
@@ -2027,6 +2027,15 @@ ML_(generic_PRE_sys_mmap) ( ThreadId tid,
       return VG_(mk_SysRes_Error)( VKI_EINVAL );
    }
 
+#  if defined(VKI_MAP_32BIT)
+   /* We can't support MAP_32BIT (at least, not without significant
+      complication), and it's royally unportable, so if the client
+      asks for it, just fail it. */
+   if (arg4 & VKI_MAP_32BIT) {
+      return VG_(mk_SysRes_Error)( VKI_ENOMEM );
+   }
+#  endif
+
    /* Figure out what kind of allocation constraints there are
       (fixed/hint/any), and ask aspacem what we should do. */
    mreq.start = arg1;
diff --git a/include/vki/vki-amd64-linux.h b/include/vki/vki-amd64-linux.h
index 4d97ec4cb4..77c49c9c03 100644
--- a/include/vki/vki-amd64-linux.h
+++ b/include/vki/vki-amd64-linux.h
@@ -236,6 +236,7 @@ struct vki_sigcontext {
 #define VKI_MAP_PRIVATE	0x02		/* Changes are private */
 #define VKI_MAP_FIXED	0x10		/* Interpret addr exactly */
 #define VKI_MAP_ANONYMOUS	0x20	/* don't use a file */
+#define VKI_MAP_32BIT	0x40		/* only give out 32bit addresses */
 #define VKI_MAP_NORESERVE       0x4000  /* don't check for reservations */
 
 //----------------------------------------------------------------------