lkml.org 
[lkml]   [2008]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[patch 44/50] brk: make sys_brk() honor COMPAT_BRK when computing lower bound
-stable review patch.  If anyone has any objections, please let us know.
---------------------

From: Jiri Kosina <jkosina@suse.cz>

upstream commit: a5b4592cf77b973c29e7c9695873a26052b58951

Fix a regression introduced by

commit 4cc6028d4040f95cdb590a87db478b42b8be0508
Author: Jiri Kosina <jkosina@suse.cz>
Date: Wed Feb 6 22:39:44 2008 +0100

brk: check the lower bound properly

The check in sys_brk() on minimum value the brk might have must take
CONFIG_COMPAT_BRK setting into account. When this option is turned on
(i.e. we support ancient legacy binaries, e.g. libc5-linked stuff), the
lower bound on brk value is mm->end_code, otherwise the brk start is
allowed to be arbitrarily shifted.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
mm/mmap.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -242,10 +242,16 @@ asmlinkage unsigned long sys_brk(unsigne
unsigned long rlim, retval;
unsigned long newbrk, oldbrk;
struct mm_struct *mm = current->mm;
+ unsigned long min_brk;

down_write(&mm->mmap_sem);

- if (brk < mm->start_brk)
+#ifdef CONFIG_COMPAT_BRK
+ min_brk = mm->end_code;
+#else
+ min_brk = mm->start_brk;
+#endif
+ if (brk < min_brk)
goto out;

/*
--


\
 
 \ /
  Last update: 2008-06-07 03:27    [W:0.218 / U:0.252 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site