Commit a5b4592c authored Jun 05, 2008 by Jiri Kosina Committed by Linus Torvalds Jun 06, 2008

brk: make sys_brk() honor COMPAT_BRK when computing lower bound



Fix a regression introduced by

commit 4cc6028d
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>

parent 33dda515

mm/mmap.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -245,10 +245,16 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
		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;

		/*

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