From: Jiri Kosina Date: Fri, 6 Jun 2008 05:46:05 +0000 (-0700) Subject: brk: make sys_brk() honor COMPAT_BRK when computing lower bound X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=a5b4592cf77b973c29e7c9695873a26052b58951;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git brk: make sys_brk() honor COMPAT_BRK when computing lower bound Fix a regression introduced by commit 4cc6028d4040f95cdb590a87db478b42b8be0508 Author: Jiri Kosina 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 Tested-by: Geert Uytterhoeven Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/mmap.c b/mm/mmap.c index 669499e7c2f5..3354fdd83d4b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -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; /*