linux-kernel - [PATCH] fs: heap/bss calculation ignore special section.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 9 Jun 2015 15:32:19 +0300
From:	Noam Camus <noamc@...hip.com>
To:	<linux-fsdevel@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:	<vgupta@...opsys.com>, <giladb@...hip.com>, <cmetcalf@...hip.com>,
	"Noam Camus" <noamc@...hip.com>
Subject: [PATCH] fs: heap/bss calculation ignore special section.

From: Noam Camus <noamc@...hip.com>

Today bss/heap is placed above last loaded sections.
However if STACK_TOP is not equal to TASK_SIZE we wish to ignore
such sections mapped to this gap between STACK_TOP and TASK_SIZE.
set_brk will never work for such case.

So at the moment this addition is just a sanity check.

An alternative (more complex):
Linux would make use of LMA field in ELF, then we can set VMA below
STACK_TOP and set LMA to be between STACK_TOP and TASK_SIZE to match
such special memory mapping.

Signed-off-by: Noam Camus <noamc@...hip.com>
---
 fs/binfmt_elf.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 241ef68..09f9483 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -962,6 +962,9 @@ static int load_elf_binary(struct linux_binprm *bprm)
 
 		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
 
+		if (k >= STACK_TOP)
+			continue;
+
 		if (k > elf_bss)
 			elf_bss = k;
 		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/