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
| ||
|
Message-ID: <7ddc633e-c724-ad8d-e7ca-62d6b012b9e9@redhat.com> Date: Fri, 29 Sep 2023 13:33:50 +0200 (CEST) From: Sebastian Ott <sebott@...hat.com> To: Kees Cook <keescook@...omium.org> cc: Eric Biederman <ebiederm@...ssion.com>, Thomas Weißschuh <linux@...ssschuh.net>, Pedro Falcato <pedro.falcato@...il.com>, Al Viro <viro@...iv.linux.org.uk>, Christian Brauner <brauner@...nel.org>, Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, linux-hardening@...r.kernel.org Subject: Re: [PATCH v4 0/6] binfmt_elf: Support segments with 0 filesz and misaligned starts Hello Kees, On Thu, 28 Sep 2023, Kees Cook wrote: > This is the continuation of the work Eric started for handling > "p_memsz > p_filesz" in arbitrary segments (rather than just the last, > BSS, segment). I've added the suggested changes: > > - drop unused "elf_bss" variable > - refactor load_elf_interp() to use elf_load() > - refactor load_elf_library() to use elf_load() > - report padzero() errors when PROT_WRITE is present > - drop vm_brk() While I was debugging the initial issue I stumbled over the following - care to take it as part of this series? ----->8 [PATCH] mm: vm_brk_flags don't bail out while holding lock Calling vm_brk_flags() with flags set other than VM_EXEC will exit the function without releasing the mmap_write_lock. Just do the sanity check before the lock is acquired. This doesn't fix an actual issue since no caller sets a flag other than VM_EXEC. Cc: Andrew Morton <akpm@...ux-foundation.org> Cc: linux-mm@...ck.org Signed-off-by: Sebastian Ott <sebott@...hat.com> --- mm/mmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index b56a7f0c9f85..7ed286662839 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3143,13 +3143,13 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) if (!len) return 0; - if (mmap_write_lock_killable(mm)) - return -EINTR; - /* Until we need other flags, refuse anything except VM_EXEC. */ if ((flags & (~VM_EXEC)) != 0) return -EINVAL; + if (mmap_write_lock_killable(mm)) + return -EINTR; + ret = check_brk_limits(addr, len); if (ret) goto limits_failed; -- 2.41.0
Powered by blists - more mailing lists