From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELsmtkaPHwMG5DqoAbIK3frQogYtyOxTWPO3B9e8KLpZe4WjwJdBVSv1GrPmWJVGacclHUtq ARC-Seal: i=1; a=rsa-sha256; t=1520356829; cv=none; d=google.com; s=arc-20160816; b=IEm6lO1BRmF9x9rSO4b+1qSW6MU+kYit9QT6v8L0jhh+OSezp7DAbJ/X45XbOzKH2o TdqNIUnAKkBV3R9zbBpmGscm62y2eTDY1l6fvlyDYjfe3z5b1u5OpLwVNjisb1+orkk2 jmDOu3X5mkeBD2pmYz5ZmI00rmbPTsAM8wF7DaVcBDefoGr+DunkdkbmrxaG8ebaYVRG SPK0Uw8c0lqQ7MZ3x8DYrhXFKA8k553VBWDnjhYp18cq+Ve5ajN+/0C4RsFY142C8VrN b/cnQ41bY7RQFibozdvjWFl+KqPK1mVD2zOYFcw8IK9u0qdZC9AAjPD93Fy9HuatuI/F LrrQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :dkim-signature:delivered-to:list-id:list-subscribe:list-unsubscribe :list-help:list-post:precedence:mailing-list :arc-authentication-results; bh=4ZownzUDtrY97MLskUPQVnSjwTn4V6B6F7ArBGM/nUM=; b=gU7BuLqMTpXICeRCdICAFaHR5zTJJhM1Xm/jLiPeSdZ9s8y3wVkP3pklA4KMLMZLWP rF1/gZCp1F1hXCewNYv/bDIgm9VCaF8qcJQENc4UKLAGxvaokDsG03EqiAbTjfOs0OPz tW2LxDaefEoY2OYfNDEVNCKfysZipXmRbLRDVNUnNcu44Y/cjGXwMf3/QyKMzsVP6ZX9 8r9BWdJIcYAPPHUAFPdLfZeCdX/GEpnUjqjub5YqXyaXxN+FN/5kXPBawWegKep7tjjn /9dRGX4CgBzlUDSDcsL38rHnLBhZ5sDUHLwlcyEjfmA6t28iBD+hSy2e/5ziTMH7SZ/1 Zq6w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=jTDB8pEL; spf=pass (google.com: domain of kernel-hardening-return-12154-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12154-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=jTDB8pEL; spf=pass (google.com: domain of kernel-hardening-return-12154-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12154-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Subject: Re: [PATCH 6/7] lkdtm: crash on overwriting protected pmalloc var To: Igor Stoppa , david@fromorbit.com, willy@infradead.org, keescook@chromium.org, mhocko@kernel.org Cc: labbott@redhat.com, linux-security-module@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com References: <20180228200620.30026-1-igor.stoppa@huawei.com> <20180228200620.30026-7-igor.stoppa@huawei.com> From: J Freyensee Message-ID: <1723ee8d-c89e-0704-c2c3-254eda39dc8b@gmail.com> Date: Tue, 6 Mar 2018 09:20:04 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180228200620.30026-7-igor.stoppa@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1593676876599291388?= X-GMAIL-MSGID: =?utf-8?q?1594209682165483415?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 2/28/18 12:06 PM, Igor Stoppa wrote: > Verify that pmalloc read-only protection is in place: trying to > overwrite a protected variable will crash the kernel. > > Signed-off-by: Igor Stoppa > --- > drivers/misc/lkdtm.h | 1 + > drivers/misc/lkdtm_core.c | 3 +++ > drivers/misc/lkdtm_perms.c | 28 ++++++++++++++++++++++++++++ > 3 files changed, 32 insertions(+) > > diff --git a/drivers/misc/lkdtm.h b/drivers/misc/lkdtm.h > index 9e513dcfd809..dcda3ae76ceb 100644 > --- a/drivers/misc/lkdtm.h > +++ b/drivers/misc/lkdtm.h > @@ -38,6 +38,7 @@ void lkdtm_READ_BUDDY_AFTER_FREE(void); > void __init lkdtm_perms_init(void); > void lkdtm_WRITE_RO(void); > void lkdtm_WRITE_RO_AFTER_INIT(void); > +void lkdtm_WRITE_RO_PMALLOC(void); Does this need some sort of #ifdef too? > void lkdtm_WRITE_KERN(void); > void lkdtm_EXEC_DATA(void); > void lkdtm_EXEC_STACK(void); > diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c > index 2154d1bfd18b..c9fd42bda6ee 100644 > --- a/drivers/misc/lkdtm_core.c > +++ b/drivers/misc/lkdtm_core.c > @@ -155,6 +155,9 @@ static const struct crashtype crashtypes[] = { > CRASHTYPE(ACCESS_USERSPACE), > CRASHTYPE(WRITE_RO), > CRASHTYPE(WRITE_RO_AFTER_INIT), > +#ifdef CONFIG_PROTECTABLE_MEMORY > + CRASHTYPE(WRITE_RO_PMALLOC), > +#endif > CRASHTYPE(WRITE_KERN), > CRASHTYPE(REFCOUNT_INC_OVERFLOW), > CRASHTYPE(REFCOUNT_ADD_OVERFLOW), > diff --git a/drivers/misc/lkdtm_perms.c b/drivers/misc/lkdtm_perms.c > index 53b85c9d16b8..0ac9023fd2b0 100644 > --- a/drivers/misc/lkdtm_perms.c > +++ b/drivers/misc/lkdtm_perms.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > #include > > /* Whether or not to fill the target memory area with do_nothing(). */ > @@ -104,6 +105,33 @@ void lkdtm_WRITE_RO_AFTER_INIT(void) > *ptr ^= 0xabcd1234; > } > > +#ifdef CONFIG_PROTECTABLE_MEMORY > +void lkdtm_WRITE_RO_PMALLOC(void) > +{ > + struct gen_pool *pool; > + int *i; > + > + pool = pmalloc_create_pool("pool", 0); > + if (unlikely(!pool)) { > + pr_info("Failed preparing pool for pmalloc test."); > + return; > + } > + > + i = (int *)pmalloc(pool, sizeof(int), GFP_KERNEL); > + if (unlikely(!i)) { > + pr_info("Failed allocating memory for pmalloc test."); > + pmalloc_destroy_pool(pool); > + return; > + } > + > + *i = INT_MAX; > + pmalloc_protect_pool(pool); > + > + pr_info("attempting bad pmalloc write at %p\n", i); > + *i = 0; OK, now I'm on the right version of this patch series, same comment applies.  I don't get the local *i assignment at the end of the function, but seems harmless. Except the two minor comments, otherwise, Reviewed-by: Jay Freyensee > +} > +#endif > + > void lkdtm_WRITE_KERN(void) > { > size_t size;