From: David Laight <David.Laight@ACULAB.COM>
To: 'Salvatore Mesoraca' <s.mesoraca16@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "kernel-hardening@lists.openwall.com"
<kernel-hardening@lists.openwall.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-security-module@vger.kernel.org"
<linux-security-module@vger.kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Brad Spengler <spender@grsecurity.net>,
"Casey Schaufler" <casey@schaufler-ca.com>,
Christoph Hellwig <hch@infradead.org>,
James Morris <james.l.morris@oracle.com>,
Jann Horn <jannh@google.com>, "Kees Cook" <keescook@chromium.org>,
PaX Team <pageexec@freemail.hu>,
"Serge E. Hallyn" <serge@hallyn.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: RE: [PATCH v5 06/12] S.A.R.A.: WX protection
Date: Mon, 8 Jul 2019 12:42:15 +0000 [thread overview]
Message-ID: <b946dd861874401a910740a9adea8e8e@AcuMS.aculab.com> (raw)
In-Reply-To: <1562410493-8661-7-git-send-email-s.mesoraca16@gmail.com>
From: Salvatore Mesoraca
> Sent: 06 July 2019 11:55
...
> Executable MMAP prevention works by preventing any new executable
> allocation after the dynamic libraries have been loaded. It works under the
> assumption that, when the dynamic libraries have been finished loading, the
> RELRO section will be marked read only.
What about writing to the file of a dynamic library after it is loaded
but before it is faulted it (or after evicting it from the I$).
...
> +#define find_relro_section(ELFH, ELFP, FILE, RELRO, FOUND) do { \
> + unsigned long i; \
> + int _tmp; \
> + loff_t _pos = 0; \
> + if (ELFH.e_type == ET_DYN || ELFH.e_type == ET_EXEC) { \
> + for (i = 0; i < ELFH.e_phnum; ++i) { \
> + _pos = ELFH.e_phoff + i*sizeof(ELFP); \
> + _tmp = kernel_read(FILE, &ELFP, sizeof(ELFP), \
> + &_pos); \
> + if (_tmp != sizeof(ELFP)) \
> + break; \
> + if (ELFP.p_type == PT_GNU_RELRO) { \
> + RELRO = ELFP.p_offset >> PAGE_SHIFT; \
> + FOUND = true; \
> + break; \
> + } \
> + } \
> + } \
> +} while (0)
This is big for a #define.
Since it contains kernel_read() it can't really matter if it is
a real function.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
prev parent reply other threads:[~2019-07-08 12:42 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-06 10:54 [PATCH v5 00/12] S.A.R.A. a new stacked LSM Salvatore Mesoraca
2019-07-06 10:54 ` [PATCH v5 01/12] S.A.R.A.: add documentation Salvatore Mesoraca
2019-07-06 17:14 ` Randy Dunlap
2019-07-06 17:32 ` Salvatore Mesoraca
2019-07-13 0:14 ` James Morris
2019-07-06 10:54 ` [PATCH v5 02/12] S.A.R.A.: create framework Salvatore Mesoraca
2019-07-06 15:29 ` Randy Dunlap
2019-07-06 10:54 ` [PATCH v5 03/12] S.A.R.A.: cred blob management Salvatore Mesoraca
2019-07-12 23:35 ` James Morris
2019-07-06 10:54 ` [PATCH v5 04/12] S.A.R.A.: generic DFA for string matching Salvatore Mesoraca
2019-07-06 18:32 ` Jann Horn
2019-07-07 16:01 ` Salvatore Mesoraca
2019-07-08 17:37 ` Jann Horn
2019-10-06 16:49 ` Salvatore Mesoraca
2019-10-07 12:40 ` Jann Horn
2019-07-06 10:54 ` [PATCH v5 05/12] LSM: creation of "check_vmflags" LSM hook Salvatore Mesoraca
2019-07-06 10:54 ` [PATCH v5 07/12] LSM: creation of "pagefault_handler" " Salvatore Mesoraca
2019-07-06 10:54 ` [PATCH v5 08/12] S.A.R.A.: trampoline emulation Salvatore Mesoraca
2019-07-06 15:31 ` Randy Dunlap
2019-07-06 10:54 ` [PATCH v5 09/12] S.A.R.A.: WX protection procattr interface Salvatore Mesoraca
2019-07-06 10:54 ` [PATCH v5 10/12] S.A.R.A.: XATTRs support Salvatore Mesoraca
2019-07-06 10:54 ` [PATCH v5 11/12] S.A.R.A.: /proc/*/mem write limitation Salvatore Mesoraca
2019-07-06 18:20 ` Jann Horn
2019-07-07 16:15 ` Salvatore Mesoraca
2019-07-06 10:54 ` [PATCH v5 12/12] MAINTAINERS: take maintainership for S.A.R.A Salvatore Mesoraca
2019-07-06 14:33 ` [PATCH v5 00/12] S.A.R.A. a new stacked LSM Jordan Glover
2019-07-06 15:02 ` Salvatore Mesoraca
2019-07-07 1:16 ` James Morris
2019-07-07 15:40 ` Salvatore Mesoraca
[not found] ` <1562410493-8661-7-git-send-email-s.mesoraca16@gmail.com>
2019-07-06 15:38 ` [PATCH v5 06/12] S.A.R.A.: WX protection Randy Dunlap
[not found] ` <20190706192852.GO17978@ZenIV.linux.org.uk>
2019-07-07 15:49 ` Salvatore Mesoraca
2019-07-09 4:51 ` Kees Cook
2019-07-08 12:42 ` David Laight [this message]
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