From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Andrew Morton <akpm@linux-foundation.org>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Helge Deller <deller@gmx.de>, Arnd Bergmann <arnd@arndb.de>,
Kees Cook <keescook@chromium.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH v2 12/13] lkdtm: Fix execute_[user]_location()
Date: Thu, 14 Oct 2021 07:50:01 +0200 [thread overview]
Message-ID: <cbee30c66890994e116a8eae8094fa8c5336f90a.1634190022.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1634190022.git.christophe.leroy@csgroup.eu>
execute_location() and execute_user_location() intent
to copy do_nothing() text and execute it at a new location.
However, at the time being it doesn't copy do_nothing() function
but do_nothing() function descriptor which still points to the
original text. So at the end it still executes do_nothing() at
its original location allthough using a copied function descriptor.
So, fix that by really copying do_nothing() text and build a new
function descriptor by copying do_nothing() function descriptor and
updating the target address with the new location.
Also fix the displayed addresses by dereferencing do_nothing()
function descriptor.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
drivers/misc/lkdtm/perms.c | 25 +++++++++++++++++++++----
include/asm-generic/sections.h | 5 +++++
2 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 5266dc28df6e..96b3ebfcb8ed 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -44,19 +44,32 @@ static noinline void do_overwritten(void)
return;
}
+static void *setup_function_descriptor(func_desc_t *fdesc, void *dst)
+{
+ memcpy(fdesc, do_nothing, sizeof(*fdesc));
+ fdesc->addr = (unsigned long)dst;
+ barrier();
+
+ return fdesc;
+}
+
static noinline void execute_location(void *dst, bool write)
{
void (*func)(void) = dst;
+ func_desc_t fdesc;
+ void *do_nothing_text = dereference_function_descriptor(do_nothing);
- pr_info("attempting ok execution at %px\n", do_nothing);
+ pr_info("attempting ok execution at %px\n", do_nothing_text);
do_nothing();
if (write == CODE_WRITE) {
- memcpy(dst, do_nothing, EXEC_SIZE);
+ memcpy(dst, do_nothing_text, EXEC_SIZE);
flush_icache_range((unsigned long)dst,
(unsigned long)dst + EXEC_SIZE);
}
pr_info("attempting bad execution at %px\n", func);
+ if (have_function_descriptors())
+ func = setup_function_descriptor(&fdesc, dst);
func();
pr_err("FAIL: func returned\n");
}
@@ -67,15 +80,19 @@ static void execute_user_location(void *dst)
/* Intentionally crossing kernel/user memory boundary. */
void (*func)(void) = dst;
+ func_desc_t fdesc;
+ void *do_nothing_text = dereference_function_descriptor(do_nothing);
- pr_info("attempting ok execution at %px\n", do_nothing);
+ pr_info("attempting ok execution at %px\n", do_nothing_text);
do_nothing();
- copied = access_process_vm(current, (unsigned long)dst, do_nothing,
+ copied = access_process_vm(current, (unsigned long)dst, do_nothing_text,
EXEC_SIZE, FOLL_WRITE);
if (copied < EXEC_SIZE)
return;
pr_info("attempting bad execution at %px\n", func);
+ if (have_function_descriptors())
+ func = setup_function_descriptor(&fdesc, dst);
func();
pr_err("FAIL: func returned\n");
}
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 76163883c6ff..d225318538bd 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -70,6 +70,11 @@ typedef struct {
} func_desc_t;
#endif
+static inline bool have_function_descriptors(void)
+{
+ return __is_defined(HAVE_FUNCTION_DESCRIPTORS);
+}
+
/* random extra sections (if any). Override
* in asm/sections.h */
#ifndef arch_is_kernel_text
--
2.31.1
next prev parent reply other threads:[~2021-10-14 6:24 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-14 5:49 [PATCH v2 00/13] Fix LKDTM for PPC64/IA64/PARISC Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 01/13] powerpc: Move 'struct ppc64_opd_entry' back into asm/elf.h Christophe Leroy
2021-10-14 21:26 ` Daniel Axtens
2021-10-15 5:57 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 02/13] powerpc: Rename 'funcaddr' to 'addr' in 'struct ppc64_opd_entry' Christophe Leroy
2021-10-14 21:45 ` Daniel Axtens
2021-10-15 4:59 ` Christophe Leroy
2021-10-15 6:01 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 03/13] powerpc: Remove func_descr_t Christophe Leroy
2021-10-14 22:17 ` Daniel Axtens
2021-10-15 5:19 ` Christophe Leroy
2021-10-15 6:11 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 04/13] powerpc: Prepare func_desc_t for refactorisation Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 05/13] ia64: Rename 'ip' to 'addr' in 'struct fdesc' Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 06/13] asm-generic: Use HAVE_FUNCTION_DESCRIPTORS to define associated stubs Christophe Leroy
2021-10-15 6:16 ` Nicholas Piggin
2021-10-15 6:24 ` Christophe Leroy
2021-10-15 8:02 ` Nicholas Piggin
2021-10-15 11:52 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 07/13] asm-generic: Define 'func_desc_t' to commonly describe function descriptors Christophe Leroy
2021-10-14 6:52 ` Arnd Bergmann
2021-10-14 5:49 ` [PATCH v2 08/13] asm-generic: Refactor dereference_[kernel]_function_descriptor() Christophe Leroy
2021-10-15 7:00 ` Nicholas Piggin
2021-10-14 5:49 ` [PATCH v2 09/13] lkdtm: Force do_nothing() out of line Christophe Leroy
2021-10-14 5:49 ` [PATCH v2 10/13] lkdtm: Really write into kernel text in WRITE_KERN Christophe Leroy
2021-10-14 5:50 ` [PATCH v2 11/13] lkdtm: Fix lkdtm_EXEC_RODATA() Christophe Leroy
2021-10-15 21:32 ` Kees Cook
2021-10-16 6:41 ` Christophe Leroy
2021-10-17 7:50 ` Christophe Leroy
2021-10-14 5:50 ` Christophe Leroy [this message]
2021-10-15 21:31 ` [PATCH v2 12/13] lkdtm: Fix execute_[user]_location() Kees Cook
2021-10-16 6:42 ` Christophe Leroy
2021-11-16 15:07 ` Christophe Leroy
2021-10-14 5:50 ` [PATCH v2 13/13] lkdtm: Add a test for function descriptors protection Christophe Leroy
2021-10-15 21:35 ` Kees Cook
2021-10-16 6:28 ` Christophe Leroy
2021-10-14 21:35 ` [PATCH v2 00/13] Fix LKDTM for PPC64/IA64/PARISC Daniel Axtens
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=cbee30c66890994e116a8eae8094fa8c5336f90a.1634190022.git.christophe.leroy@csgroup.eu \
--to=christophe.leroy@csgroup.eu \
--cc=James.Bottomley@HansenPartnership.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=benh@kernel.crashing.org \
--cc=deller@gmx.de \
--cc=gregkh@linuxfoundation.org \
--cc=keescook@chromium.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-ia64@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-parisc@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).