From: Peter Zijlstra <peterz@infradead.org>
To: jeyu@kernel.org
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
keescook@chromium.org, Josh Poimboeuf <jpoimboe@redhat.com>,
Miroslav Benes <mbenes@suse.cz>
Subject: [PATCH] module: Harden STRICT_MODULE_RWX
Date: Fri, 3 Apr 2020 18:37:16 +0200 [thread overview]
Message-ID: <20200403163716.GV20730@hirez.programming.kicks-ass.net> (raw)
We're very close to enforcing W^X memory, refuse to load modules that
violate this principle per construction.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
---
kernel/module.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2044,9 +2044,28 @@ static void module_enable_x(const struct
frob_text(&mod->core_layout, set_memory_x);
frob_text(&mod->init_layout, set_memory_x);
}
+
+static int module_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ int i;
+
+ for (i = 0; i < hdr->e_shnum; i++) {
+ if (sechdrs[i].sh_flags & (SHF_EXECINSTR|SHF_WRITE))
+ return -ENOEXEC;
+ }
+
+ return 0;
+}
+
#else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
static void module_enable_nx(const struct module *mod) { }
static void module_enable_x(const struct module *mod) { }
+static int module_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ return 0;
+}
#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
@@ -3378,6 +3397,11 @@ static struct module *layout_and_allocat
if (err < 0)
return ERR_PTR(err);
+ err = module_rwx_sections(info->hdr, info->sechdrs,
+ info->secstrings, info->mod);
+ if (err < 0)
+ return ERR_PTR(err);
+
/* We will do a special allocation for per-cpu sections later. */
info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
next reply other threads:[~2020-04-03 16:37 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-03 16:37 Peter Zijlstra [this message]
2020-04-03 16:56 ` [PATCH] module: Harden STRICT_MODULE_RWX Josh Poimboeuf
2020-04-03 17:08 ` Peter Zijlstra
2020-04-06 9:55 ` Miroslav Benes
2020-04-06 10:46 ` Jessica Yu
2020-04-06 11:27 ` Peter Zijlstra
2020-04-06 12:53 ` Jessica Yu
2020-04-06 14:11 ` Peter Zijlstra
2020-04-07 7:43 ` Miroslav Benes
2020-04-09 16:55 ` Miroslav Benes
2020-04-10 9:04 ` Jessica Yu
2020-04-03 16:59 ` Josh Poimboeuf
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=20200403163716.GV20730@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=jeyu@kernel.org \
--cc=jpoimboe@redhat.com \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mbenes@suse.cz \
--cc=tglx@linutronix.de \
/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).