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 v2] module: Harden STRICT_MODULE_RWX
Date: Fri, 3 Apr 2020 19:13:03 +0200 [thread overview]
Message-ID: <20200403171303.GK20760@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>
---
kernel/module.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2044,9 +2044,29 @@ 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_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
+ int i;
+
+ for (i = 0; i < hdr->e_shnum; i++) {
+ if ((sechdrs[i].sh_flags & shf_wx) == shf_wx)
+ 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_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
+ char *secstrings, struct module *mod)
+{
+ return 0;
+}
#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
@@ -3378,6 +3398,11 @@ static struct module *layout_and_allocat
if (err < 0)
return ERR_PTR(err);
+ err = module_enforce_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 17:13 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-03 17:13 Peter Zijlstra [this message]
2020-04-03 20:31 ` [PATCH v2] module: Harden STRICT_MODULE_RWX Kees Cook
2020-04-08 15:32 ` Jessica Yu
2020-04-08 15:43 ` [PATCH] module: break nested ARCH_HAS_STRICT_MODULE_RWX and STRICT_MODULE_RWX #ifdefs Jessica Yu
2020-04-08 15:57 ` [PATCH v2] module: Harden STRICT_MODULE_RWX Peter Zijlstra
2020-04-08 16:20 ` Jessica Yu
2020-08-08 8:12 ` Mauro Carvalho Chehab
2020-08-10 9:25 ` Jessica Yu
2020-08-10 15:06 ` Jessica Yu
2020-08-11 14:34 ` Mauro Carvalho Chehab
2020-08-11 14:55 ` peterz
2020-08-11 15:27 ` Mauro Carvalho Chehab
2020-08-11 16:01 ` Jessica Yu
2020-08-11 16:57 ` Will Deacon
2020-08-11 17:59 ` peterz
2020-08-11 21:29 ` Peter Zijlstra
2020-08-12 8:56 ` Ard Biesheuvel
2020-08-12 10:40 ` peterz
2020-08-12 11:41 ` Jessica Yu
2020-08-12 13:14 ` H.J. Lu
2020-08-12 12:56 ` Will Deacon
2020-08-12 14:15 ` Szabolcs Nagy
2020-08-12 16:00 ` Jessica Yu
2020-08-12 16:37 ` Ard Biesheuvel
2020-08-12 16:42 ` Szabolcs Nagy
2020-08-13 9:00 ` Will Deacon
2020-08-12 20:00 ` Peter Zijlstra
2020-08-13 8:36 ` Ard Biesheuvel
2020-08-13 13:04 ` Jessica Yu
2020-08-13 13:07 ` Ard Biesheuvel
2020-08-21 12:20 ` Will Deacon
2020-08-21 12:27 ` Ard Biesheuvel
2020-08-21 12:30 ` Will Deacon
2020-08-22 13:47 ` Ard Biesheuvel
2020-08-24 15:24 ` Jessica Yu
2020-08-25 1:54 ` Masahiro Yamada
2020-08-31 9:46 ` Jessica Yu
2020-08-31 10:42 ` Masahiro Yamada
2020-08-31 13:25 ` Ard Biesheuvel
2020-08-31 15:31 ` Jessica Yu
2020-08-31 15:46 ` Masahiro Yamada
2020-09-03 12:37 ` Jessica Yu
2020-09-01 12:51 ` Will Deacon
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