If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag
for all modules importing these symbols, and don't allow loading
symbols from TAINT_PROPRIETARY_MODULE modules if the module previously
imported gplonly symbols. Add a anti-circumvention devices so people
don't accidentally get themselves into trouble this way.
Comment from Greg:
Ah, the proven-to-be-illegal "GPL Condom" defense :)
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/module.h | 1 +
kernel/module.c | 12 ++++++++++++
2 files changed, 13 insertions(+)
diff --git a/include/linux/module.h b/include/linux/module.h
index 30b0f5fcdb3c37..e30ed5fa33a738 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -389,6 +389,7 @@ struct module {
unsigned int num_gpl_syms;
const struct kernel_symbol *gpl_syms;
const s32 *gpl_crcs;
+ bool using_gplonly_symbols;
#ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */
diff --git a/kernel/module.c b/kernel/module.c
index afb2bfdd5134b3..04f993863ae417 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1456,6 +1456,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
if (!sym)
goto unlock;
+ if (license == GPL_ONLY)
+ mod->using_gplonly_symbols = true;
+
+ if (owner && test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) {
+ if (mod->using_gplonly_symbols) {
+ sym = NULL;
+ goto getname;
+ }
+ add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+ LOCKDEP_NOW_UNRELIABLE);
+ }
+
if (!check_version(info, name, mod, crc)) {
sym = ERR_PTR(-EINVAL);
goto getname;
--
2.27.0
+++ Christoph Hellwig [30/07/20 08:10 +0200]:
>If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag
>for all modules importing these symbols, and don't allow loading
>symbols from TAINT_PROPRIETARY_MODULE modules if the module previously
>imported gplonly symbols. Add a anti-circumvention devices so people
>don't accidentally get themselves into trouble this way.
>
>Comment from Greg:
> Ah, the proven-to-be-illegal "GPL Condom" defense :)
>
>Signed-off-by: Christoph Hellwig <[email protected]>
>Reviewed-by: Greg Kroah-Hartman <[email protected]>
>---
> include/linux/module.h | 1 +
> kernel/module.c | 12 ++++++++++++
> 2 files changed, 13 insertions(+)
>
>diff --git a/include/linux/module.h b/include/linux/module.h
>index 30b0f5fcdb3c37..e30ed5fa33a738 100644
>--- a/include/linux/module.h
>+++ b/include/linux/module.h
>@@ -389,6 +389,7 @@ struct module {
> unsigned int num_gpl_syms;
> const struct kernel_symbol *gpl_syms;
> const s32 *gpl_crcs;
>+ bool using_gplonly_symbols;
>
> #ifdef CONFIG_UNUSED_SYMBOLS
> /* unused exported symbols. */
>diff --git a/kernel/module.c b/kernel/module.c
>index afb2bfdd5134b3..04f993863ae417 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -1456,6 +1456,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
> if (!sym)
> goto unlock;
>
>+ if (license == GPL_ONLY)
>+ mod->using_gplonly_symbols = true;
>+
>+ if (owner && test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) {
>+ if (mod->using_gplonly_symbols) {
>+ sym = NULL;
>+ goto getname;
>+ }
>+ add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
>+ LOCKDEP_NOW_UNRELIABLE);
>+ }
Sorry that I didn't think of this yesterday, but I'm wondering if we
should print a warning before add_taint_module(). Maybe something
along the lines of, "%s: module uses symbols from proprietary module
%s, inheriting taint.", with %s being mod->name, owner->name. We can
check mod->taints for TAINT_PROPRIETARY_MODULE and print the warning once.
Additionally, maybe it's a good idea to print an error before goto
getname (e.g., "%s: module using GPL-only symbols uses symbols from
proprietary module %s."), so one would know why the module load
failed, right now this manifests itself as an unknown symbol error.
Otherwise, this patchset looks good to me and I agree with it in
principle. Thanks Christoph!
On Thu, Jul 30, 2020 at 04:12:32PM +0200, Jessica Yu wrote:
>> + if (owner && test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) {
>> + if (mod->using_gplonly_symbols) {
>> + sym = NULL;
>> + goto getname;
>> + }
>> + add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
>> + LOCKDEP_NOW_UNRELIABLE);
>> + }
>
> Sorry that I didn't think of this yesterday, but I'm wondering if we
> should print a warning before add_taint_module(). Maybe something
> along the lines of, "%s: module uses symbols from proprietary module
> %s, inheriting taint.", with %s being mod->name, owner->name. We can
> check mod->taints for TAINT_PROPRIETARY_MODULE and print the warning once.
>
> Additionally, maybe it's a good idea to print an error before goto
> getname (e.g., "%s: module using GPL-only symbols uses symbols from
> proprietary module %s."), so one would know why the module load
> failed, right now this manifests itself as an unknown symbol error.
>
> Otherwise, this patchset looks good to me and I agree with it in
> principle. Thanks Christoph!
What about this version? It also factors the code out into a new
helper, and replaces the add_taint_module with a simple set_bit,
as the system-wide tain must have been set before by definition:
---
From 25e928b6b691911717d30b3449e56fca3e13dba9 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <[email protected]>
Date: Tue, 28 Jul 2020 23:33:33 +0200
Subject: modules: inherit TAINT_PROPRIETARY_MODULE
If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag
for all modules importing these symbols, and don't allow loading
symbols from TAINT_PROPRIETARY_MODULE modules if the module previously
imported gplonly symbols. Add a anti-circumvention devices so people
don't accidentally get themselves into trouble this way.
Comment from Greg:
"Ah, the proven-to-be-illegal "GPL Condom" defense :)"
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/module.h | 1 +
kernel/module.c | 26 ++++++++++++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/include/linux/module.h b/include/linux/module.h
index 30b0f5fcdb3c37..e30ed5fa33a738 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -389,6 +389,7 @@ struct module {
unsigned int num_gpl_syms;
const struct kernel_symbol *gpl_syms;
const s32 *gpl_crcs;
+ bool using_gplonly_symbols;
#ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */
diff --git a/kernel/module.c b/kernel/module.c
index afb2bfdd5134b3..81d5facce28c14 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1431,6 +1431,24 @@ static int verify_namespace_is_imported(const struct load_info *info,
return 0;
}
+static bool inherit_taint(struct module *mod, struct module *owner)
+{
+ if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
+ return true;
+
+ if (mod->using_gplonly_symbols) {
+ pr_info("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
+ mod->name, owner->name);
+ return false;
+ }
+
+ if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
+ pr_info("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
+ mod->name, owner->name);
+ set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
+ }
+ return true;
+}
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod,
@@ -1456,6 +1474,14 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
if (!sym)
goto unlock;
+ if (license == GPL_ONLY)
+ mod->using_gplonly_symbols = true;
+
+ if (!inherit_taint(mod, owner)) {
+ sym = NULL;
+ goto getname;
+ }
+
if (!check_version(info, name, mod, crc)) {
sym = ERR_PTR(-EINVAL);
goto getname;
--
2.27.0
+++ Christoph Hellwig [30/07/20 18:29 +0200]:
>On Thu, Jul 30, 2020 at 04:12:32PM +0200, Jessica Yu wrote:
>>> + if (owner && test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) {
>>> + if (mod->using_gplonly_symbols) {
>>> + sym = NULL;
>>> + goto getname;
>>> + }
>>> + add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
>>> + LOCKDEP_NOW_UNRELIABLE);
>>> + }
>>
>> Sorry that I didn't think of this yesterday, but I'm wondering if we
>> should print a warning before add_taint_module(). Maybe something
>> along the lines of, "%s: module uses symbols from proprietary module
>> %s, inheriting taint.", with %s being mod->name, owner->name. We can
>> check mod->taints for TAINT_PROPRIETARY_MODULE and print the warning once.
>>
>> Additionally, maybe it's a good idea to print an error before goto
>> getname (e.g., "%s: module using GPL-only symbols uses symbols from
>> proprietary module %s."), so one would know why the module load
>> failed, right now this manifests itself as an unknown symbol error.
>>
>> Otherwise, this patchset looks good to me and I agree with it in
>> principle. Thanks Christoph!
>
>What about this version? It also factors the code out into a new
>helper, and replaces the add_taint_module with a simple set_bit,
>as the system-wide tain must have been set before by definition:
Yep, this version looks much better. See below for nits.
>---
>From 25e928b6b691911717d30b3449e56fca3e13dba9 Mon Sep 17 00:00:00 2001
>From: Christoph Hellwig <[email protected]>
>Date: Tue, 28 Jul 2020 23:33:33 +0200
>Subject: modules: inherit TAINT_PROPRIETARY_MODULE
>
>If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag
>for all modules importing these symbols, and don't allow loading
>symbols from TAINT_PROPRIETARY_MODULE modules if the module previously
>imported gplonly symbols. Add a anti-circumvention devices so people
>don't accidentally get themselves into trouble this way.
>
>Comment from Greg:
> "Ah, the proven-to-be-illegal "GPL Condom" defense :)"
>
>Signed-off-by: Christoph Hellwig <[email protected]>
>Reviewed-by: Greg Kroah-Hartman <[email protected]>
>---
> include/linux/module.h | 1 +
> kernel/module.c | 26 ++++++++++++++++++++++++++
> 2 files changed, 27 insertions(+)
>
>diff --git a/include/linux/module.h b/include/linux/module.h
>index 30b0f5fcdb3c37..e30ed5fa33a738 100644
>--- a/include/linux/module.h
>+++ b/include/linux/module.h
>@@ -389,6 +389,7 @@ struct module {
> unsigned int num_gpl_syms;
> const struct kernel_symbol *gpl_syms;
> const s32 *gpl_crcs;
>+ bool using_gplonly_symbols;
>
> #ifdef CONFIG_UNUSED_SYMBOLS
> /* unused exported symbols. */
>diff --git a/kernel/module.c b/kernel/module.c
>index afb2bfdd5134b3..81d5facce28c14 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -1431,6 +1431,24 @@ static int verify_namespace_is_imported(const struct load_info *info,
> return 0;
> }
>
>+static bool inherit_taint(struct module *mod, struct module *owner)
>+{
>+ if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
>+ return true;
>+
>+ if (mod->using_gplonly_symbols) {
>+ pr_info("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
>+ mod->name, owner->name);
pr_err() maybe?
>+ return false;
>+ }
>+
>+ if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
>+ pr_info("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
>+ mod->name, owner->name);
and pr_warn()? But otherwise this looks much better.
Thanks,
Jessica
On Fri, Jul 31, 2020 at 10:51:30AM +0200, Jessica Yu wrote:
>> + if (mod->using_gplonly_symbols) {
>> + pr_info("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
>> + mod->name, owner->name);
>
> pr_err() maybe?
>
>> + return false;
>> + }
>> +
>> + if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
>> + pr_info("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
>> + mod->name, owner->name);
>
> and pr_warn()? But otherwise this looks much better.
Ok with me. Can you just fix it up, or do you want a full resend?
+++ Christoph Hellwig [31/07/20 11:00 +0200]:
>On Fri, Jul 31, 2020 at 10:51:30AM +0200, Jessica Yu wrote:
>>> + if (mod->using_gplonly_symbols) {
>>> + pr_info("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
>>> + mod->name, owner->name);
>>
>> pr_err() maybe?
>>
>>> + return false;
>>> + }
>>> +
>>> + if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
>>> + pr_info("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
>>> + mod->name, owner->name);
>>
>> and pr_warn()? But otherwise this looks much better.
>
>Ok with me. Can you just fix it up, or do you want a full resend?
I can fix it up, no need to resend. Thanks!
On Thu, Jul 30, 2020 at 08:10:27AM +0200, Christoph Hellwig wrote:
> If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag
> for all modules importing these symbols, and don't allow loading
> symbols from TAINT_PROPRIETARY_MODULE modules if the module previously
> imported gplonly symbols. Add a anti-circumvention devices so people
> don't accidentally get themselves into trouble this way.
>
> Comment from Greg:
> Ah, the proven-to-be-illegal "GPL Condom" defense :)
>
> Signed-off-by: Christoph Hellwig <[email protected]>
> Reviewed-by: Greg Kroah-Hartman <[email protected]>
If this helps to get the next gpu related entertainment at least cc'ed to
dri-devel, maybe even using an upstream driver, I'm all for it.
Acked-by: Daniel Vetter <[email protected]>
> ---
> include/linux/module.h | 1 +
> kernel/module.c | 12 ++++++++++++
> 2 files changed, 13 insertions(+)
>
> diff --git a/include/linux/module.h b/include/linux/module.h
> index 30b0f5fcdb3c37..e30ed5fa33a738 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -389,6 +389,7 @@ struct module {
> unsigned int num_gpl_syms;
> const struct kernel_symbol *gpl_syms;
> const s32 *gpl_crcs;
> + bool using_gplonly_symbols;
>
> #ifdef CONFIG_UNUSED_SYMBOLS
> /* unused exported symbols. */
> diff --git a/kernel/module.c b/kernel/module.c
> index afb2bfdd5134b3..04f993863ae417 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -1456,6 +1456,18 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
> if (!sym)
> goto unlock;
>
> + if (license == GPL_ONLY)
> + mod->using_gplonly_symbols = true;
> +
> + if (owner && test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) {
> + if (mod->using_gplonly_symbols) {
> + sym = NULL;
> + goto getname;
> + }
> + add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
> + LOCKDEP_NOW_UNRELIABLE);
> + }
> +
> if (!check_version(info, name, mod, crc)) {
> sym = ERR_PTR(-EINVAL);
> goto getname;
> --
> 2.27.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch