Messages in this thread Patch in this message | | | Date | Fri, 31 Jul 2020 10:51:30 +0200 | From | Jessica Yu <> | Subject | Re: [PATCH 8/8] modules: inherit TAINT_PROPRIETARY_MODULE |
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+++ 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 <hch@lst.de> >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 <hch@lst.de> >Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >--- > 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
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