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modules: inherit TAINT_PROPRIETARY_MODULE

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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 :)"

[jeyu: pr_info -> pr_err and pr_warn as per discussion]
Link: http://lore.kernel.org/r/20200730162957.GA22469@lst.de
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
This commit is contained in:
Christoph Hellwig 2020-07-28 23:33:33 +02:00 committed by Jessica Yu
parent ef1dac6021
commit 262e6ae708
2 changed files with 27 additions and 0 deletions
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1
include/linux/module.h
View File

@ -389,6 +389,7 @@ struct module {
unsigned int num_gpl_syms; unsigned int num_gpl_syms;
const struct kernel_symbol *gpl_syms; const struct kernel_symbol *gpl_syms;
const s32 *gpl_crcs; const s32 *gpl_crcs;
bool using_gplonly_symbols;
#ifdef CONFIG_UNUSED_SYMBOLS #ifdef CONFIG_UNUSED_SYMBOLS
/* unused exported symbols. */ /* unused exported symbols. */

26
kernel/module.c
View File

@ -1431,6 +1431,24 @@ static int verify_namespace_is_imported(const struct load_info *info,
return 0; 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_err("%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_warn("%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. */ /* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod, 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) if (!sym)
goto unlock; 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)) { if (!check_version(info, name, mod, crc)) {
sym = ERR_PTR(-EINVAL); sym = ERR_PTR(-EINVAL);
goto getname; goto getname;