From: Christoph Hellwig hch@lst.de
commit 262e6ae7081df304fc625cf368d5c2cbba2bb991 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/module.h | 1 + kernel/module.c | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+)
--- a/include/linux/module.h +++ b/include/linux/module.h @@ -376,6 +376,7 @@ 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. */ --- a/kernel/module.c +++ b/kernel/module.c @@ -1429,6 +1429,24 @@ static int verify_namespace_is_imported( 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. */ static const struct kernel_symbol *resolve_symbol(struct module *mod, @@ -1454,6 +1472,14 @@ static const struct kernel_symbol *resol 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;