From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit bca014caaa6130e57f69b5bf527967aa8ee70fdd upstream.
Signing a module should only make it trusted by the specific kernel it
was built for, not anything else. Loading a signed module meant for a
kernel with a different ABI could have interesting effects.
Therefore, treat all signatures as invalid when a module is
force-loaded.
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
kernel/module.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index ec40f03aa473..a8c4d4163a41 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2491,13 +2491,18 @@ static inline void kmemleak_load_module(const struct module *mod,
#endif
#ifdef CONFIG_MODULE_SIG
-static int module_sig_check(struct load_info *info)
+static int module_sig_check(struct load_info *info, int flags)
{
int err = -ENOKEY;
const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
const void *mod = info->hdr;
- if (info->len > markerlen &&
+ /*
+ * Require flags == 0, as a module with version information
+ * removed is no longer the module that was signed
+ */
+ if (flags == 0 &&
+ info->len > markerlen &&
memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
/* We truncate the module to discard the signature */
info->len -= markerlen;
@@ -2519,7 +2524,7 @@ static int module_sig_check(struct load_info *info)
return err;
}
#else /* !CONFIG_MODULE_SIG */
-static int module_sig_check(struct load_info *info)
+static int module_sig_check(struct load_info *info, int flags)
{
return 0;
}
@@ -3247,7 +3252,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
struct module *mod;
long err;
- err = module_sig_check(info);
+ err = module_sig_check(info, flags);
if (err)
goto free_copy;
--
2.9.3
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