[PATCH 3.10 172/180] module: Invalidate signatures on force-loaded modules
From: Willy Tarreau <w@1wt.eu>
Date: 2016-08-21 16:05:00
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Ben Hutchings <redacted> 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 <redacted> Signed-off-by: Rusty Russell <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Willy Tarreau <w@1wt.eu> --- kernel/module.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index f8a4f48..2c87e52 100644
--- a/kernel/module.c
+++ b/kernel/module.c@@ -2475,13 +2475,18 @@ 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;
@@ -2503,7 +2508,7 @@ 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; }
@@ -3228,7 +3233,7 @@ 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;
--
2.8.0.rc2.1.gbe9624a