[PATCH v2] modsign: log module name in the event of an error

From: Jessica Yu
Date: Mon Jul 02 2018 - 07:19:34 EST


Now that we have the load_info struct all initialized (including
info->name, which contains the name of the module) before
module_sig_check(), make the load_info struct and hence module name
available to mod_verify_sig() so that we can log the module name in the
event of an error.

Signed-off-by: Jessica Yu <jeyu@xxxxxxxxxx>
---
v2:
- remove _modlen argument and just use the passed info struct

kernel/module-internal.h | 25 ++++++++++++++++++++++++-
kernel/module.c | 22 +---------------------
kernel/module_signing.c | 12 +++++++-----
3 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/kernel/module-internal.h b/kernel/module-internal.h
index 915e123a430f..79c9be2dbbe9 100644
--- a/kernel/module-internal.h
+++ b/kernel/module-internal.h
@@ -9,4 +9,27 @@
* 2 of the Licence, or (at your option) any later version.
*/

-extern int mod_verify_sig(const void *mod, unsigned long *_modlen);
+#include <linux/elf.h>
+#include <asm/module.h>
+
+struct load_info {
+ const char *name;
+ /* pointer to module in temporary copy, freed at end of load_module() */
+ struct module *mod;
+ Elf_Ehdr *hdr;
+ unsigned long len;
+ Elf_Shdr *sechdrs;
+ char *secstrings, *strtab;
+ unsigned long symoffs, stroffs;
+ struct _ddebug *debug;
+ unsigned int num_debug;
+ bool sig_ok;
+#ifdef CONFIG_KALLSYMS
+ unsigned long mod_kallsyms_init_off;
+#endif
+ struct {
+ unsigned int sym, str, mod, vers, info, pcpu;
+ } index;
+};
+
+extern int mod_verify_sig(const void *mod, struct load_info *info);
diff --git a/kernel/module.c b/kernel/module.c
index ba45a84e4287..8a45986fd728 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -307,26 +307,6 @@ int unregister_module_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL(unregister_module_notifier);

-struct load_info {
- const char *name;
- /* pointer to module in temporary copy, freed at end of load_module() */
- struct module *mod;
- Elf_Ehdr *hdr;
- unsigned long len;
- Elf_Shdr *sechdrs;
- char *secstrings, *strtab;
- unsigned long symoffs, stroffs;
- struct _ddebug *debug;
- unsigned int num_debug;
- bool sig_ok;
-#ifdef CONFIG_KALLSYMS
- unsigned long mod_kallsyms_init_off;
-#endif
- struct {
- unsigned int sym, str, mod, vers, info, pcpu;
- } index;
-};
-
/*
* We require a truly strong try_module_get(): 0 means success.
* Otherwise an error is returned due to ongoing or failed
@@ -2778,7 +2758,7 @@ static int module_sig_check(struct load_info *info, int flags)
memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
/* We truncate the module to discard the signature */
info->len -= markerlen;
- err = mod_verify_sig(mod, &info->len);
+ err = mod_verify_sig(mod, info);
}

if (!err) {
diff --git a/kernel/module_signing.c b/kernel/module_signing.c
index 937c844bee4a..f2075ce8e4b3 100644
--- a/kernel/module_signing.c
+++ b/kernel/module_signing.c
@@ -45,10 +45,10 @@ struct module_signature {
/*
* Verify the signature on a module.
*/
-int mod_verify_sig(const void *mod, unsigned long *_modlen)
+int mod_verify_sig(const void *mod, struct load_info *info)
{
struct module_signature ms;
- size_t modlen = *_modlen, sig_len;
+ size_t sig_len, modlen = info->len;

pr_devel("==>%s(,%zu)\n", __func__, modlen);

@@ -62,10 +62,11 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
if (sig_len >= modlen)
return -EBADMSG;
modlen -= sig_len;
- *_modlen = modlen;
+ info->len = modlen;

if (ms.id_type != PKEY_ID_PKCS7) {
- pr_err("Module is not signed with expected PKCS#7 message\n");
+ pr_err("%s: Module is not signed with expected PKCS#7 message\n",
+ info->name);
return -ENOPKG;
}

@@ -76,7 +77,8 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen)
ms.__pad[0] != 0 ||
ms.__pad[1] != 0 ||
ms.__pad[2] != 0) {
- pr_err("PKCS#7 signature info has unexpected non-zero params\n");
+ pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
+ info->name);
return -EBADMSG;
}

--
2.16.4