[PATCH v3] module: Add log info for verifying module signature
Add log information in kernel-space when loading module failures.
Try to load the unsigned module and the module with bad signature
when set 1 to /sys/module/module/parameters/sig_enforce.
Unsigned module case:
(linux) insmod unsigned.ko
[ 18.714661] Loading of unsigned module is rejected
insmod: can't insert 'unsigned.ko': Key was rejected by service
(linux)
Bad signature module case:
(linux) insmod bad_signature.ko
insmod: can't insert 'bad_signature.ko': Key was rejected by service
(linux)
There have different logging behavior the bad signature case only log
in user-space, add log info for fatal errors in module_sig_check().
Signed-off-by: Yusong Gao
---
V3: Clarify the message type and the error code meaning.
V2: Change print level from notice to debug.
---
kernel/module/signing.c | 27 +++
1 file changed, 27 insertions(+)
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index a2ff4242e623..826cdab8e3e4 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -67,6 +67,31 @@ int mod_verify_sig(const void *mod, struct load_info *info)
NULL, NULL);
}
+static const char *mod_decode_error(int errno)
+{
+ char *errstr = "Unrecognized error";
+
+ switch (errno) {
+ case -ENOMEM:
+ errstr = "Out of memory";
+ break;
+ case -EINVAL:
+ errstr = "Invalid argument";
+ break;
+ case -EBADMSG:
+ errstr = "Invaild module signature format";
+ break;
+ case -EMSGSIZE:
+ errstr = "Message too long";
+ break;
+ case -EKEYREJECTED:
+ errstr = "Key was rejected by service";
+ break;
+ }
+
+ return errstr;
+}
+
int module_sig_check(struct load_info *info, int flags)
{
int err = -ENODATA;
@@ -113,6 +138,8 @@ int module_sig_check(struct load_info *info, int flags)
* unparseable signatures, and signature check failures --
* even if signatures aren't required.
*/
+ pr_debug("Verifying module signature failed: %s\n",
+mod_decode_error(err));
return err;
}
--
2.34.1
[PATCH v2] module: Add log information for loading module failures
Add log information in kernel-space when loading module failures.
Try to load the unsigned module and the module with bad signature
when set 1 to /sys/module/module/parameters/sig_enforce.
Unsigned module case:
(linux) insmod unsigned.ko
[ 18.714661] Loading of unsigned module is rejected
insmod: can't insert 'unsigned.ko': Key was rejected by service
(linux)
Bad signature module case:
(linux) insmod bad_signature.ko
insmod: can't insert 'bad_signature.ko': Key was rejected by service
(linux)
There have different logging behavior the bad signature case only log
in user-space, add log info for fatal errors in module_sig_check().
Signed-off-by: Yusong Gao
---
V2: Change print level from notice to debug.
---
kernel/module/signing.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index a2ff4242e623..b0c7b30e4d89 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -113,6 +113,7 @@ int module_sig_check(struct load_info *info, int flags)
* unparseable signatures, and signature check failures --
* even if signatures aren't required.
*/
+ pr_debug("Loading module failed (errno=%d)\n", -err);
return err;
}
--
2.34.1
Re: [PATCH] module: Add log information for loading module failures
On 6/19/24 02:54, Luis Chamberlain wrote:
On Fri, Jun 14, 2024 at 09:25:19AM +, Yusong Gao wrote:
Add log information in kernel-space when loading module failures.
Try to load the unsigned module and the module with bad signature
when set 1 to /sys/module/module/parameters/sig_enforce.
Unsigned module case:
(linux) insmod unsigned.ko
[ 18.714661] Loading of unsigned module is rejected
insmod: can't insert 'unsigned.ko': Key was rejected by service
(linux)
Bad signature module case:
(linux) insmod bad_signature.ko
insmod: can't insert 'bad_signature.ko': Key was rejected by service
(linux)
There have different logging behavior the bad signature case only log
in user-space, add log info for fatal errors in module_sig_check().
Signed-off-by: Yusong Gao
---
kernel/module/signing.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index a2ff4242e623..6a6493c8f7e4 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -113,6 +113,7 @@ int module_sig_check(struct load_info *info, int flags)
* unparseable signatures, and signature check failures --
* even if signatures aren't required.
*/
+ pr_notice("Loading module failed (errno=%d)\n", -err);
return err;
I welcome pr_debug() messages but if we were to add a regular print for every
single type of failure we'd clutter the code, we don't want that.
Luis
Thanks for your reply!
Agreed. I'll make that change. The reason I select the notice print
level is because I found the codes in module_sig_check() use notice
level when signature enforced. In fact the pr_debug() is more suitable
for this scene.
BR, Yusong Gao
[PATCH] module: Add log information for loading module failures
Add log information in kernel-space when loading module failures.
Try to load the unsigned module and the module with bad signature
when set 1 to /sys/module/module/parameters/sig_enforce.
Unsigned module case:
(linux) insmod unsigned.ko
[ 18.714661] Loading of unsigned module is rejected
insmod: can't insert 'unsigned.ko': Key was rejected by service
(linux)
Bad signature module case:
(linux) insmod bad_signature.ko
insmod: can't insert 'bad_signature.ko': Key was rejected by service
(linux)
There have different logging behavior the bad signature case only log
in user-space, add log info for fatal errors in module_sig_check().
Signed-off-by: Yusong Gao
---
kernel/module/signing.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/module/signing.c b/kernel/module/signing.c
index a2ff4242e623..6a6493c8f7e4 100644
--- a/kernel/module/signing.c
+++ b/kernel/module/signing.c
@@ -113,6 +113,7 @@ int module_sig_check(struct load_info *info, int flags)
* unparseable signatures, and signature check failures --
* even if signatures aren't required.
*/
+ pr_notice("Loading module failed (errno=%d)\n", -err);
return err;
}
--
2.34.1
