summaryrefslogtreecommitdiffstats
path: root/include/linux/kernel.h
diff options
context:
space:
mode:
authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>2014-03-13 12:11:30 +1030
committerRusty Russell <rusty@rustcorp.com.au>2014-03-13 12:11:51 +1030
commit66cc69e34e86a231fbe68d8918c6119e3b7549a3 (patch)
treec1ea795511e9ed8ab83fda895f0151000b166629 /include/linux/kernel.h
parentcff26a51da5d206d3baf871e75778da44710219d (diff)
downloadop-kernel-dev-66cc69e34e86a231fbe68d8918c6119e3b7549a3.zip
op-kernel-dev-66cc69e34e86a231fbe68d8918c6119e3b7549a3.tar.gz
Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
Users have reported being unable to trace non-signed modules loaded within a kernel supporting module signature. This is caused by tracepoint.c:tracepoint_module_coming() refusing to take into account tracepoints sitting within force-loaded modules (TAINT_FORCED_MODULE). The reason for this check, in the first place, is that a force-loaded module may have a struct module incompatible with the layout expected by the kernel, and can thus cause a kernel crash upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y. Tracepoints, however, specifically accept TAINT_OOT_MODULE and TAINT_CRAP, since those modules do not lead to the "very likely system crash" issue cited above for force-loaded modules. With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed module is tainted re-using the TAINT_FORCED_MODULE taint flag. Unfortunately, this means that Tracepoints treat that module as a force-loaded module, and thus silently refuse to consider any tracepoint within this module. Since an unsigned module does not fit within the "very likely system crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag to specifically address this taint behavior, and accept those modules within Tracepoints. We use the letter 'X' as a taint flag character for a module being loaded that doesn't know how to sign its name (proposed by Steven Rostedt). Also add the missing 'O' entry to trace event show_module_flags() list for the sake of completeness. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> NAKed-by: Ingo Molnar <mingo@redhat.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: David Howells <dhowells@redhat.com> CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'include/linux/kernel.h')
-rw-r--r--include/linux/kernel.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 196d1ea..4710900 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -469,6 +469,7 @@ extern enum system_states {
#define TAINT_CRAP 10
#define TAINT_FIRMWARE_WORKAROUND 11
#define TAINT_OOT_MODULE 12
+#define TAINT_UNSIGNED_MODULE 13
extern const char hex_asc[];
#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
OpenPOWER on IntegriCloud