diff options
author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2014-03-13 05:41:30 +0400 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2014-03-13 05:41:51 +0400 |
commit | 66cc69e34e86a231fbe68d8918c6119e3b7549a3 (patch) | |
tree | c1ea795511e9ed8ab83fda895f0151000b166629 /include/linux/kernel.h | |
parent | cff26a51da5d206d3baf871e75778da44710219d (diff) |
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.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 196d1ea86df0..471090093c67 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)] |