[PATCH v2 1/3] taint: Convert to indexed initialization

From: Kees Cook
Date: Mon Feb 19 2018 - 18:54:09 EST


This converts to using indexed initializers instead of comments, adds a
comment on why the taint flags can't be an enum, and make sure that no one
forgets to update the taint_flags when adding new bits.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
include/linux/kernel.h | 1 +
kernel/panic.c | 36 +++++++++++++++++++-----------------
2 files changed, 20 insertions(+), 17 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index ce51455e2adf..62fa060a6e1a 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -533,6 +533,7 @@ extern enum system_states {
SYSTEM_RESTART,
} system_state;

+/* This cannot be an enum because some may be used in assembly source. */
#define TAINT_PROPRIETARY_MODULE 0
#define TAINT_FORCED_MODULE 1
#define TAINT_CPU_OUT_OF_SPEC 2
diff --git a/kernel/panic.c b/kernel/panic.c
index 2cfef408fec9..c5e0fd5a188e 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -308,23 +308,23 @@ EXPORT_SYMBOL(panic);
* is being removed anyway.
*/
const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
- { 'P', 'G', true }, /* TAINT_PROPRIETARY_MODULE */
- { 'F', ' ', true }, /* TAINT_FORCED_MODULE */
- { 'S', ' ', false }, /* TAINT_CPU_OUT_OF_SPEC */
- { 'R', ' ', false }, /* TAINT_FORCED_RMMOD */
- { 'M', ' ', false }, /* TAINT_MACHINE_CHECK */
- { 'B', ' ', false }, /* TAINT_BAD_PAGE */
- { 'U', ' ', false }, /* TAINT_USER */
- { 'D', ' ', false }, /* TAINT_DIE */
- { 'A', ' ', false }, /* TAINT_OVERRIDDEN_ACPI_TABLE */
- { 'W', ' ', false }, /* TAINT_WARN */
- { 'C', ' ', true }, /* TAINT_CRAP */
- { 'I', ' ', false }, /* TAINT_FIRMWARE_WORKAROUND */
- { 'O', ' ', true }, /* TAINT_OOT_MODULE */
- { 'E', ' ', true }, /* TAINT_UNSIGNED_MODULE */
- { 'L', ' ', false }, /* TAINT_SOFTLOCKUP */
- { 'K', ' ', true }, /* TAINT_LIVEPATCH */
- { 'X', ' ', true }, /* TAINT_AUX */
+ [ TAINT_PROPRIETARY_MODULE ] = { 'P', 'G', true },
+ [ TAINT_FORCED_MODULE ] = { 'F', ' ', true },
+ [ TAINT_CPU_OUT_OF_SPEC ] = { 'S', ' ', false },
+ [ TAINT_FORCED_RMMOD ] = { 'R', ' ', false },
+ [ TAINT_MACHINE_CHECK ] = { 'M', ' ', false },
+ [ TAINT_BAD_PAGE ] = { 'B', ' ', false },
+ [ TAINT_USER ] = { 'U', ' ', false },
+ [ TAINT_DIE ] = { 'D', ' ', false },
+ [ TAINT_OVERRIDDEN_ACPI_TABLE ] = { 'A', ' ', false },
+ [ TAINT_WARN ] = { 'W', ' ', false },
+ [ TAINT_CRAP ] = { 'C', ' ', true },
+ [ TAINT_FIRMWARE_WORKAROUND ] = { 'I', ' ', false },
+ [ TAINT_OOT_MODULE ] = { 'O', ' ', true },
+ [ TAINT_UNSIGNED_MODULE ] = { 'E', ' ', true },
+ [ TAINT_SOFTLOCKUP ] = { 'L', ' ', false },
+ [ TAINT_LIVEPATCH ] = { 'K', ' ', true },
+ [ TAINT_AUX ] = { 'X', ' ', true },
};

/**
@@ -354,6 +354,8 @@ const char *print_tainted(void)
{
static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];

+ BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);
+
if (tainted_mask) {
char *s;
int i;
--
2.7.4