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Date: Wed, 7 Sep 2016 15:13:39 +0200
From: Petr Mladek <pmladek@...e.com>
To: Rusty Russell <rusty@...tcorp.com.au>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Jiri Kosina <jkosina@...e.cz>,
Josh Poimboeuf <jpoimboe@...hat.com>,
live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
Petr Mladek <pmladek@...e.com>
Subject: [PATCH] module/taint: Automatically increase the buffer size for new taint flags
The commit 66cc69e34e86a231 ("Fix: module signature vs tracepoints:
add new TAINT_UNSIGNED_MODULE") updated module_taint_flags() to
potentially print one more character. But it did not increase the
size of the corresponding buffers in m_show() and print_modules().
We have recently done the same mistake when adding a taint flag
for livepatching, see
https://lkml.kernel.org/g/cfba2c823bb984690b73572aaae1db596b54a082.1472137475.git.jpoimboe@redhat.com
Let's convert the taint flags into enum and handle the buffer size
almost automatically.
It is not optimal because only few taint flags can be printed by
module_taint_flags(). But better be on the safe side. IMHO, it is
not worth the optimization and this is a good compromise.
Signed-off-by: Petr Mladek <pmladek@...e.com>
---
include/linux/kernel.h | 44 ++++++++++++++++++++++++--------------------
kernel/module.c | 8 ++++++--
kernel/panic.c | 4 ++--
3 files changed, 32 insertions(+), 24 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index d96a6118d26a..1809bc82b7a5 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -472,14 +472,10 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
if (panic_timeout == arch_default_timeout)
panic_timeout = timeout;
}
-extern const char *print_tainted(void);
enum lockdep_ok {
LOCKDEP_STILL_OK,
LOCKDEP_NOW_UNRELIABLE
};
-extern void add_taint(unsigned flag, enum lockdep_ok);
-extern int test_taint(unsigned flag);
-extern unsigned long get_taint(void);
extern int root_mountflags;
extern bool early_boot_irqs_disabled;
@@ -493,22 +489,30 @@ extern enum system_states {
SYSTEM_RESTART,
} system_state;
-#define TAINT_PROPRIETARY_MODULE 0
-#define TAINT_FORCED_MODULE 1
-#define TAINT_CPU_OUT_OF_SPEC 2
-#define TAINT_FORCED_RMMOD 3
-#define TAINT_MACHINE_CHECK 4
-#define TAINT_BAD_PAGE 5
-#define TAINT_USER 6
-#define TAINT_DIE 7
-#define TAINT_OVERRIDDEN_ACPI_TABLE 8
-#define TAINT_WARN 9
-#define TAINT_CRAP 10
-#define TAINT_FIRMWARE_WORKAROUND 11
-#define TAINT_OOT_MODULE 12
-#define TAINT_UNSIGNED_MODULE 13
-#define TAINT_SOFTLOCKUP 14
-#define TAINT_LIVEPATCH 15
+enum taint_flags {
+ TAINT_PROPRIETARY_MODULE, /* 0 */
+ TAINT_FORCED_MODULE, /* 1 */
+ TAINT_CPU_OUT_OF_SPEC, /* 2 */
+ TAINT_FORCED_RMMOD, /* 3 */
+ TAINT_MACHINE_CHECK, /* 4 */
+ TAINT_BAD_PAGE, /* 5 */
+ TAINT_USER, /* 6 */
+ TAINT_DIE, /* 7 */
+ TAINT_OVERRIDDEN_ACPI_TABLE, /* 8 */
+ TAINT_WARN, /* 9 */
+ TAINT_CRAP, /* 10 */
+ TAINT_FIRMWARE_WORKAROUND, /* 11 */
+ TAINT_OOT_MODULE, /* 12 */
+ TAINT_UNSIGNED_MODULE, /* 13 */
+ TAINT_SOFTLOCKUP, /* 14 */
+ TAINT_LIVEPATCH, /* 15 */
+ TAINT_FLAGS_COUNT /* keep last! */
+};
+
+extern const char *print_tainted(void);
+extern void add_taint(enum taint_flags flag, enum lockdep_ok);
+extern int test_taint(enum taint_flags flag);
+extern unsigned long get_taint(void);
extern const char hex_asc[];
#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
diff --git a/kernel/module.c b/kernel/module.c
index 529efae9f481..fb6c0d425b47 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4036,6 +4036,10 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
}
#endif /* CONFIG_KALLSYMS */
+/* Maximum number of characters written by module_flags() */
+#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
+
+/* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
static char *module_flags(struct module *mod, char *buf)
{
int bx = 0;
@@ -4080,7 +4084,7 @@ static void m_stop(struct seq_file *m, void *p)
static int m_show(struct seq_file *m, void *p)
{
struct module *mod = list_entry(p, struct module, list);
- char buf[8];
+ char buf[MODULE_FLAGS_BUF_SIZE];
/* We always ignore unformed modules. */
if (mod->state == MODULE_STATE_UNFORMED)
@@ -4251,7 +4255,7 @@ EXPORT_SYMBOL_GPL(__module_text_address);
void print_modules(void)
{
struct module *mod;
- char buf[8];
+ char buf[MODULE_FLAGS_BUF_SIZE];
printk(KERN_DEFAULT "Modules linked in:");
/* Most callers should already have preempt disabled, but make sure */
diff --git a/kernel/panic.c b/kernel/panic.c
index ca8cea1ef673..e90125bf9238 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -334,7 +334,7 @@ const char *print_tainted(void)
return buf;
}
-int test_taint(unsigned flag)
+int test_taint(enum taint_flags flag)
{
return test_bit(flag, &tainted_mask);
}
@@ -353,7 +353,7 @@ unsigned long get_taint(void)
* If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
* some notewortht-but-not-corrupting cases, it can be set to true.
*/
-void add_taint(unsigned flag, enum lockdep_ok lockdep_ok)
+void add_taint(enum taint_flags flag, enum lockdep_ok lockdep_ok)
{
if (lockdep_ok == LOCKDEP_NOW_UNRELIABLE && __debug_locks_off())
pr_warn("Disabling lock debugging due to kernel taint\n");
--
1.8.5.6
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