lkdtm, kprobes: Convert from jprobes to kprobes

The jprobes subsystem is being removed, so convert to using kprobes instead.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171020133127.GA18360@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 981b3ef71e477ab976e67e20280271e8f133655a..ed7f0c61c59a969d4b57e253a0019c8dbb766ab4 100644 (file)
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -56,122 +56,54 @@ static ssize_t direct_entry(struct file *f, const char __user *user_buf,
                            size_t count, loff_t *off);
 
 #ifdef CONFIG_KPROBES
-static void lkdtm_handler(void);
+static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
 static ssize_t lkdtm_debugfs_entry(struct file *f,
                                   const char __user *user_buf,
                                   size_t count, loff_t *off);
-
-
-/* jprobe entry point handlers. */
-static unsigned int jp_do_irq(unsigned int irq)
-{
-       lkdtm_handler();
-       jprobe_return();
-       return 0;
-}
-
-static irqreturn_t jp_handle_irq_event(unsigned int irq,
-                                      struct irqaction *action)
-{
-       lkdtm_handler();
-       jprobe_return();
-       return 0;
-}
-
-static void jp_tasklet_action(struct softirq_action *a)
-{
-       lkdtm_handler();
-       jprobe_return();
-}
-
-static void jp_ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
-{
-       lkdtm_handler();
-       jprobe_return();
-}
-
-struct scan_control;
-
-static unsigned long jp_shrink_inactive_list(unsigned long max_scan,
-                                            struct zone *zone,
-                                            struct scan_control *sc)
-{
-       lkdtm_handler();
-       jprobe_return();
-       return 0;
-}
-
-static int jp_hrtimer_start(struct hrtimer *timer, ktime_t tim,
-                           const enum hrtimer_mode mode)
-{
-       lkdtm_handler();
-       jprobe_return();
-       return 0;
-}
-
-static int jp_scsi_dispatch_cmd(struct scsi_cmnd *cmd)
-{
-       lkdtm_handler();
-       jprobe_return();
-       return 0;
-}
-
-# ifdef CONFIG_IDE
-static int jp_generic_ide_ioctl(ide_drive_t *drive, struct file *file,
-                       struct block_device *bdev, unsigned int cmd,
-                       unsigned long arg)
-{
-       lkdtm_handler();
-       jprobe_return();
-       return 0;
-}
-# endif
+# define CRASHPOINT_KPROBE(_symbol)                            \
+               .kprobe = {                                     \
+                       .symbol_name = (_symbol),               \
+                       .pre_handler = lkdtm_kprobe_handler,    \
+               },
+# define CRASHPOINT_WRITE(_symbol)                             \
+               (_symbol) ? lkdtm_debugfs_entry : direct_entry
+#else
+# define CRASHPOINT_KPROBE(_symbol)
+# define CRASHPOINT_WRITE(_symbol)             direct_entry
 #endif
 
 /* Crash points */
 struct crashpoint {
        const char *name;
        const struct file_operations fops;
-       struct jprobe jprobe;
+       struct kprobe kprobe;
 };
 
-#define CRASHPOINT(_name, _write, _symbol, _entry)             \
+#define CRASHPOINT(_name, _symbol)                             \
        {                                                       \
                .name = _name,                                  \
                .fops = {                                       \
                        .read   = lkdtm_debugfs_read,           \
                        .llseek = generic_file_llseek,          \
                        .open   = lkdtm_debugfs_open,           \
-                       .write  = _write,                       \
-               },                                              \
-               .jprobe = {                                     \
-                       .kp.symbol_name = _symbol,              \
-                       .entry = (kprobe_opcode_t *)_entry,     \
+                       .write  = CRASHPOINT_WRITE(_symbol)     \
                },                                              \
+               CRASHPOINT_KPROBE(_symbol)                      \
        }
 
 /* Define the possible places where we can trigger a crash point. */
-struct crashpoint crashpoints[] = {
-       CRASHPOINT("DIRECT",                    direct_entry,
-                  NULL,                        NULL),
+static struct crashpoint crashpoints[] = {
+       CRASHPOINT("DIRECT",             NULL),
 #ifdef CONFIG_KPROBES
-       CRASHPOINT("INT_HARDWARE_ENTRY",        lkdtm_debugfs_entry,
-                  "do_IRQ",                    jp_do_irq),
-       CRASHPOINT("INT_HW_IRQ_EN",             lkdtm_debugfs_entry,
-                  "handle_IRQ_event",          jp_handle_irq_event),
-       CRASHPOINT("INT_TASKLET_ENTRY",         lkdtm_debugfs_entry,
-                  "tasklet_action",            jp_tasklet_action),
-       CRASHPOINT("FS_DEVRW",                  lkdtm_debugfs_entry,
-                  "ll_rw_block",               jp_ll_rw_block),
-       CRASHPOINT("MEM_SWAPOUT",               lkdtm_debugfs_entry,
-                  "shrink_inactive_list",      jp_shrink_inactive_list),
-       CRASHPOINT("TIMERADD",                  lkdtm_debugfs_entry,
-                  "hrtimer_start",             jp_hrtimer_start),
-       CRASHPOINT("SCSI_DISPATCH_CMD",         lkdtm_debugfs_entry,
-                  "scsi_dispatch_cmd",         jp_scsi_dispatch_cmd),
+       CRASHPOINT("INT_HARDWARE_ENTRY", "do_IRQ"),
+       CRASHPOINT("INT_HW_IRQ_EN",      "handle_IRQ_event"),
+       CRASHPOINT("INT_TASKLET_ENTRY",  "tasklet_action"),
+       CRASHPOINT("FS_DEVRW",           "ll_rw_block"),
+       CRASHPOINT("MEM_SWAPOUT",        "shrink_inactive_list"),
+       CRASHPOINT("TIMERADD",           "hrtimer_start"),
+       CRASHPOINT("SCSI_DISPATCH_CMD",  "scsi_dispatch_cmd"),
 # ifdef CONFIG_IDE
-       CRASHPOINT("IDE_CORE_CP",               lkdtm_debugfs_entry,
-                  "generic_ide_ioctl",         jp_generic_ide_ioctl),
+       CRASHPOINT("IDE_CORE_CP",        "generic_ide_ioctl"),
 # endif
 #endif
 };
@@ -254,8 +186,8 @@ struct crashtype crashtypes[] = {
 };
 
 
-/* Global jprobe entry and crashtype. */
-static struct jprobe *lkdtm_jprobe;
+/* Global kprobe entry and crashtype. */
+static struct kprobe *lkdtm_kprobe;
 struct crashpoint *lkdtm_crashpoint;
 struct crashtype *lkdtm_crashtype;
 
@@ -298,7 +230,8 @@ static struct crashtype *find_crashtype(const char *name)
  */
 static noinline void lkdtm_do_action(struct crashtype *crashtype)
 {
-       BUG_ON(!crashtype || !crashtype->func);
+       if (WARN_ON(!crashtype || !crashtype->func))
+               return;
        crashtype->func();
 }
 
@@ -308,22 +241,22 @@ static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
        int ret;
 
        /* If this doesn't have a symbol, just call immediately. */
-       if (!crashpoint->jprobe.kp.symbol_name) {
+       if (!crashpoint->kprobe.symbol_name) {
                lkdtm_do_action(crashtype);
                return 0;
        }
 
-       if (lkdtm_jprobe != NULL)
-               unregister_jprobe(lkdtm_jprobe);
+       if (lkdtm_kprobe != NULL)
+               unregister_kprobe(lkdtm_kprobe);
 
        lkdtm_crashpoint = crashpoint;
        lkdtm_crashtype = crashtype;
-       lkdtm_jprobe = &crashpoint->jprobe;
-       ret = register_jprobe(lkdtm_jprobe);
+       lkdtm_kprobe = &crashpoint->kprobe;
+       ret = register_kprobe(lkdtm_kprobe);
        if (ret < 0) {
-               pr_info("Couldn't register jprobe %s\n",
-                       crashpoint->jprobe.kp.symbol_name);
-               lkdtm_jprobe = NULL;
+               pr_info("Couldn't register kprobe %s\n",
+                       crashpoint->kprobe.symbol_name);
+               lkdtm_kprobe = NULL;
                lkdtm_crashpoint = NULL;
                lkdtm_crashtype = NULL;
        }
@@ -336,13 +269,14 @@ static int lkdtm_register_cpoint(struct crashpoint *crashpoint,
 static int crash_count = DEFAULT_COUNT;
 static DEFINE_SPINLOCK(crash_count_lock);
 
-/* Called by jprobe entry points. */
-static void lkdtm_handler(void)
+/* Called by kprobe entry points. */
+static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
 {
        unsigned long flags;
        bool do_it = false;
 
-       BUG_ON(!lkdtm_crashpoint || !lkdtm_crashtype);
+       if (WARN_ON(!lkdtm_crashpoint || !lkdtm_crashtype))
+               return 0;
 
        spin_lock_irqsave(&crash_count_lock, flags);
        crash_count--;
@@ -357,6 +291,8 @@ static void lkdtm_handler(void)
 
        if (do_it)
                lkdtm_do_action(lkdtm_crashtype);
+
+       return 0;
 }
 
 static ssize_t lkdtm_debugfs_entry(struct file *f,
@@ -556,8 +492,8 @@ static void __exit lkdtm_module_exit(void)
        /* Handle test-specific clean-up. */
        lkdtm_usercopy_exit();
 
-       if (lkdtm_jprobe != NULL)
-               unregister_jprobe(lkdtm_jprobe);
+       if (lkdtm_kprobe != NULL)
+               unregister_kprobe(lkdtm_kprobe);
 
        pr_info("Crash point unregistered\n");
 }