diff options
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_events_user.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 4f9ae63dfc5d..a29cd13caf55 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -419,6 +419,21 @@ static int user_event_enabler_write(struct user_event_mm *mm, return 0; } +static bool user_event_enabler_exists(struct user_event_mm *mm, + unsigned long uaddr, unsigned char bit) +{ + struct user_event_enabler *enabler; + struct user_event_enabler *next; + + list_for_each_entry_safe(enabler, next, &mm->enablers, link) { + if (enabler->addr == uaddr && + (enabler->values & ENABLE_VAL_BIT_MASK) == bit) + return true; + } + + return false; +} + static void user_event_enabler_update(struct user_event *user) { struct user_event_enabler *enabler; @@ -657,6 +672,22 @@ error: user_event_mm_remove(t); } +static bool current_user_event_enabler_exists(unsigned long uaddr, + unsigned char bit) +{ + struct user_event_mm *user_mm = current_user_event_mm(); + bool exists; + + if (!user_mm) + return false; + + exists = user_event_enabler_exists(user_mm, uaddr, bit); + + user_event_mm_put(user_mm); + + return exists; +} + static struct user_event_enabler *user_event_enabler_create(struct user_reg *reg, struct user_event *user, int *write_result) @@ -2048,6 +2079,16 @@ static long user_events_ioctl_reg(struct user_event_file_info *info, if (ret) return ret; + /* + * Prevent users from using the same address and bit multiple times + * within the same mm address space. This can cause unexpected behavior + * for user processes that is far easier to debug if this is explictly + * an error upon registering. + */ + if (current_user_event_enabler_exists((unsigned long)reg.enable_addr, + reg.enable_bit)) + return -EADDRINUSE; + name = strndup_user((const char __user *)(uintptr_t)reg.name_args, MAX_EVENT_DESC); |