diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 1392ee8f4848..7e3a8e1b773a 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2561,7 +2561,35 @@ noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, return 0; } -static bool clone3_args_valid(const struct kernel_clone_args *kargs) +/** + * clone3_stack_valid - check and prepare stack + * @kargs: kernel clone args + * + * Verify that the stack arguments userspace gave us are sane. + * In addition, set the stack direction for userspace since it's easy for us to + * determine. + */ +static inline bool clone3_stack_valid(struct kernel_clone_args *kargs) +{ + if (kargs->stack == 0) { + if (kargs->stack_size > 0) + return false; + } else { + if (kargs->stack_size == 0) + return false; + + if (!access_ok((void __user *)kargs->stack, kargs->stack_size)) + return false; + +#if !defined(CONFIG_STACK_GROWSUP) && !defined(CONFIG_IA64) + kargs->stack += kargs->stack_size; +#endif + } + + return true; +} + +static bool clone3_args_valid(struct kernel_clone_args *kargs) { /* * All lower bits of the flag word are taken. @@ -2581,6 +2609,9 @@ static bool clone3_args_valid(const struct kernel_clone_args *kargs) kargs->exit_signal) return false; + if (!clone3_stack_valid(kargs)) + return false; + return true; } |