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Kernel: Remove SmapDisablers in open(), openat() and set_thread_name()

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This patch introduces a helpful copy_string_from_user() function
that takes a bounded null-terminated string from userspace memory
and copies it into a String object.
This commit is contained in:
Andreas Kling 2020-01-05 21:51:06 +01:00
parent c4a1ea34c2
commit 80cbb72f2f
3 changed files with 37 additions and 33 deletions
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56
Kernel/Process.cpp
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@ -1600,34 +1600,22 @@ int Process::number_of_open_file_descriptors() const
return count;
}
int Process::sys$open(const Syscall::SC_open_params* params)
int Process::sys$open(const Syscall::SC_open_params* user_params)
{
if (!validate_read_typed(params))
if (!validate_read_typed(user_params))
return -EFAULT;
const char* path_data;
int path_length;
int options;
u16 mode;
Syscall::SC_open_params params;
copy_from_user(&params, user_params, sizeof(params));
auto options = params.options;
auto mode = params.mode;
{
SmapDisabler disabler;
path_data = params->path;
path_length = params->path_length;
options = params->options;
mode = params->mode;
}
if (!path_length)
if (params.path_length <= 0)
return -EINVAL;
if (!validate_read(path_data, path_length))
if (!validate_read(params.path, params.path_length))
return -EFAULT;
String path;
{
SmapDisabler disabler;
path = String(path_data, path_length);
}
String path = copy_string_from_user(params.path, params.path_length);
int fd = alloc_fd();
#ifdef DEBUG_IO
dbgprintf("%s(%u) sys$open(\"%s\") -> %d\n", name().characters(), pid(), path, fd);
@ -1645,20 +1633,22 @@ int Process::sys$open(const Syscall::SC_open_params* params)
return fd;
}
int Process::sys$openat(const Syscall::SC_openat_params* params)
int Process::sys$openat(const Syscall::SC_openat_params* user_params)
{
if (!validate_read_typed(params))
if (!validate_read_typed(user_params))
return -EFAULT;
SmapDisabler disabler;
int dirfd = params->dirfd;
const char* path = params->path;
int path_length = params->path_length;
int options = params->options;
u16 mode = params->mode;
Syscall::SC_openat_params params;
copy_from_user(&params, user_params, sizeof(params));
int dirfd = params.dirfd;
int options = params.options;
u16 mode = params.mode;
if (!validate_read(path, path_length))
if (params.path_length <= 0)
return -EINVAL;
if (!validate_read(params.path, params.path_length))
return -EFAULT;
auto path = copy_string_from_user(params.path, params.path_length);
#ifdef DEBUG_IO
dbgprintf("%s(%u) sys$openat(%d, \"%s\")\n", dirfd, name().characters(), pid(), path);
#endif
@ -3377,17 +3367,17 @@ int Process::sys$set_thread_name(int tid, const char* buffer, int buffer_size)
if (!validate_read(buffer, buffer_size))
return -EFAULT;
SmapDisabler disabler;
auto name = copy_string_from_user(buffer, buffer_size);
const size_t max_thread_name_size = 64;
if (strnlen(buffer, (size_t)buffer_size) > max_thread_name_size)
if (name.length() > max_thread_name_size)
return -EINVAL;
auto* thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return -ESRCH;
thread->set_name({ buffer, (size_t)buffer_size });
thread->set_name(name);
return 0;
}
int Process::sys$get_thread_name(int tid, char* buffer, int buffer_size)