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Kernel: Pass characters+length to link()

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This commit is contained in:
Andreas Kling 2020-01-10 21:26:47 +01:00
parent 416c7ac2b5
commit 485443bfca
5 changed files with 35 additions and 7 deletions
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22
Kernel/Process.cpp
View file

@ -1564,6 +1564,15 @@ bool Process::validate(const Syscall::MutableBufferArgument<DataType, SizeType>&
return validate_write(buffer.data, buffer.size); return validate_write(buffer.data, buffer.size);
} }
String Process::validate_and_copy_string_from_user(const Syscall::StringArgument& string) const
{
if (!validate_read(string.characters, string.length))
return {};
SmapDisabler disabler;
size_t length = strnlen(string.characters, string.length);
return String(string.characters, length);
}
int Process::sys$readlink(const Syscall::SC_readlink_params* user_params) int Process::sys$readlink(const Syscall::SC_readlink_params* user_params)
{ {
if (!validate_read_typed(user_params)) if (!validate_read_typed(user_params))
@ -2548,14 +2557,17 @@ Custody& Process::current_directory()
return *m_cwd; return *m_cwd;
} }
int Process::sys$link(const char* old_path, const char* new_path) int Process::sys$link(const Syscall::SC_link_params* user_params)
{ {
SmapDisabler disabler; if (!validate_read_typed(user_params))
if (!validate_read_str(old_path))
return -EFAULT; return -EFAULT;
if (!validate_read_str(new_path)) Syscall::SC_link_params params;
copy_from_user(&params, user_params, sizeof(params));
auto old_path = validate_and_copy_string_from_user(params.old_path);
auto new_path = validate_and_copy_string_from_user(params.new_path);
if (old_path.is_null() || new_path.is_null())
return -EFAULT; return -EFAULT;
return VFS::the().link(StringView(old_path), StringView(new_path), current_directory()); return VFS::the().link(old_path, new_path, current_directory());
} }
int Process::sys$unlink(const char* user_path, size_t path_length) int Process::sys$unlink(const char* user_path, size_t path_length)

4
Kernel/Process.h
View file

@ -175,7 +175,7 @@ public:
int sys$mkdir(const char* pathname, size_t path_length, mode_t mode); int sys$mkdir(const char* pathname, size_t path_length, mode_t mode);
clock_t sys$times(tms*); clock_t sys$times(tms*);
int sys$utime(const char* pathname, size_t path_length, const struct utimbuf*); int sys$utime(const char* pathname, size_t path_length, const struct utimbuf*);
int sys$link(const char* old_path, const char* new_path); int sys$link(const Syscall::SC_link_params*);
int sys$unlink(const char* pathname, size_t path_length); int sys$unlink(const char* pathname, size_t path_length);
int sys$symlink(const char* target, const char* linkpath); int sys$symlink(const char* target, const char* linkpath);
int sys$rmdir(const char* pathname, size_t path_length); int sys$rmdir(const char* pathname, size_t path_length);
@ -263,6 +263,8 @@ public:
template<typename DataType, typename SizeType> template<typename DataType, typename SizeType>
bool validate(const Syscall::MutableBufferArgument<DataType, SizeType>&); bool validate(const Syscall::MutableBufferArgument<DataType, SizeType>&);
String validate_and_copy_string_from_user(const Syscall::StringArgument&) const;
Custody& current_directory(); Custody& current_directory();
Custody* executable() { return m_executable.ptr(); } Custody* executable() { return m_executable.ptr(); }

4
Kernel/StdLib.h
View file

@ -6,6 +6,10 @@ namespace AK {
class String; class String;
} }
namespace Syscall {
struct StringArgument;
}
AK::String copy_string_from_user(const char*, size_t); AK::String copy_string_from_user(const char*, size_t);
extern "C" { extern "C" {

5
Kernel/Syscall.h
View file

@ -327,6 +327,11 @@ struct SC_readlink_params {
MutableBufferArgument<char, size_t> buffer; MutableBufferArgument<char, size_t> buffer;
}; };
struct SC_link_params {
StringArgument old_path;
StringArgument new_path;
};
void initialize(); void initialize();
int sync(); int sync();

7
Libraries/LibC/unistd.cpp
View file

@ -339,7 +339,12 @@ off_t lseek(int fd, off_t offset, int whence)
int link(const char* old_path, const char* new_path) int link(const char* old_path, const char* new_path)
{ {
int rc = syscall(SC_link, old_path, new_path); if (!old_path || !new_path) {
errno = EFAULT;
return -1;
}
Syscall::SC_link_params params { { old_path, strlen(old_path) }, { new_path, strlen(new_path) } };
int rc = syscall(SC_link, &params);
__RETURN_WITH_ERRNO(rc, rc, -1); __RETURN_WITH_ERRNO(rc, rc, -1);
} }