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Kernel: Migrate sys$pledge to use the KString API

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This avoids potential unhandled OOM that's possible with the old
copy_string_from_user API.
This commit is contained in:
Brian Gianforcaro 2021-07-23 09:14:35 -07:00 • committed by Andreas Kling
parent 8acbe03342
commit 36ff717c54
1 changed files with 15 additions and 14 deletions
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29
Kernel/Syscalls/pledge.cpp
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@ -19,21 +19,23 @@ KResultOr<FlatPtr> Process::sys$pledge(Userspace<const Syscall::SC_pledge_params
if (params.promises.length > 1024 || params.execpromises.length > 1024) if (params.promises.length > 1024 || params.execpromises.length > 1024)
return E2BIG; return E2BIG;
String promises; OwnPtr<KString> promises;
if (params.promises.characters) { if (params.promises.characters) {
promises = copy_string_from_user(params.promises); auto promises_or_error = try_copy_kstring_from_user(params.promises);
if (promises.is_null()) if (promises_or_error.is_error())
return EFAULT; return promises_or_error.error();
promises = promises_or_error.release_value();
} }
String execpromises; OwnPtr<KString> execpromises;
if (params.execpromises.characters) { if (params.execpromises.characters) {
execpromises = copy_string_from_user(params.execpromises); auto execpromises_or_error = try_copy_kstring_from_user(params.execpromises);
if (execpromises.is_null()) if (execpromises_or_error.is_error())
return EFAULT; return execpromises_or_error.error();
execpromises = execpromises_or_error.release_value();
} }
auto parse_pledge = [&](auto& pledge_spec, u32& mask) { auto parse_pledge = [&](auto pledge_spec, u32& mask) {
auto parts = pledge_spec.split_view(' '); auto parts = pledge_spec.split_view(' ');
for (auto& part : parts) { for (auto& part : parts) {
#define __ENUMERATE_PLEDGE_PROMISE(x) \ #define __ENUMERATE_PLEDGE_PROMISE(x) \
@ -50,20 +52,19 @@ KResultOr<FlatPtr> Process::sys$pledge(Userspace<const Syscall::SC_pledge_params
ProtectedDataMutationScope scope { *this }; ProtectedDataMutationScope scope { *this };
if (!promises.is_null()) { if (promises) {
u32 new_promises = 0; u32 new_promises = 0;
if (!parse_pledge(promises, new_promises)) if (!parse_pledge(promises->view(), new_promises))
return EINVAL; return EINVAL;
if (m_has_promises && (new_promises & ~m_promises)) if (m_has_promises && (new_promises & ~m_promises))
return EPERM; return EPERM;
m_has_promises = true; m_has_promises = true;
m_promises = new_promises; m_promises = new_promises;
} }
if (!execpromises.is_null()) { if (execpromises) {
u32 new_execpromises = 0; u32 new_execpromises = 0;
if (!parse_pledge(execpromises, new_execpromises)) if (!parse_pledge(execpromises->view(), new_execpromises))
return EINVAL; return EINVAL;
if (m_has_execpromises && (new_execpromises & ~m_execpromises)) if (m_has_execpromises && (new_execpromises & ~m_execpromises))
return EPERM; return EPERM;