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Kernel: Make sys$getsid not require the big lock

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Reorganize the code slightly to avoid creating a TOCTOU bug, then mark
the syscall as not needing the big lock anymore.
This commit is contained in:
Andreas Kling 2023-04-03 13:39:11 +02:00
parent 1382439267
commit 41f5598516
2 changed files with 8 additions and 7 deletions
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2
Kernel/API/Syscall.h
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@ -104,7 +104,7 @@ enum class NeedsBigProcessLock {
S(getresgid, NeedsBigProcessLock::No) \ S(getresgid, NeedsBigProcessLock::No) \
S(getresuid, NeedsBigProcessLock::No) \ S(getresuid, NeedsBigProcessLock::No) \
S(getrusage, NeedsBigProcessLock::Yes) \ S(getrusage, NeedsBigProcessLock::Yes) \
S(getsid, NeedsBigProcessLock::Yes) \ S(getsid, NeedsBigProcessLock::No) \
S(getsockname, NeedsBigProcessLock::Yes) \ S(getsockname, NeedsBigProcessLock::Yes) \
S(getsockopt, NeedsBigProcessLock::No) \ S(getsockopt, NeedsBigProcessLock::No) \
S(gettid, NeedsBigProcessLock::No) \ S(gettid, NeedsBigProcessLock::No) \

13
Kernel/Syscalls/setpgid.cpp
View file

@ -12,16 +12,17 @@ namespace Kernel {
ErrorOr<FlatPtr> Process::sys$getsid(pid_t pid) ErrorOr<FlatPtr> Process::sys$getsid(pid_t pid)
{ {
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this); VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio)); TRY(require_promise(Pledge::stdio));
if (pid == 0) if (pid == 0 || pid == this->pid())
return sid().value(); return sid().value();
auto process = Process::from_pid_in_same_jail(pid); auto peer = Process::from_pid_in_same_jail(pid);
if (!process) if (!peer)
return ESRCH; return ESRCH;
if (sid() != process->sid()) auto peer_sid = peer->sid();
if (sid() != peer_sid)
return EPERM; return EPERM;
return process->sid().value(); return peer_sid.value();
} }
ErrorOr<FlatPtr> Process::sys$setsid() ErrorOr<FlatPtr> Process::sys$setsid()