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kernel: Mask away unsafe bits in rflags when restoring state after a signal
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apio 2023-07-15 11:54:48 +02:00
parent 89786d8be2
commit f9003d7a58
Signed by: apio
GPG Key ID: B8A7D06E42258954
1 changed files with 3 additions and 2 deletions
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5
kernel/src/arch/x86_64/Thread.cpp
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@ -150,6 +150,8 @@ void Thread::sigreturn(Registers* current_regs)
{ {
memcpy(&regs, current_regs, sizeof(regs)); memcpy(&regs, current_regs, sizeof(regs));
u64 rflags = current_regs->rflags;
u64 rsp; u64 rsp;
pop_mem_from_stack((u8*)&rsp, sizeof(rsp)); pop_mem_from_stack((u8*)&rsp, sizeof(rsp));
regs.rsp = rsp; regs.rsp = rsp;
@ -159,8 +161,7 @@ void Thread::sigreturn(Registers* current_regs)
memcpy(&regs, current_regs, sizeof(regs)); memcpy(&regs, current_regs, sizeof(regs));
regs.cs = 0x18 | 3; regs.cs = 0x18 | 3;
regs.ss = 0x20 | 3; regs.ss = 0x20 | 3;
// FIXME: Using this, a program can craft a special RFLAGS that gives them a higher IOPL or other stuff. Find out regs.rflags = (rflags & ~0xdff) | (regs.rflags & 0xdff);
// exactly what bits to block from modifying.
fp_data.restore(); fp_data.restore();