Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
rseq: Replace the original debug implementation
Just utilize the new infrastructure and put the original one to rest.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.212510692@linutronix.de
authored by
Thomas Gleixner
and committed by
Ingo Molnar
f7ee1964
abc850e7
+12
-69
+12
-69
kernel/rseq.c
+12
-69
kernel/rseq.c
···
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#ifdef CONFIG_DEBUG_RSEQ
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/*
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* Unsigned comparison will be true when ip >= start_ip, and when
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* ip < start_ip + post_commit_offset.
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*/
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static bool in_rseq_cs(unsigned long ip, struct rseq_cs *rseq_cs)
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{
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return ip - rseq_cs->start_ip < rseq_cs->post_commit_offset;
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}
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-
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/*
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* If the rseq_cs field of 'struct rseq' contains a valid pointer to
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* user-space, copy 'struct rseq_cs' from user-space and validate its fields.
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*/
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static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
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{
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struct rseq __user *urseq = t->rseq.usrptr;
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struct rseq_cs __user *urseq_cs;
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u32 __user *usig;
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u64 ptr;
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u32 sig;
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int ret;
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-
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if (get_user(ptr, &rseq->rseq_cs))
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return -EFAULT;
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-
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/* If the rseq_cs pointer is NULL, return a cleared struct rseq_cs. */
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if (!ptr) {
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memset(rseq_cs, 0, sizeof(*rseq_cs));
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return 0;
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}
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/* Check that the pointer value fits in the user-space process space. */
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if (ptr >= TASK_SIZE)
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return -EINVAL;
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urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr;
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if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
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return -EFAULT;
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-
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if (rseq_cs->start_ip >= TASK_SIZE ||
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rseq_cs->start_ip + rseq_cs->post_commit_offset >= TASK_SIZE ||
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rseq_cs->abort_ip >= TASK_SIZE ||
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rseq_cs->version > 0)
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return -EINVAL;
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/* Check for overflow. */
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if (rseq_cs->start_ip + rseq_cs->post_commit_offset < rseq_cs->start_ip)
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return -EINVAL;
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/* Ensure that abort_ip is not in the critical section. */
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if (rseq_cs->abort_ip - rseq_cs->start_ip < rseq_cs->post_commit_offset)
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return -EINVAL;
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-
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usig = (u32 __user *)(unsigned long)(rseq_cs->abort_ip - sizeof(u32));
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ret = get_user(sig, usig);
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if (ret)
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return ret;
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if (current->rseq.sig != sig) {
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printk_ratelimited(KERN_WARNING
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"Possible attack attempt. Unexpected rseq signature 0x%x, expecting 0x%x (pid=%d, addr=%p).\n",
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sig, current->rseq.sig, current->pid, usig);
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return -EINVAL;
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}
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return 0;
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}
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-
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/*
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* Terminate the process if a syscall is issued within a restartable
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* sequence.
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*/
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void rseq_syscall(struct pt_regs *regs)
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{
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unsigned long ip = instruction_pointer(regs);
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struct task_struct *t = current;
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struct rseq_cs rseq_cs;
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u64 csaddr;
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if (!t->rseq.usrptr)
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if (!t->rseq.event.has_rseq)
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return;
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if (rseq_get_rseq_cs(t, &rseq_cs) || in_rseq_cs(ip, &rseq_cs))
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force_sig(SIGSEGV);
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if (get_user(csaddr, &t->rseq.usrptr->rseq_cs))
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goto fail;
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if (likely(!csaddr))
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return;
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if (unlikely(csaddr >= TASK_SIZE))
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goto fail;
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if (rseq_debug_update_user_cs(t, regs, csaddr))
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return;
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fail:
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force_sig(SIGSEGV);
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}
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-
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#endif
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/*