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rseq: Replace the original debug implementation

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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
This commit is contained in:
Thomas Gleixner
2025-10-27 09:45:00 +01:00
committed by Ingo Molnar
parent abc850e761
commit f7ee1964ac
1 changed files with 12 additions and 69 deletions
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81
kernel/rseq.c
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@@ -474,85 +474,28 @@ error:
}
#ifdef CONFIG_DEBUG_RSEQ
/*
* Unsigned comparison will be true when ip >= start_ip, and when
* ip < start_ip + post_commit_offset.
*/
static bool in_rseq_cs(unsigned long ip, struct rseq_cs *rseq_cs)
{
return ip - rseq_cs->start_ip < rseq_cs->post_commit_offset;
}
/*
* If the rseq_cs field of 'struct rseq' contains a valid pointer to
* user-space, copy 'struct rseq_cs' from user-space and validate its fields.
*/
static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
{
struct rseq __user *urseq = t->rseq.usrptr;
struct rseq_cs __user *urseq_cs;
u32 __user *usig;
u64 ptr;
u32 sig;
int ret;
if (get_user(ptr, &rseq->rseq_cs))
return -EFAULT;
/* If the rseq_cs pointer is NULL, return a cleared struct rseq_cs. */
if (!ptr) {
memset(rseq_cs, 0, sizeof(*rseq_cs));
return 0;
}
/* Check that the pointer value fits in the user-space process space. */
if (ptr >= TASK_SIZE)
return -EINVAL;
urseq_cs = (struct rseq_cs __user *)(unsigned long)ptr;
if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
return -EFAULT;
if (rseq_cs->start_ip >= TASK_SIZE ||
rseq_cs->start_ip + rseq_cs->post_commit_offset >= TASK_SIZE ||
rseq_cs->abort_ip >= TASK_SIZE ||
rseq_cs->version > 0)
return -EINVAL;
/* Check for overflow. */
if (rseq_cs->start_ip + rseq_cs->post_commit_offset < rseq_cs->start_ip)
return -EINVAL;
/* Ensure that abort_ip is not in the critical section. */
if (rseq_cs->abort_ip - rseq_cs->start_ip < rseq_cs->post_commit_offset)
return -EINVAL;
usig = (u32 __user *)(unsigned long)(rseq_cs->abort_ip - sizeof(u32));
ret = get_user(sig, usig);
if (ret)
return ret;
if (current->rseq.sig != sig) {
printk_ratelimited(KERN_WARNING
"Possible attack attempt. Unexpected rseq signature 0x%x, expecting 0x%x (pid=%d, addr=%p).\n",
sig, current->rseq.sig, current->pid, usig);
return -EINVAL;
}
return 0;
}
/*
* Terminate the process if a syscall is issued within a restartable
* sequence.
*/
void rseq_syscall(struct pt_regs *regs)
{
unsigned long ip = instruction_pointer(regs);
struct task_struct *t = current;
struct rseq_cs rseq_cs;
u64 csaddr;
if (!t->rseq.usrptr)
if (!t->rseq.event.has_rseq)
return;
if (rseq_get_rseq_cs(t, &rseq_cs) || in_rseq_cs(ip, &rseq_cs))
force_sig(SIGSEGV);
if (get_user(csaddr, &t->rseq.usrptr->rseq_cs))
goto fail;
if (likely(!csaddr))
return;
if (unlikely(csaddr >= TASK_SIZE))
goto fail;
if (rseq_debug_update_user_cs(t, regs, csaddr))
return;
fail:
force_sig(SIGSEGV);
}
#endif
/*