Re: [PATCH v2] ptrace: add PTRACE_GET_RSEQ_CONFIGURATION request
From: Mathieu Desnoyers
Date: Fri Feb 26 2021 - 10:34:43 EST
----- On Feb 26, 2021, at 8:51 AM, Piotr Figiel figiel@xxxxxxxxxx wrote:
[...]
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---
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v2:
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Applied review comments:
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- changed return value from the ptrace request to the size of the
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configuration structure
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- expanded configuration structure with the flags field and
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the rseq abi structure size
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[...]
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+#define PTRACE_GET_RSEQ_CONFIGURATION 0x420f
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+
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+struct ptrace_rseq_configuration {
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+ __u64 rseq_abi_pointer;
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+ __u32 rseq_abi_size;
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+ __u32 signature;
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+ __u32 flags;
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+ __u32 pad;
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+};
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+
[...]
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+#ifdef CONFIG_RSEQ
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+static long ptrace_get_rseq_configuration(struct task_struct *task,
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+ unsigned long size, void __user *data)
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+{
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+ struct ptrace_rseq_configuration conf = {
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+ .rseq_abi_pointer = (u64)(uintptr_t)task->rseq,
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+ .rseq_abi_size = sizeof(*task->rseq),
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+ .signature = task->rseq_sig,
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+ .flags = 0,
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+ };
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+
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+ size = min_t(unsigned long, size, sizeof(conf));
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+ if (copy_to_user(data, &conf, size))
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+ return -EFAULT;
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+ return sizeof(conf);
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+}
I think what Florian was after would be:
struct ptrace_rseq_configuration {
__u32 size; /* size of struct ptrace_rseq_configuration */
__u32 flags;
__u64 rseq_abi_pointer;
__u32 signature;
__u32 pad;
};
where:
.size = sizeof(struct ptrace_rseq_configuration),
This way, the configuration structure can be expanded in the future. The
rseq ABI structure is by definition fixed-size, so there is no point in
having its size here.
Florian, did I understand your request correctly, or am I missing your point ?
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com