bpf: handle the compat string in bpf_trace_copy_string better

User the proper helper for kernel or userspace addresses based on TASK_SIZE instead of the dangerous strncpy_from_unsafe function.

Christoph Hellwig committed 6 years ago

Commit aec6ce51 parent d7b29771 file · +5 −2Browse files

Showing the changes to kernel (1 of 1 file). Show all

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@@ -334,8 +334,11 @@ static void bpf_trace_copy_string(char buf, void unsafe_ptr, char fmt_ptype, · 333 unmodified lines
334	334	switch (fmt_ptype) {
335	335	case 's':
336	336	#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
337		− strncpy_from_unsafe(buf, unsafe_ptr, bufsz);
338		− break;
	337	+ if ((unsigned long)unsafe_ptr < TASK_SIZE) {
	338	+ strncpy_from_user_nofault(buf, user_ptr, bufsz);
	339	+ break;
	340	+ }
	341	+ fallthrough;
339	342	#endif
340	343	case 'k':
341	344	strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);

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