Commit aec6ce59 authored Jun 08, 2020 by Christoph Hellwig Committed by Linus Torvalds Jun 09, 2020

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-13-hch@lst.de

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d7b2977b

kernel/trace/bpf_trace.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -334,8 +334,11 @@ static void bpf_trace_copy_string(char buf, void unsafe_ptr, char fmt_ptype,
		switch (fmt_ptype) {
		case 's':
		#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
		strncpy_from_unsafe(buf, unsafe_ptr, bufsz);
		if ((unsigned long)unsafe_ptr < TASK_SIZE) {
		strncpy_from_user_nofault(buf, user_ptr, bufsz);
		break;
		}
		fallthrough;
		#endif
		case 'k':
		strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);

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