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bpf: handle the compat string in bpf_trace_copy_string better

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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>
This commit is contained in:
Christoph Hellwig 2020-06-08 21:34:33 -07:00 committed by Linus Torvalds
parent d7b2977b81
commit aec6ce5913
1 changed files with 5 additions and 2 deletions
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7
kernel/trace/bpf_trace.c
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@ -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);
break;
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);