Commit d7b2977b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds

bpf: factor out a bpf_trace_copy_string helper

Split out a helper to do the fault free access to the string pointer
to get it out of a crazy indentation level.
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew 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/20200521152301.2587579-12-hch@lst.deSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent eab0c608
...@@ -324,6 +324,28 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void) ...@@ -324,6 +324,28 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
return &bpf_probe_write_user_proto; return &bpf_probe_write_user_proto;
} }
static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype,
size_t bufsz)
{
void __user *user_ptr = (__force void __user *)unsafe_ptr;
buf[0] = 0;
switch (fmt_ptype) {
case 's':
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
strncpy_from_unsafe(buf, unsafe_ptr, bufsz);
break;
#endif
case 'k':
strncpy_from_kernel_nofault(buf, unsafe_ptr, bufsz);
break;
case 'u':
strncpy_from_user_nofault(buf, user_ptr, bufsz);
break;
}
}
/* /*
* Only limited trace_printk() conversion specifiers allowed: * Only limited trace_printk() conversion specifiers allowed:
* %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s
...@@ -406,24 +428,8 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, ...@@ -406,24 +428,8 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
break; break;
} }
buf[0] = 0; bpf_trace_copy_string(buf, unsafe_ptr, fmt_ptype,
switch (fmt_ptype) { sizeof(buf));
case 's':
#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
strncpy_from_unsafe(buf, unsafe_ptr,
sizeof(buf));
break;
#endif
case 'k':
strncpy_from_kernel_nofault(buf, unsafe_ptr,
sizeof(buf));
break;
case 'u':
strncpy_from_user_nofault(buf,
(__force void __user *)unsafe_ptr,
sizeof(buf));
break;
}
goto fmt_next; goto fmt_next;
} }
......
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