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authorChristoph Hellwig <hch@lst.de>2020-06-08 21:34:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:15 -0700
commitd7b2977b816223a884814eea46fbe38e192cec4c (patch)
tree98f94ef406f5567e78a3e2df7216dd7b20eb531d /kernel
parenteab0c6089b68974ebc6a9a7eab68456eeb6a99c7 (diff)
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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: 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/20200521152301.2587579-12-hch@lst.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/bpf_trace.c42
1 files changed, 24 insertions, 18 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 879ee676bf5a..60e82c7b8122 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -324,6 +324,28 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
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:
* %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s
@@ -406,24 +428,8 @@ fmt_str:
break;
}
- buf[0] = 0;
- switch (fmt_ptype) {
- 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;
- }
+ bpf_trace_copy_string(buf, unsafe_ptr, fmt_ptype,
+ sizeof(buf));
goto fmt_next;
}