diff options
| author |   Christoph Hellwig <hch@lst.de> | 2020-06-08 21:34:30 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-09 09:39:15 -0700 |
| commit | d7b2977b816223a884814eea46fbe38e192cec4c (patch) | |
| tree | 98f94ef406f5567e78a3e2df7216dd7b20eb531d /kernel/trace/bpf_trace.c | |
| parent | maccess: unify the probe kernel arch hooks (diff) | |
| download | linux-dev-d7b2977b816223a884814eea46fbe38e192cec4c.tar.xz linux-dev-d7b2977b816223a884814eea46fbe38e192cec4c.zip | |
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 '')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 42 |
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; } |