From: Masami Hiramatsu (Google) mhiramat@kernel.org
[ Upstream commit 797311bce5c2ac90b8d65e357603cfd410d36ebb ]
Fix to record 0-length data to data_loc in fetch_store_string*() if it fails to get the string data. Currently those expect that the data_loc is updated by store_trace_args() if it returns the error code. However, that does not work correctly if the argument is an array of strings. In that case, store_trace_args() only clears the first entry of the array (which may have no error) and leaves other entries. So it should be cleared by fetch_store_string*() itself. Also, 'dyndata' and 'maxlen' in store_trace_args() should be updated only if it is used (ret > 0 and argument is a dynamic data.)
Link: https://lore.kernel.org/all/168908496683.123124.4761206188794205601.stgit@de...
Fixes: 40b53b771806 ("tracing: probeevent: Add array type support") Cc: stable@vger.kernel.org Reviewed-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/trace_probe_kernel.h | 13 +++++++++---- kernel/trace/trace_probe_tmpl.h | 10 +++------- kernel/trace/trace_uprobe.c | 3 ++- 3 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h index 1d43df29a1f8e..2da70be83831c 100644 --- a/kernel/trace/trace_probe_kernel.h +++ b/kernel/trace/trace_probe_kernel.h @@ -37,6 +37,13 @@ kern_fetch_store_strlen(unsigned long addr) return (ret < 0) ? ret : len; }
+static nokprobe_inline void set_data_loc(int ret, void *dest, void *__dest, void *base) +{ + if (ret < 0) + ret = 0; + *(u32 *)dest = make_data_loc(ret, __dest - base); +} + /* * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf * with max length and relative data location. @@ -55,8 +62,7 @@ kern_fetch_store_string_user(unsigned long addr, void *dest, void *base) __dest = get_loc_data(dest, base);
ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); + set_data_loc(ret, dest, __dest, base);
return ret; } @@ -87,8 +93,7 @@ kern_fetch_store_string(unsigned long addr, void *dest, void *base) * probing. */ ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); + set_data_loc(ret, dest, __dest, base);
return ret; } diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 98ac09052fea4..3e2f5a43b974c 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -247,13 +247,9 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec, if (unlikely(arg->dynamic)) *dl = make_data_loc(maxlen, dyndata - base); ret = process_fetch_insn(arg->code, rec, dl, base); - if (arg->dynamic) { - if (unlikely(ret < 0)) { - *dl = make_data_loc(0, dyndata - base); - } else { - dyndata += ret; - maxlen -= ret; - } + if (arg->dynamic && likely(ret > 0)) { + dyndata += ret; + maxlen -= ret; } } } diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 78ec1c16ccf4b..debc651015489 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -168,7 +168,8 @@ fetch_store_string(unsigned long addr, void *dest, void *base) */ ret++; *(u32 *)dest = make_data_loc(ret, (void *)dst - base); - } + } else + *(u32 *)dest = make_data_loc(0, (void *)dst - base);
return ret; }