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Message-Id: <166679931679.1528100.15540755370726009882.stgit@devnote3>
Date: Thu, 27 Oct 2022 00:48:36 +0900
From: "Masami Hiramatsu (Google)" <mhiramat@...nel.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Linux Trace Kernel <linux-trace-kernel@...r.kernel.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Primiano Tucci <primiano@...gle.com>
Subject: [PATCH v2 2/2] tracing/probes: Reject symbol/symstr type for uprobe
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Since uprobe's argument must contain the user-space data, that
should not be converted to kernel symbols. Reject if user
specifies these types on uprobe events. e.g.
/sys/kernel/debug/tracing # echo 'p /bin/sh:10 %ax:symbol' >> uprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # echo 'p /bin/sh:10 %ax:symstr' >> uprobe_events
sh: write error: Invalid argument
/sys/kernel/debug/tracing # cat error_log
[ 1783.134883] trace_uprobe: error: Unknown type is specified
Command: p /bin/sh:10 %ax:symbol
^
[ 1792.201120] trace_uprobe: error: Unknown type is specified
Command: p /bin/sh:10 %ax:symstr
^
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
---
Changes in v2:
- Fixes indentation.
---
kernel/trace/trace_probe.c | 21 ++++++++++++--------
kernel/trace/trace_probe.h | 3 ++-
kernel/trace/trace_uprobe.c | 3 ++-
.../ftrace/test.d/kprobe/uprobe_syntax_errors.tc | 5 +++++
4 files changed, 22 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index dfec4af857b4..960bb7693a84 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -100,10 +100,15 @@ static const struct fetch_type probe_fetch_types[] = {
ASSIGN_FETCH_TYPE_END
};
-static const struct fetch_type *find_fetch_type(const char *type)
+static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
{
int i;
+ /* Reject the symbol/symstr for uprobes */
+ if (type && (flags & TPARG_FL_USER) &&
+ (!strcmp(type, "symbol") || !strcmp(type, "symstr")))
+ return NULL;
+
if (!type)
type = DEFAULT_FETCH_TYPE_STR;
@@ -121,13 +126,13 @@ static const struct fetch_type *find_fetch_type(const char *type)
switch (bs) {
case 8:
- return find_fetch_type("u8");
+ return find_fetch_type("u8", flags);
case 16:
- return find_fetch_type("u16");
+ return find_fetch_type("u16", flags);
case 32:
- return find_fetch_type("u32");
+ return find_fetch_type("u32", flags);
case 64:
- return find_fetch_type("u64");
+ return find_fetch_type("u64", flags);
default:
goto fail;
}
@@ -480,7 +485,7 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
DEREF_OPEN_BRACE);
return -EINVAL;
} else {
- const struct fetch_type *t2 = find_fetch_type(NULL);
+ const struct fetch_type *t2 = find_fetch_type(NULL, flags);
*tmp = '\0';
ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
@@ -632,9 +637,9 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
/* The type of $comm must be "string", and not an array. */
if (parg->count || (t && strcmp(t, "string")))
goto out;
- parg->type = find_fetch_type("string");
+ parg->type = find_fetch_type("string", flags);
} else
- parg->type = find_fetch_type(t);
+ parg->type = find_fetch_type(t, flags);
if (!parg->type) {
trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
goto out;
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 0838b74f403b..23acfd1c3812 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -358,7 +358,8 @@ int trace_probe_create(const char *raw_command, int (*createfn)(int, const char
#define TPARG_FL_KERNEL BIT(1)
#define TPARG_FL_FENTRY BIT(2)
#define TPARG_FL_TPOINT BIT(3)
-#define TPARG_FL_MASK GENMASK(3, 0)
+#define TPARG_FL_USER BIT(4)
+#define TPARG_FL_MASK GENMASK(4, 0)
extern int traceprobe_parse_probe_arg(struct trace_probe *tp, int i,
const char *argv, unsigned int flags);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index fb58e86dd117..8d64b6553aed 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -691,7 +691,8 @@ static int __trace_uprobe_create(int argc, const char **argv)
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
trace_probe_log_set_index(i + 2);
ret = traceprobe_parse_probe_arg(&tu->tp, i, argv[i],
- is_return ? TPARG_FL_RETURN : 0);
+ (is_return ? TPARG_FL_RETURN : 0) |
+ TPARG_FL_USER);
if (ret)
goto error;
}
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
index f5e3f9e4a01f..c817158b99db 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
@@ -23,4 +23,9 @@ check_error 'p /bin/sh:10^%hoge' # BAD_ADDR_SUFFIX
check_error 'p /bin/sh:10(10)^%return' # BAD_REFCNT_SUFFIX
fi
+# symstr is not supported by uprobe
+if grep -q ".*symstr.*" README; then
+check_error 'p /bin/sh:10 $stack0:^symstr' # BAD_TYPE
+fi
+
exit 0
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