[PATCH v3 12/13] tracing/probes: Validate command prefix in kprobe, uprobe, and eprobe

["Masami Hiramatsu (Google)" <mhiramat@kernel.org>]

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

In kprobe, uprobe, and eprobe creation, trailing characters after the
command prefix ('p', 'r', or 'e') without a ':' separator (or non-digit
characters before ':') are silently ignored, creating a probe with the
default event name instead of reporting a syntax error as fprobe does.

Reject invalid characters following the command prefix with BAD_MAXACT.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 kernel/trace/trace_eprobe.c |   10 ++++++++--
 kernel/trace/trace_kprobe.c |    3 +++
 kernel/trace/trace_uprobe.c |   12 +++++++++---
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index f65393fb1c10..f65da7b3adf4 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -846,12 +846,18 @@ static int __trace_eprobe_create(int argc, const char *argv[])
 
 	trlog = trace_probe_log_init("event_probe", argc, argv);
 
-	event = strchr(&argv[0][1], ':');
+	if (argv[0][1] != '\0') {
+		if (argv[0][1] != ':') {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(1, BAD_MAXACT);
+			return -EINVAL;
+		}
+		event = &argv[0][2];
+	}
 	if (event) {
 		gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
 		if (!gbuf)
 			return -ENOMEM;
-		event++;
 		ret = traceprobe_parse_event_name(&event, &group, gbuf,
 						  event - argv[0]);
 		if (ret)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a42af0e66009..35568d75723c 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -941,6 +941,9 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
 			trace_probe_log_err(1, MAXACT_TOO_BIG);
 			return -EINVAL;
 		}
+	} else if (argv[0][1] != '\0' && argv[0][1] != ':') {
+		trace_probe_log_err(1, BAD_MAXACT);
+		return -EINVAL;
 	}
 
 	/* try to parse an address. if that fails, try to read the
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index fb7991543db7..9f8f81a36192 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -616,9 +616,6 @@ static int __trace_uprobe_create(int argc, const char **argv)
 		return -E2BIG;
 	}
 
-	if (argv[0][1] == ':')
-		event = &argv[0][2];
-
 	if (!strchr(argv[1], '/'))
 		return -ECANCELED;
 
@@ -631,6 +628,15 @@ static int __trace_uprobe_create(int argc, const char **argv)
 	if (!arg || !isdigit(arg[1]))
 		return -ECANCELED;
 
+	if (argv[0][1] != '\0') {
+		if (argv[0][1] != ':') {
+			trace_probe_log_set_index(0);
+			trace_probe_log_err(1, BAD_MAXACT);
+			return -EINVAL;
+		}
+		event = &argv[0][2];
+	}
+
 	trace_probe_log_set_index(1);	/* filename is the 2nd argument */
 
 	*arg++ = '\0';