[PATCH 2/2] tracing/probes: Reject symbol/symstr type for uprobe
From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: 2022-10-22 06:39:13
Also in:
lkml
Subsystem:
kernel selftest framework, the rest, tracing · Maintainers:
Shuah Khan, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: Masami Hiramatsu (Google) <mhiramat@kernel.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@kernel.org>
---
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..e63ac6453f5c 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