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Merge tag 'probes-fixes-v6.5-rc3' of git://git.kernel.org/pub/scm/lin…
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…ux/kernel/git/trace/linux-trace

Pull probe fixes from Masami Hiramatsu:

 - probe-events: add NULL check for some BTF API calls which can return
   error code and NULL.

 - ftrace selftests: check fprobe and kprobe event correctly. This fixes
   a miss condition of the test command.

 - kprobes: do not allow probing functions that start with "__cfi_" or
   "__pfx_" since those are auto generated for kernel CFI and not
   executed.

* tag 'probes-fixes-v6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  kprobes: Prohibit probing on CFI preamble symbol
  selftests/ftrace: Fix to check fprobe event eneblement
  tracing/probes: Fix to add NULL check for BTF APIs
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torvalds committed Jul 30, 2023
2 parents 98a05fe + de02f2a commit b0b9850
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Showing 3 changed files with 18 additions and 6 deletions.
14 changes: 13 additions & 1 deletion kernel/kprobes.c
Original file line number Diff line number Diff line change
Expand Up @@ -1545,6 +1545,17 @@ static int check_ftrace_location(struct kprobe *p)
return 0;
}

static bool is_cfi_preamble_symbol(unsigned long addr)
{
char symbuf[KSYM_NAME_LEN];

if (lookup_symbol_name(addr, symbuf))
return false;

return str_has_prefix("__cfi_", symbuf) ||
str_has_prefix("__pfx_", symbuf);
}

static int check_kprobe_address_safe(struct kprobe *p,
struct module **probed_mod)
{
Expand All @@ -1563,7 +1574,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
within_kprobe_blacklist((unsigned long) p->addr) ||
jump_label_text_reserved(p->addr, p->addr) ||
static_call_text_reserved(p->addr, p->addr) ||
find_bug((unsigned long)p->addr)) {
find_bug((unsigned long)p->addr) ||
is_cfi_preamble_symbol((unsigned long)p->addr)) {
ret = -EINVAL;
goto out;
}
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8 changes: 4 additions & 4 deletions kernel/trace/trace_probe.c
Original file line number Diff line number Diff line change
Expand Up @@ -386,12 +386,12 @@ static const struct btf_type *find_btf_func_proto(const char *funcname)

/* Get BTF_KIND_FUNC type */
t = btf_type_by_id(btf, id);
if (!btf_type_is_func(t))
if (!t || !btf_type_is_func(t))
return ERR_PTR(-ENOENT);

/* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
t = btf_type_by_id(btf, t->type);
if (!btf_type_is_func_proto(t))
if (!t || !btf_type_is_func_proto(t))
return ERR_PTR(-ENOENT);

return t;
Expand Down Expand Up @@ -443,7 +443,7 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code,
if (!ctx->params) {
params = find_btf_func_param(ctx->funcname, &ctx->nr_params,
ctx->flags & TPARG_FL_TPOINT);
if (IS_ERR(params)) {
if (IS_ERR_OR_NULL(params)) {
trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
return PTR_ERR(params);
}
Expand Down Expand Up @@ -1273,7 +1273,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],

params = find_btf_func_param(ctx->funcname, &nr_params,
ctx->flags & TPARG_FL_TPOINT);
if (IS_ERR(params)) {
if (IS_ERR_OR_NULL(params)) {
if (args_idx != -1) {
/* $arg* requires BTF info */
trace_probe_log_err(0, NOSUP_BTFARG);
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ if grep -qF "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README ; the
FPROBES=yes
fi

if [ -z "$KPROBES" -a "$FPROBES" ] ; then
if [ -z "$KPROBES" -a -z "$FPROBES" ] ; then
exit_unsupported
fi

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