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Message-ID: <20250918120908.1255263-2-chen.dylane@linux.dev>
Date: Thu, 18 Sep 2025 20:09:08 +0800
From: Tao Chen <chen.dylane@...ux.dev>
To: qmo@...nel.org,
ast@...nel.org,
daniel@...earbox.net,
andrii@...nel.org,
martin.lau@...ux.dev,
eddyz87@...il.com,
song@...nel.org,
yonghong.song@...ux.dev,
john.fastabend@...il.com,
kpsingh@...nel.org,
sdf@...ichev.me,
haoluo@...gle.com,
jolsa@...nel.org,
chen.dylane@...ux.dev
Cc: bpf@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next v3 2/2] bpftool: Fix UAF in get_delegate_value
The return value ret pointer is pointing opts_copy, but opts_copy
gets freed in get_delegate_value before return, fix this by free
the mntent->mnt_opts strdup memory after show delegate value.
Fixes: 2d812311c2b2 ("bpftool: Add bpf_token show")
Signed-off-by: Tao Chen <chen.dylane@...ux.dev>
---
tools/bpf/bpftool/token.c | 90 +++++++++++++++------------------------
1 file changed, 35 insertions(+), 55 deletions(-)
diff --git a/tools/bpf/bpftool/token.c b/tools/bpf/bpftool/token.c
index 82b829e44c8..20c4c78a8a8 100644
--- a/tools/bpf/bpftool/token.c
+++ b/tools/bpf/bpftool/token.c
@@ -20,6 +20,16 @@
#define MOUNTS_FILE "/proc/mounts"
+struct {
+ const char *header;
+ const char *key;
+} sets[] = {
+ {"allowed_cmds", "delegate_cmds"},
+ {"allowed_maps", "delegate_maps"},
+ {"allowed_progs", "delegate_progs"},
+ {"allowed_attachs", "delegate_attachs"},
+};
+
static bool has_delegate_options(const char *mnt_ops)
{
return strstr(mnt_ops, "delegate_cmds") ||
@@ -28,15 +38,14 @@ static bool has_delegate_options(const char *mnt_ops)
strstr(mnt_ops, "delegate_attachs");
}
-static char *get_delegate_value(const char *opts, const char *key)
+static char *get_delegate_value(char *opts, const char *key)
{
char *token, *rest, *ret = NULL;
- char *opts_copy = strdup(opts);
- if (!opts_copy)
+ if (!opts)
return NULL;
- for (token = strtok_r(opts_copy, ",", &rest); token;
+ for (token = strtok_r(opts, ",", &rest); token;
token = strtok_r(NULL, ",", &rest)) {
if (strncmp(token, key, strlen(key)) == 0 &&
token[strlen(key)] == '=') {
@@ -44,24 +53,19 @@ static char *get_delegate_value(const char *opts, const char *key)
break;
}
}
- free(opts_copy);
return ret;
}
-static void print_items_per_line(const char *input, int items_per_line)
+static void print_items_per_line(char *input, int items_per_line)
{
- char *str, *rest, *strs;
+ char *str, *rest;
int cnt = 0;
if (!input)
return;
- strs = strdup(input);
- if (!strs)
- return;
-
- for (str = strtok_r(strs, ":", &rest); str;
+ for (str = strtok_r(input, ":", &rest); str;
str = strtok_r(NULL, ":", &rest)) {
if (cnt % items_per_line == 0)
printf("\n\t ");
@@ -69,38 +73,29 @@ static void print_items_per_line(const char *input, int items_per_line)
printf("%-20s", str);
cnt++;
}
-
- free(strs);
}
#define ITEMS_PER_LINE 4
static void show_token_info_plain(struct mntent *mntent)
{
- char *value;
+ char *opts, *value;
printf("token_info %s", mntent->mnt_dir);
- printf("\n\tallowed_cmds:");
- value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
- print_items_per_line(value, ITEMS_PER_LINE);
-
- printf("\n\tallowed_maps:");
- value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
- print_items_per_line(value, ITEMS_PER_LINE);
-
- printf("\n\tallowed_progs:");
- value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
- print_items_per_line(value, ITEMS_PER_LINE);
+ for (size_t i = 0; i < ARRAY_SIZE(sets); i++) {
+ printf("\n\t%s:", sets[i].header);
+ opts = strdup(mntent->mnt_opts);
+ value = get_delegate_value(opts, sets[i].key);
+ print_items_per_line(value, ITEMS_PER_LINE);
+ free(opts);
+ }
- printf("\n\tallowed_attachs:");
- value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
- print_items_per_line(value, ITEMS_PER_LINE);
printf("\n");
}
-static void split_json_array_str(const char *input)
+static void split_json_array_str(char *input)
{
- char *str, *rest, *strs;
+ char *str, *rest;
if (!input) {
jsonw_start_array(json_wtr);
@@ -108,43 +103,28 @@ static void split_json_array_str(const char *input)
return;
}
- strs = strdup(input);
- if (!strs)
- return;
-
jsonw_start_array(json_wtr);
- for (str = strtok_r(strs, ":", &rest); str;
+ for (str = strtok_r(input, ":", &rest); str;
str = strtok_r(NULL, ":", &rest)) {
jsonw_string(json_wtr, str);
}
jsonw_end_array(json_wtr);
-
- free(strs);
}
static void show_token_info_json(struct mntent *mntent)
{
- char *value;
+ char *opts, *value;
jsonw_start_object(json_wtr);
-
jsonw_string_field(json_wtr, "token_info", mntent->mnt_dir);
- jsonw_name(json_wtr, "allowed_cmds");
- value = get_delegate_value(mntent->mnt_opts, "delegate_cmds");
- split_json_array_str(value);
-
- jsonw_name(json_wtr, "allowed_maps");
- value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
- split_json_array_str(value);
-
- jsonw_name(json_wtr, "allowed_progs");
- value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
- split_json_array_str(value);
-
- jsonw_name(json_wtr, "allowed_attachs");
- value = get_delegate_value(mntent->mnt_opts, "delegate_attachs");
- split_json_array_str(value);
+ for (size_t i = 0; i < ARRAY_SIZE(sets); i++) {
+ jsonw_name(json_wtr, sets[i].header);
+ opts = strdup(mntent->mnt_opts);
+ value = get_delegate_value(opts, sets[i].key);
+ split_json_array_str(value);
+ free(opts);
+ }
jsonw_end_object(json_wtr);
}
--
2.48.1
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