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bpftool: Fix UAF in get_delegate_value

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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: 2d812311c2 ("bpftool: Add bpf_token show")
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20250919034816.1287280-2-chen.dylane@linux.dev
This commit is contained in:
Tao Chen 2025-09-19 11:48:16 +08:00 • committed by Andrii Nakryiko
parent bce5749b02
commit 57cb269501
1 changed files with 37 additions and 53 deletions
Download patch file Download diff file Expand all files Collapse all files

90
tools/bpf/bpftool/token.c
View file

@ -20,6 +20,16 @@
#define MOUNTS_FILE "/proc/mounts"
static 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 +73,31 @@ 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;
size_t i;
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);
for (i = 0; i < ARRAY_SIZE(sets); i++) {
char *opts, *value;
printf("\n\tallowed_maps:");
value = get_delegate_value(mntent->mnt_opts, "delegate_maps");
print_items_per_line(value, ITEMS_PER_LINE);
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_progs:");
value = get_delegate_value(mntent->mnt_opts, "delegate_progs");
print_items_per_line(value, ITEMS_PER_LINE);
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 +105,30 @@ 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;
size_t i;
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);
for (i = 0; i < ARRAY_SIZE(sets); i++) {
char *opts, *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);
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);
}