bpf: Add name, load_time, uid and map_ids to bpf_prog_info

The patch adds name and load_time to struct bpf_prog_aux.  They
are also exported to bpf_prog_info.

The bpf_prog's name is passed by userspace during BPF_PROG_LOAD.
The kernel only stores the first (BPF_PROG_NAME_LEN - 1) bytes
and the name stored in the kernel is always \0 terminated.

The kernel will reject name that contains characters other than
isalnum() and '_'.  It will also reject name that is not null
terminated.

The existing 'user->uid' of the bpf_prog_aux is also exported to
the bpf_prog_info as created_by_uid.

The existing 'used_maps' of the bpf_prog_aux is exported to
the newly added members 'nr_map_ids' and 'map_ids' of
the bpf_prog_info.  On the input, nr_map_ids tells how
big the userspace's map_ids buffer is.  On the output,
nr_map_ids tells the exact user_map_cnt and it will only
copy up to the userspace's map_ids buffer is allowed.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Alexei Starovoitov <ast@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2b672c50f160e42b1f8f4adf1aa06e930b2b982f..33ccc474fb043a4a9d7eefd33350d79d6f039afc 100644 (file)
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -187,6 +187,8 @@ struct bpf_prog_aux {
        struct bpf_map **used_maps;
        struct bpf_prog *prog;
        struct user_struct *user;
+       u64 load_time; /* ns since boottime */
+       u8 name[BPF_OBJ_NAME_LEN];
        union {
                struct work_struct work;
                struct rcu_head rcu;

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e43491ac4823799ae622ee8a23b139d3970e309a..bd6348269bf548d048348ac58016a74dd963aa09 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -175,6 +175,8 @@ enum bpf_attach_type {
 /* Specify numa node during map creation */
 #define BPF_F_NUMA_NODE                (1U << 2)
 
+#define BPF_OBJ_NAME_LEN 16U
+
 union bpf_attr {
        struct { /* anonymous struct used by BPF_MAP_CREATE command */
                __u32   map_type;       /* one of enum bpf_map_type */
@@ -210,6 +212,7 @@ union bpf_attr {
                __aligned_u64   log_buf;        /* user supplied buffer */
                __u32           kern_version;   /* checked when prog_type=kprobe */
                __u32           prog_flags;
+               __u8            prog_name[BPF_OBJ_NAME_LEN];
        };
 
        struct { /* anonymous struct used by BPF_OBJ_* commands */
@@ -812,6 +815,11 @@ struct bpf_prog_info {
        __u32 xlated_prog_len;
        __aligned_u64 jited_prog_insns;
        __aligned_u64 xlated_prog_insns;
+       __u64 load_time;        /* ns since boottime */
+       __u32 created_by_uid;
+       __u32 nr_map_ids;
+       __aligned_u64 map_ids;
+       __u8  name[BPF_OBJ_NAME_LEN];
 } __attribute__((aligned(8)));
 
 struct bpf_map_info {

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 25d074920a009ff682d97bf88e68f466c79bd564..45970df3f8204e37ccb6b8ccd31a236f3dbf7b99 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -23,6 +23,9 @@
 #include <linux/version.h>
 #include <linux/kernel.h>
 #include <linux/idr.h>
+#include <linux/cred.h>
+#include <linux/timekeeping.h>
+#include <linux/ctype.h>
 
 #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY || \
                           (map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \
@@ -312,6 +315,30 @@ int bpf_map_new_fd(struct bpf_map *map)
                   offsetof(union bpf_attr, CMD##_LAST_FIELD) - \
                   sizeof(attr->CMD##_LAST_FIELD)) != NULL
 
+/* dst and src must have at least BPF_OBJ_NAME_LEN number of bytes.
+ * Return 0 on success and < 0 on error.
+ */
+static int bpf_obj_name_cpy(char *dst, const char *src)
+{
+       const char *end = src + BPF_OBJ_NAME_LEN;
+
+       /* Copy all isalnum() and '_' char */
+       while (src < end && *src) {
+               if (!isalnum(*src) && *src != '_')
+                       return -EINVAL;
+               *dst++ = *src++;
+       }
+
+       /* No '\0' found in BPF_OBJ_NAME_LEN number of bytes */
+       if (src == end)
+               return -EINVAL;
+
+       /* '\0' terminates dst */
+       *dst = 0;
+
+       return 0;
+}
+
 #define BPF_MAP_CREATE_LAST_FIELD numa_node
 /* called via syscall */
 static int map_create(union bpf_attr *attr)
@@ -973,7 +1000,7 @@ struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
 EXPORT_SYMBOL_GPL(bpf_prog_get_type);
 
 /* last field in 'union bpf_attr' used by this command */
-#define        BPF_PROG_LOAD_LAST_FIELD prog_flags
+#define        BPF_PROG_LOAD_LAST_FIELD prog_name
 
 static int bpf_prog_load(union bpf_attr *attr)
 {
@@ -1037,6 +1064,11 @@ static int bpf_prog_load(union bpf_attr *attr)
        if (err < 0)
                goto free_prog;
 
+       prog->aux->load_time = ktime_get_boot_ns();
+       err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name);
+       if (err)
+               goto free_prog;
+
        /* run eBPF verifier */
        err = bpf_check(&prog, attr);
        if (err < 0)
@@ -1358,8 +1390,25 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
 
        info.type = prog->type;
        info.id = prog->aux->id;
+       info.load_time = prog->aux->load_time;
+       info.created_by_uid = from_kuid_munged(current_user_ns(),
+                                              prog->aux->user->uid);
 
        memcpy(info.tag, prog->tag, sizeof(prog->tag));
+       memcpy(info.name, prog->aux->name, sizeof(prog->aux->name));
+
+       ulen = info.nr_map_ids;
+       info.nr_map_ids = prog->aux->used_map_cnt;
+       ulen = min_t(u32, info.nr_map_ids, ulen);
+       if (ulen) {
+               u32 *user_map_ids = (u32 *)info.map_ids;
+               u32 i;
+
+               for (i = 0; i < ulen; i++)
+                       if (put_user(prog->aux->used_maps[i]->id,
+                                    &user_map_ids[i]))
+                               return -EFAULT;
+       }
 
        if (!capable(CAP_SYS_ADMIN)) {
                info.jited_prog_len = 0;