bpf: show main program address and length in bpf_prog_info

Currently, when there is no subprog (prog->aux->func_cnt == 0),
bpf_prog_info does not return any jited_ksyms or jited_func_lens. This
patch adds main program address (prog->bpf_func) and main program
length (prog->jited_len) to bpf_prog_info.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 24 insertions, 9 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 34a9eef5992c..9418174c276c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2158,11 +2158,11 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
         }
 
         ulen = info.nr_jited_ksyms;
-        info.nr_jited_ksyms = prog->aux->func_cnt;
+        info.nr_jited_ksyms = prog->aux->func_cnt ? : 1;
         if (info.nr_jited_ksyms && ulen) {
                 if (bpf_dump_raw_ok()) {
+                        unsigned long ksym_addr;
                         u64 __user *user_ksyms;
-                        ulong ksym_addr;
                         u32 i;
 
                         /* copy the address of the kernel symbol
@@ -2170,9 +2170,17 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
                          */
                         ulen = min_t(u32, info.nr_jited_ksyms, ulen);
                         user_ksyms = u64_to_user_ptr(info.jited_ksyms);
-                        for (i = 0; i < ulen; i++) {
-                                ksym_addr = (ulong) prog->aux->func[i]->bpf_func;
-                                if (put_user((u64) ksym_addr, &user_ksyms[i]))
+                        if (prog->aux->func_cnt) {
+                                for (i = 0; i < ulen; i++) {
+                                        ksym_addr = (unsigned long)
+                                                prog->aux->func[i]->bpf_func;
+                                        if (put_user((u64) ksym_addr,
+                                                     &user_ksyms[i]))
+                                                return -EFAULT;
+                                }
+                        } else {
+                                ksym_addr = (unsigned long) prog->bpf_func;
+                                if (put_user((u64) ksym_addr, &user_ksyms[0]))
                                         return -EFAULT;
                         }
                 } else {
@@ -2181,7 +2189,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
         }
 
         ulen = info.nr_jited_func_lens;
-        info.nr_jited_func_lens = prog->aux->func_cnt;
+        info.nr_jited_func_lens = prog->aux->func_cnt ? : 1;
         if (info.nr_jited_func_lens && ulen) {
                 if (bpf_dump_raw_ok()) {
                         u32 __user *user_lens;
@@ -2190,9 +2198,16 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
                         /* copy the JITed image lengths for each function */
                         ulen = min_t(u32, info.nr_jited_func_lens, ulen);
                         user_lens = u64_to_user_ptr(info.jited_func_lens);
-                        for (i = 0; i < ulen; i++) {
-                                func_len = prog->aux->func[i]->jited_len;
-                                if (put_user(func_len, &user_lens[i]))
+                        if (prog->aux->func_cnt) {
+                                for (i = 0; i < ulen; i++) {
+                                        func_len =
+                                                prog->aux->func[i]->jited_len;
+                                        if (put_user(func_len, &user_lens[i]))
+                                                return -EFAULT;
+                                }
+                        } else {
+                                func_len = prog->jited_len;
+                                if (put_user(func_len, &user_lens[0]))
                                         return -EFAULT;
                         }
                 } else {