2 files changed, 38 insertions, 33 deletions

diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index f655b926e432..8f70dc181e23 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -173,6 +173,11 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
 
 #define BPF_MAX_SUBPROGS 256
 
+struct bpf_subprog_info {
+        u32 start; /* insn idx of function entry point */
+        u16 stack_depth; /* max. stack depth used by this function */
+};
+
 /* single container for all structs
  * one verifier_env per bpf_check() call
  */
@@ -191,9 +196,7 @@ struct bpf_verifier_env {
         bool seen_direct_write;
         struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
         struct bpf_verifier_log log;
-        u32 subprog_starts[BPF_MAX_SUBPROGS + 1];
-        /* computes the stack depth of each bpf function */
-        u16 subprog_stack_depth[BPF_MAX_SUBPROGS + 1];
+        struct bpf_subprog_info subprog_info[BPF_MAX_SUBPROGS + 1];
         u32 subprog_cnt;
 };
 
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8e8e582a7c03..5b293b4abb70 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -741,18 +741,19 @@ enum reg_arg_type {
 
 static int cmp_subprogs(const void *a, const void *b)
 {
-        return *(int *)a - *(int *)b;
+        return ((struct bpf_subprog_info *)a)->start -
+               ((struct bpf_subprog_info *)b)->start;
 }
 
 static int find_subprog(struct bpf_verifier_env *env, int off)
 {
-        u32 *p;
+        struct bpf_subprog_info *p;
 
-        p = bsearch(&off, env->subprog_starts, env->subprog_cnt,
-                    sizeof(env->subprog_starts[0]), cmp_subprogs);
+        p = bsearch(&off, env->subprog_info, env->subprog_cnt,
+                    sizeof(env->subprog_info[0]), cmp_subprogs);
         if (!p)
                 return -ENOENT;
-        return p - env->subprog_starts;
+        return p - env->subprog_info;
 
 }
 
@@ -772,15 +773,16 @@ static int add_subprog(struct bpf_verifier_env *env, int off)
                 verbose(env, "too many subprograms\n");
                 return -E2BIG;
         }
-        env->subprog_starts[env->subprog_cnt++] = off;
-        sort(env->subprog_starts, env->subprog_cnt,
-             sizeof(env->subprog_starts[0]), cmp_subprogs, NULL);
+        env->subprog_info[env->subprog_cnt++].start = off;
+        sort(env->subprog_info, env->subprog_cnt,
+             sizeof(env->subprog_info[0]), cmp_subprogs, NULL);
         return 0;
 }
 
 static int check_subprogs(struct bpf_verifier_env *env)
 {
         int i, ret, subprog_start, subprog_end, off, cur_subprog = 0;
+        struct bpf_subprog_info *subprog = env->subprog_info;
         struct bpf_insn *insn = env->prog->insnsi;
         int insn_cnt = env->prog->len;
 
@@ -810,14 +812,14 @@ static int check_subprogs(struct bpf_verifier_env *env)
 
         if (env->log.level > 1)
                 for (i = 0; i < env->subprog_cnt; i++)
-                        verbose(env, "func#%d @%d\n", i, env->subprog_starts[i]);
+                        verbose(env, "func#%d @%d\n", i, subprog[i].start);
 
         /* now check that all jumps are within the same subprog */
         subprog_start = 0;
         if (env->subprog_cnt == cur_subprog + 1)
                 subprog_end = insn_cnt;
         else
-                subprog_end = env->subprog_starts[cur_subprog + 1];
+                subprog_end = subprog[cur_subprog + 1].start;
         for (i = 0; i < insn_cnt; i++) {
                 u8 code = insn[i].code;
 
@@ -846,8 +848,7 @@ next:
                         if (env->subprog_cnt == cur_subprog + 1)
                                 subprog_end = insn_cnt;
                         else
-                                subprog_end =
-                                        env->subprog_starts[cur_subprog + 1];
+                                subprog_end = subprog[cur_subprog + 1].start;
                 }
         }
         return 0;
@@ -1480,13 +1481,13 @@ static int update_stack_depth(struct bpf_verifier_env *env,
                               const struct bpf_func_state *func,
                               int off)
 {
-        u16 stack = env->subprog_stack_depth[func->subprogno];
+        u16 stack = env->subprog_info[func->subprogno].stack_depth;
 
         if (stack >= -off)
                 return 0;
 
         /* update known max for given subprogram */
-        env->subprog_stack_depth[func->subprogno] = -off;
+        env->subprog_info[func->subprogno].stack_depth = -off;
         return 0;
 }
 
@@ -1498,7 +1499,8 @@ static int update_stack_depth(struct bpf_verifier_env *env,
  */
 static int check_max_stack_depth(struct bpf_verifier_env *env)
 {
-        int depth = 0, frame = 0, subprog = 0, i = 0, subprog_end;
+        int depth = 0, frame = 0, idx = 0, i = 0, subprog_end;
+        struct bpf_subprog_info *subprog = env->subprog_info;
         struct bpf_insn *insn = env->prog->insnsi;
         int insn_cnt = env->prog->len;
         int ret_insn[MAX_CALL_FRAMES];
@@ -1508,17 +1510,17 @@ process_func:
         /* round up to 32-bytes, since this is granularity
          * of interpreter stack size
          */
-        depth += round_up(max_t(u32, env->subprog_stack_depth[subprog], 1), 32);
+        depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
         if (depth > MAX_BPF_STACK) {
                 verbose(env, "combined stack size of %d calls is %d. Too large\n",
                         frame + 1, depth);
                 return -EACCES;
         }
 continue_func:
-        if (env->subprog_cnt == subprog + 1)
+        if (env->subprog_cnt == idx + 1)
                 subprog_end = insn_cnt;
         else
-                subprog_end = env->subprog_starts[subprog + 1];
+                subprog_end = subprog[idx + 1].start;
         for (; i < subprog_end; i++) {
                 if (insn[i].code != (BPF_JMP | BPF_CALL))
                         continue;
@@ -1526,12 +1528,12 @@ continue_func:
                         continue;
                 /* remember insn and function to return to */
                 ret_insn[frame] = i + 1;
-                ret_prog[frame] = subprog;
+                ret_prog[frame] = idx;
 
                 /* find the callee */
                 i = i + insn[i].imm + 1;
-                subprog = find_subprog(env, i);
-                if (subprog < 0) {
+                idx = find_subprog(env, i);
+                if (idx < 0) {
                         WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
                                   i);
                         return -EFAULT;
@@ -1548,10 +1550,10 @@ continue_func:
          */
         if (frame == 0)
                 return 0;
-        depth -= round_up(max_t(u32, env->subprog_stack_depth[subprog], 1), 32);
+        depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
         frame--;
         i = ret_insn[frame];
-        subprog = ret_prog[frame];
+        idx = ret_prog[frame];
         goto continue_func;
 }
 
@@ -1567,7 +1569,7 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env,
                           start);
                 return -EFAULT;
         }
-        return env->subprog_stack_depth[subprog];
+        return env->subprog_info[subprog].stack_depth;
 }
 #endif
 
@@ -4926,14 +4928,14 @@ process_bpf_exit:
         verbose(env, "processed %d insns (limit %d), stack depth ",
                 insn_processed, BPF_COMPLEXITY_LIMIT_INSNS);
         for (i = 0; i < env->subprog_cnt; i++) {
-                u32 depth = env->subprog_stack_depth[i];
+                u32 depth = env->subprog_info[i].stack_depth;
 
                 verbose(env, "%d", depth);
                 if (i + 1 < env->subprog_cnt)
                         verbose(env, "+");
         }
         verbose(env, "\n");
-        env->prog->aux->stack_depth = env->subprog_stack_depth[0];
+        env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
         return 0;
 }
 
@@ -5140,9 +5142,9 @@ static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len
         if (len == 1)
                 return;
         for (i = 0; i < env->subprog_cnt; i++) {
-                if (env->subprog_starts[i] < off)
+                if (env->subprog_info[i].start < off)
                         continue;
-                env->subprog_starts[i] += len - 1;
+                env->subprog_info[i].start += len - 1;
         }
 }
 
@@ -5340,7 +5342,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
                 if (env->subprog_cnt == i + 1)
                         subprog_end = prog->len;
                 else
-                        subprog_end = env->subprog_starts[i + 1];
+                        subprog_end = env->subprog_info[i + 1].start;
 
                 len = subprog_end - subprog_start;
                 func[i] = bpf_prog_alloc(bpf_prog_size(len), GFP_USER);
@@ -5357,7 +5359,7 @@ static int jit_subprogs(struct bpf_verifier_env *env)
                  * Long term would need debug info to populate names
                  */
                 func[i]->aux->name[0] = 'F';
-                func[i]->aux->stack_depth = env->subprog_stack_depth[i];
+                func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
                 func[i]->jit_requested = 1;
                 func[i] = bpf_int_jit_compile(func[i]);
                 if (!func[i]->jited) {