From cebcb9f864d4ca29e155363e71b7de6826d13cf1 Mon Sep 17 00:00:00 2001
From: Alexey Makhalov <amakhalov@vmware.com>
Date: Wed, 27 Sep 2017 02:44:09 +0530
Subject: [PATCH] Fix range check in do_tunable_update_val

Current implementation of tunables does not set arena_max and arena_test
values. Any value provided by glibc.malloc.arena_max and
glibc.malloc.arena_test parameters is ignored.

These tunables have minval value set to 1 (see elf/dl-tunables.list file)
and undefined maxval value. In that case default value (which is 0. see
scripts/gen-tunables.awk) is being used to set maxval.

For instance, generated tunable_list[] entry for arena_max is:
(gdb) p *cur
$1 = {name = 0x7ffff7df6217 "glibc.malloc.arena_max",
 type = {type_code = TUNABLE_TYPE_SIZE_T, min = 1, max = 0},
  val = {numval = 0, strval = 0x0}, initialized = false,
   security_level = TUNABLE_SECLEVEL_SXID_IGNORE,
    env_alias = 0x7ffff7df622e "MALLOC_ARENA_MAX"}

As a result, any value of glibc.malloc.arena_max is ignored by
TUNABLE_SET_VAL_IF_VALID_RANGE macro
  __type min = (__cur)->type.min;                    <- initialized to 1
  __type max = (__cur)->type.max;                    <- initialized to 0!
  if (min == max)                                    <- false
    {
      min = __default_min;
      max = __default_max;
    }
  if ((__type) (__val) >= min && (__type) (val) <= max)  <- false
    {
      (__cur)->val.numval = val;
      (__cur)->initialized = true;
    }

Assigning correct min/max values at a build time fixes a problem.
Plus, a bit of optimization: Setting of default min/max values for the
given type at a run time might be eliminated.

	* elf/dl-tunables.c (do_tunable_update_val): Range checking fix.
	* scripts/gen-tunables.awk: Set unspecified minval and/or maxval
	values to correct default value for given type.
---
 ChangeLog                |  6 ++++++
 elf/dl-tunables.c        | 15 ++++-----------
 scripts/gen-tunables.awk | 12 ++++++++++--
 3 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d15964db69..0426d63690 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-26  Alexey Makhalov  <amakhalov@vmware.com>
+
+	* elf/dl-tunables.c (do_tunable_update_val): Range checking fix.
+	* scripts/gen-tunables.awk: Set unspecified minval and/or maxval
+	values to correct default value for given type.
+
 2017-09-26  H.J. Lu  <hongjiu.lu@intel.com>
 
 	[BZ #22101]
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index b964a09413..cc2c637543 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -89,18 +89,11 @@ get_next_env (char **envp, char **name, size_t *namelen, char **val,
   return NULL;
 }
 
-#define TUNABLE_SET_VAL_IF_VALID_RANGE(__cur, __val, __type, __default_min, \
-				       __default_max)			      \
+#define TUNABLE_SET_VAL_IF_VALID_RANGE(__cur, __val, __type)		      \
 ({									      \
   __type min = (__cur)->type.min;					      \
   __type max = (__cur)->type.max;					      \
 									      \
-  if (min == max)							      \
-    {									      \
-      min = __default_min;						      \
-      max = __default_max;						      \
-    }									      \
-									      \
   if ((__type) (__val) >= min && (__type) (val) <= max)			      \
     {									      \
       (__cur)->val.numval = val;					      \
@@ -120,17 +113,17 @@ do_tunable_update_val (tunable_t *cur, const void *valp)
     {
     case TUNABLE_TYPE_INT_32:
 	{
-	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, int64_t, INT32_MIN, INT32_MAX);
+	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, int64_t);
 	  break;
 	}
     case TUNABLE_TYPE_UINT_64:
 	{
-	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t, 0, UINT64_MAX);
+	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t);
 	  break;
 	}
     case TUNABLE_TYPE_SIZE_T:
 	{
-	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t, 0, SIZE_MAX);
+	  TUNABLE_SET_VAL_IF_VALID_RANGE (cur, val, uint64_t);
 	  break;
 	}
     case TUNABLE_TYPE_STRING:
diff --git a/scripts/gen-tunables.awk b/scripts/gen-tunables.awk
index ccdd0c6c71..622199061a 100644
--- a/scripts/gen-tunables.awk
+++ b/scripts/gen-tunables.awk
@@ -1,6 +1,14 @@
 # Generate dl-tunable-list.h from dl-tunables.list
 
 BEGIN {
+  min_of["STRING"]="0"
+  max_of["STRING"]="0"
+  min_of["INT_32"]="INT32_MIN"
+  max_of["INT_32"]="INT32_MAX"
+  min_of["UINT_64"]="0"
+  max_of["UINT_64"]="UINT64_MAX"
+  min_of["SIZE_T"]="0"
+  max_of["SIZE_T"]="SIZE_MAX"
   tunable=""
   ns=""
   top_ns=""
@@ -43,10 +51,10 @@ $1 == "}" {
       types[top_ns,ns,tunable] = "STRING"
     }
     if (!minvals[top_ns,ns,tunable]) {
-      minvals[top_ns,ns,tunable] = "0"
+      minvals[top_ns,ns,tunable] = min_of[types[top_ns,ns,tunable]]
     }
     if (!maxvals[top_ns,ns,tunable]) {
-      maxvals[top_ns,ns,tunable] = "0"
+      maxvals[top_ns,ns,tunable] = max_of[types[top_ns,ns,tunable]]
     }
     if (!env_alias[top_ns,ns,tunable]) {
       env_alias[top_ns,ns,tunable] = "NULL"