From b075241890641122df79c130149601c942a310a5 Mon Sep 17 00:00:00 2001 From: Alexey Makhalov <amakhalov@vmware.com> Date: Wed, 19 Jul 2017 19:53:14 +0000 Subject: [PATCH 1/2] 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 | 15 ++++----------- scripts/gen-tunables.awk | 12 ++++++++++-- 2 files changed, 14 insertions(+), 13 deletions(-) diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c index 44c160c..8e02a95 100644 --- a/elf/dl-tunables.c +++ b/elf/dl-tunables.c @@ -86,18 +86,11 @@ 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; \ @@ -117,17 +110,17 @@ 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 ccdd0c6..6221990 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" -- 2.9.3