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authorSiddhesh Poyarekar <siddhesh@sourceware.org>2021-03-16 18:31:02 +0530
committerSiddhesh Poyarekar <siddhesh@sourceware.org>2021-04-07 14:06:18 +0530
commitd1a3dcabf2f89233a99a4a9be08f9f407da0b6b4 (patch)
tree923c89bfe24a3ab053337bcf3eb36675ee276c68 /elf
parentbf6b6243c9fe6e9727282ed63f774698e730cedd (diff)
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tunables: Fix comparison of tunable values
The simplification of tunable_set interfaces took care of signed/unsigned conversions while setting values, but comparison with bounds ended up being incorrect; comparing TUNABLE_SIZE_T values for example will fail because SIZE_MAX is seen as -1. Add comparison helpers that take tunable types into account and use them to do comparison instead.
Diffstat (limited to 'elf')
-rw-r--r--elf/dl-tunable-types.h17
-rw-r--r--elf/dl-tunables.c25
-rw-r--r--elf/dl-tunables.h18
3 files changed, 49 insertions, 11 deletions
diff --git a/elf/dl-tunable-types.h b/elf/dl-tunable-types.h
index 626ca334be..39bf738d93 100644
--- a/elf/dl-tunable-types.h
+++ b/elf/dl-tunable-types.h
@@ -81,4 +81,21 @@ struct _tunable
typedef struct _tunable tunable_t;
+static __always_inline bool
+unsigned_tunable_type (tunable_type_code_t t)
+{
+ switch (t)
+ {
+ case TUNABLE_TYPE_INT_32:
+ return false;
+ case TUNABLE_TYPE_UINT_64:
+ case TUNABLE_TYPE_SIZE_T:
+ return true;
+ case TUNABLE_TYPE_STRING:
+ default:
+ break;
+ }
+ __builtin_unreachable ();
+}
+
#endif
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index a2be9cde2f..8b751dcf0d 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -107,32 +107,35 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp,
return;
}
+ bool unsigned_cmp = unsigned_tunable_type (cur->type.type_code);
+
val = valp->numval;
min = minp != NULL ? *minp : cur->type.min;
max = maxp != NULL ? *maxp : cur->type.max;
/* We allow only increasingly restrictive bounds. */
- if (min < cur->type.min)
+ if (tunable_val_lt (min, cur->type.min, unsigned_cmp))
min = cur->type.min;
- if (max > cur->type.max)
+ if (tunable_val_gt (max, cur->type.max, unsigned_cmp))
max = cur->type.max;
/* Skip both bounds if they're inconsistent. */
- if (min > max)
+ if (tunable_val_gt (min, max, unsigned_cmp))
{
min = cur->type.min;
max = cur->type.max;
}
- /* Write everything out if the value and the bounds are valid. */
- if (min <= val && val <= max)
- {
- cur->val.numval = val;
- cur->type.min = min;
- cur->type.max = max;
- cur->initialized = true;
- }
+ /* Bail out if the bounds are not valid. */
+ if (tunable_val_lt (val, min, unsigned_cmp)
+ || tunable_val_lt (max, val, unsigned_cmp))
+ return;
+
+ cur->val.numval = val;
+ cur->type.min = min;
+ cur->type.max = max;
+ cur->initialized = true;
}
/* Validate range of the input value and initialize the tunable CUR if it looks
diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h
index ba7ae6b52e..3880e4aab6 100644
--- a/elf/dl-tunables.h
+++ b/elf/dl-tunables.h
@@ -115,6 +115,24 @@ rtld_hidden_proto (__tunable_set_val)
/* The default value for TUNABLES_FRONTEND. */
# define TUNABLES_FRONTEND_yes TUNABLES_FRONTEND_valstring
+static __always_inline bool
+tunable_val_lt (tunable_num_t lhs, tunable_num_t rhs, bool unsigned_cmp)
+{
+ if (unsigned_cmp)
+ return (uintmax_t) lhs < (uintmax_t) rhs;
+ else
+ return lhs < rhs;
+}
+
+static __always_inline bool
+tunable_val_gt (tunable_num_t lhs, tunable_num_t rhs, bool unsigned_cmp)
+{
+ if (unsigned_cmp)
+ return (uintmax_t) lhs > (uintmax_t) rhs;
+ else
+ return lhs > rhs;
+}
+
/* Compare two name strings, bounded by the name hardcoded in glibc. */
static __always_inline bool
tunable_is_name (const char *orig, const char *envname)