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tunables signed/unsigned bug & patch
- From: DJ Delorie <dj at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Thu, 19 Jan 2017 13:22:38 -0500
- Subject: tunables signed/unsigned bug & patch
- Authentication-results: sourceware.org; auth=none
The range check for size_t tunables was checking against
(signed)(0xfff...fff), which is -1, so never passed (val>0 && val<-1).
This means half the existing tunables would never work :-(
I couldn't think of a clean way to handle both signed and unsigned in
the same function, so I split it into separate functions.
As an aside, tunables_strtoul() parses signed values but returns
unsigned values. Ideally that would be split out too, but that's a
lot more code duplication.
DJ
diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
index e0119d1..c2f487a 100644
--- a/elf/dl-tunables.c
+++ b/elf/dl-tunables.c
@@ -172,10 +172,10 @@ tunables_strtoul (const char *nptr)
explicit constraints of the tunable or with the implicit constraints of its
type. */
static void
-tunable_set_val_if_valid_range (tunable_t *cur, const char *strval,
+tunable_set_val_if_valid_range_signed (tunable_t *cur, const char *strval,
int64_t default_min, int64_t default_max)
{
- int64_t val = tunables_strtoul (strval);
+ int64_t val = (int64_t) tunables_strtoul (strval);
int64_t min = cur->type.min;
int64_t max = cur->type.max;
@@ -193,6 +193,28 @@ tunable_set_val_if_valid_range (tunable_t *cur, const char *strval,
}
}
+static void
+tunable_set_val_if_valid_range_unsigned (tunable_t *cur, const char *strval,
+ uint64_t default_min, uint64_t default_max)
+{
+ uint64_t val = (uint64_t) tunables_strtoul (strval);
+
+ uint64_t min = cur->type.min;
+ uint64_t max = cur->type.max;
+
+ if (min == max)
+ {
+ min = default_min;
+ max = default_max;
+ }
+
+ if (val >= min && val <= max)
+ {
+ cur->val.numval = val;
+ cur->strval = strval;
+ }
+}
+
/* Validate range of the input value and initialize the tunable CUR if it looks
good. */
static void
@@ -202,12 +224,12 @@ tunable_initialize (tunable_t *cur, const char *strval)
{
case TUNABLE_TYPE_INT_32:
{
- tunable_set_val_if_valid_range (cur, strval, INT32_MIN, INT32_MAX);
+ tunable_set_val_if_valid_range_signed (cur, strval, INT32_MIN, INT32_MAX);
break;
}
case TUNABLE_TYPE_SIZE_T:
{
- tunable_set_val_if_valid_range (cur, strval, 0, SIZE_MAX);
+ tunable_set_val_if_valid_range_unsigned (cur, strval, 0, SIZE_MAX);
break;
}
case TUNABLE_TYPE_STRING: