[v6,2/2] elf: Do not set invalid tunables values
Checks
Context |
Check |
Description |
redhat-pt-bot/TryBot-apply_patch |
success
|
Patch applied to master at the time it was sent
|
redhat-pt-bot/TryBot-32bit |
success
|
Build for i686
|
linaro-tcwg-bot/tcwg_glibc_build--master-arm |
success
|
Testing passed
|
linaro-tcwg-bot/tcwg_glibc_build--master-aarch64 |
success
|
Testing passed
|
linaro-tcwg-bot/tcwg_glibc_check--master-arm |
success
|
Testing passed
|
linaro-tcwg-bot/tcwg_glibc_check--master-aarch64 |
success
|
Testing passed
|
Commit Message
The loader now warns for invalid and out-of-range tunable values. The
patch also fixes the parsing of size_t maximum values, where
_dl_strtoul was failing for large values close to SIZE_MAX.
Checked on x86_64-linux-gnu.
---
elf/dl-misc.c | 10 +++++++++-
elf/dl-tunables.c | 35 ++++++++++++++++++++++++++++++-----
elf/tst-tunables.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 69 insertions(+), 6 deletions(-)
Comments
On 2023-12-06 08:24, Adhemerval Zanella wrote:
> The loader now warns for invalid and out-of-range tunable values. The
> patch also fixes the parsing of size_t maximum values, where
> _dl_strtoul was failing for large values close to SIZE_MAX.
>
> Checked on x86_64-linux-gnu.
> ---
Tiny nit below, OK otherwise. Please fix that, post a [committed] patch
to the list and push it.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> elf/dl-misc.c | 10 +++++++++-
> elf/dl-tunables.c | 35 ++++++++++++++++++++++++++++++-----
> elf/tst-tunables.c | 30 ++++++++++++++++++++++++++++++
> 3 files changed, 69 insertions(+), 6 deletions(-)
>
> diff --git a/elf/dl-misc.c b/elf/dl-misc.c
> index 5b84adc2f4..8dccb3a9a9 100644
> --- a/elf/dl-misc.c
> +++ b/elf/dl-misc.c
> @@ -174,6 +174,9 @@ _dl_strtoul (const char *nptr, char **endptr)
> return 0UL;
> }
>
> + uint64_t cutoff = (UINT64_MAX * 2UL + 1UL) / 10;
> + uint64_t cutlim = (UINT64_MAX * 2UL + 1UL) % 10;
> +
> int base = 10;
> max_digit = 9;
> if (*nptr == '0')
> @@ -182,14 +185,19 @@ _dl_strtoul (const char *nptr, char **endptr)
> {
> base = 16;
> nptr += 2;
> + cutoff = (UINT64_MAX * 2UL + 1UL) / 16;
> + cutlim = (UINT64_MAX * 2UL + 1UL) % 16;
> }
> else
> {
> base = 8;
> max_digit = 7;
> + cutoff = (UINT64_MAX * 2UL + 1UL) / 8;
> + cutlim = (UINT64_MAX * 2UL + 1UL) % 8;
> }
> }
>
> +
Spurious newline.
> while (1)
> {
> int digval;
> @@ -207,7 +215,7 @@ _dl_strtoul (const char *nptr, char **endptr)
> else
> break;
>
> - if (result >= (UINT64_MAX - digval) / base)
> + if (result > cutoff || (result == cutoff && digval > cutlim))
> {
> if (endptr != NULL)
> *endptr = (char *) nptr;
> diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
> index 3d41e8e28e..092b696484 100644
> --- a/elf/dl-tunables.c
> +++ b/elf/dl-tunables.c
> @@ -69,16 +69,27 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp,
> {
> tunable_num_t val, min, max;
>
> - if (cur->type.type_code == TUNABLE_TYPE_STRING)
> + switch (cur->type.type_code)
> {
> + case TUNABLE_TYPE_STRING:
> cur->val.strval = valp->strval;
> cur->initialized = true;
> return;
> + case TUNABLE_TYPE_INT_32:
> + val = (int32_t) valp->numval;
> + break;
> + case TUNABLE_TYPE_UINT_64:
> + val = (int64_t) valp->numval;
> + break;
> + case TUNABLE_TYPE_SIZE_T:
> + val = (size_t) valp->numval;
> + break;
> + default:
> + __builtin_unreachable ();
> }
>
> 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;
>
> @@ -109,16 +120,24 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp,
>
> /* Validate range of the input value and initialize the tunable CUR if it looks
> good. */
> -static void
> +static bool
> tunable_initialize (tunable_t *cur, const char *strval, size_t len)
> {
> tunable_val_t val = { 0 };
>
> if (cur->type.type_code != TUNABLE_TYPE_STRING)
> - val.numval = (tunable_num_t) _dl_strtoul (strval, NULL);
> + {
> + char *endptr = NULL;
> + uint64_t numval = _dl_strtoul (strval, &endptr);
> + if (endptr != strval + len)
> + return false;
> + val.numval = (tunable_num_t) numval;
> + }
> else
> val.strval = (struct tunable_str_t) { strval, len };
> do_tunable_update_val (cur, &val, NULL, NULL);
> +
> + return true;
> }
>
> bool
> @@ -225,7 +244,13 @@ parse_tunables (const char *valstring)
> }
>
> for (int i = 0; i < ntunables; i++)
> - tunable_initialize (tunables[i].t, tunables[i].value, tunables[i].len);
> + if (!tunable_initialize (tunables[i].t, tunables[i].value,
> + tunables[i].len))
> + _dl_error_printf ("WARNING: ld.so: invalid GLIBC_TUNABLES value `%.*s' "
> + "for option `%s': ignored.\n",
> + (int) tunables[i].len,
> + tunables[i].value,
> + tunables[i].t->name);
> }
>
> /* Initialize the tunables list from the environment. For now we only use the
> diff --git a/elf/tst-tunables.c b/elf/tst-tunables.c
> index 188345b070..d6a1e1b3ac 100644
> --- a/elf/tst-tunables.c
> +++ b/elf/tst-tunables.c
> @@ -53,6 +53,13 @@ static const struct test_t
> 4096,
> 0,
> },
> + {
> + "GLIBC_TUNABLES",
> + "glibc.malloc.mmap_threshold=-1",
> + 0,
> + SIZE_MAX,
> + 0,
> + },
> /* Empty tunable are ignored. */
> {
> "GLIBC_TUNABLES",
> @@ -224,6 +231,29 @@ static const struct test_t
> 0,
> 0,
> },
> + /* Invalid numbers are ignored. */
> + {
> + "GLIBC_TUNABLES",
> + "glibc.malloc.check=abc:glibc.malloc.mmap_threshold=4096",
> + 0,
> + 4096,
> + 0,
> + },
> + {
> + "GLIBC_TUNABLES",
> + "glibc.malloc.check=2:glibc.malloc.mmap_threshold=abc",
> + 2,
> + 0,
> + 0,
> + },
> + {
> + "GLIBC_TUNABLES",
> + /* SIZE_MAX + 1 */
> + "glibc.malloc.mmap_threshold=18446744073709551616",
> + 0,
> + 0,
> + 0,
> + },
> /* Also check some tunable aliases. */
> {
> "MALLOC_CHECK_",
@@ -174,6 +174,9 @@ _dl_strtoul (const char *nptr, char **endptr)
return 0UL;
}
+ uint64_t cutoff = (UINT64_MAX * 2UL + 1UL) / 10;
+ uint64_t cutlim = (UINT64_MAX * 2UL + 1UL) % 10;
+
int base = 10;
max_digit = 9;
if (*nptr == '0')
@@ -182,14 +185,19 @@ _dl_strtoul (const char *nptr, char **endptr)
{
base = 16;
nptr += 2;
+ cutoff = (UINT64_MAX * 2UL + 1UL) / 16;
+ cutlim = (UINT64_MAX * 2UL + 1UL) % 16;
}
else
{
base = 8;
max_digit = 7;
+ cutoff = (UINT64_MAX * 2UL + 1UL) / 8;
+ cutlim = (UINT64_MAX * 2UL + 1UL) % 8;
}
}
+
while (1)
{
int digval;
@@ -207,7 +215,7 @@ _dl_strtoul (const char *nptr, char **endptr)
else
break;
- if (result >= (UINT64_MAX - digval) / base)
+ if (result > cutoff || (result == cutoff && digval > cutlim))
{
if (endptr != NULL)
*endptr = (char *) nptr;
@@ -69,16 +69,27 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp,
{
tunable_num_t val, min, max;
- if (cur->type.type_code == TUNABLE_TYPE_STRING)
+ switch (cur->type.type_code)
{
+ case TUNABLE_TYPE_STRING:
cur->val.strval = valp->strval;
cur->initialized = true;
return;
+ case TUNABLE_TYPE_INT_32:
+ val = (int32_t) valp->numval;
+ break;
+ case TUNABLE_TYPE_UINT_64:
+ val = (int64_t) valp->numval;
+ break;
+ case TUNABLE_TYPE_SIZE_T:
+ val = (size_t) valp->numval;
+ break;
+ default:
+ __builtin_unreachable ();
}
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;
@@ -109,16 +120,24 @@ do_tunable_update_val (tunable_t *cur, const tunable_val_t *valp,
/* Validate range of the input value and initialize the tunable CUR if it looks
good. */
-static void
+static bool
tunable_initialize (tunable_t *cur, const char *strval, size_t len)
{
tunable_val_t val = { 0 };
if (cur->type.type_code != TUNABLE_TYPE_STRING)
- val.numval = (tunable_num_t) _dl_strtoul (strval, NULL);
+ {
+ char *endptr = NULL;
+ uint64_t numval = _dl_strtoul (strval, &endptr);
+ if (endptr != strval + len)
+ return false;
+ val.numval = (tunable_num_t) numval;
+ }
else
val.strval = (struct tunable_str_t) { strval, len };
do_tunable_update_val (cur, &val, NULL, NULL);
+
+ return true;
}
bool
@@ -225,7 +244,13 @@ parse_tunables (const char *valstring)
}
for (int i = 0; i < ntunables; i++)
- tunable_initialize (tunables[i].t, tunables[i].value, tunables[i].len);
+ if (!tunable_initialize (tunables[i].t, tunables[i].value,
+ tunables[i].len))
+ _dl_error_printf ("WARNING: ld.so: invalid GLIBC_TUNABLES value `%.*s' "
+ "for option `%s': ignored.\n",
+ (int) tunables[i].len,
+ tunables[i].value,
+ tunables[i].t->name);
}
/* Initialize the tunables list from the environment. For now we only use the
@@ -53,6 +53,13 @@ static const struct test_t
4096,
0,
},
+ {
+ "GLIBC_TUNABLES",
+ "glibc.malloc.mmap_threshold=-1",
+ 0,
+ SIZE_MAX,
+ 0,
+ },
/* Empty tunable are ignored. */
{
"GLIBC_TUNABLES",
@@ -224,6 +231,29 @@ static const struct test_t
0,
0,
},
+ /* Invalid numbers are ignored. */
+ {
+ "GLIBC_TUNABLES",
+ "glibc.malloc.check=abc:glibc.malloc.mmap_threshold=4096",
+ 0,
+ 4096,
+ 0,
+ },
+ {
+ "GLIBC_TUNABLES",
+ "glibc.malloc.check=2:glibc.malloc.mmap_threshold=abc",
+ 2,
+ 0,
+ 0,
+ },
+ {
+ "GLIBC_TUNABLES",
+ /* SIZE_MAX + 1 */
+ "glibc.malloc.mmap_threshold=18446744073709551616",
+ 0,
+ 0,
+ 0,
+ },
/* Also check some tunable aliases. */
{
"MALLOC_CHECK_",