[v3,06/19] elf: Do not parse ill-formatted strings
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Commit Message
Instead of ignoring ill-formatted tunable strings, first, check all the
tunable definitions are correct and then set each tunable value. It
means that partially invalid strings, like "key1=value1:key2=key2=value'
or 'key1=value':key2=value2=value2' do not enable 'key1=value1'. It
avoids possible user-defined errors in tunable definitions.
Checked on x86_64-linux-gnu.
---
elf/dl-tunables.c | 48 ++++++++++++++++++++++++++++++++++------------
elf/tst-tunables.c | 13 +++++++++----
2 files changed, 45 insertions(+), 16 deletions(-)
Comments
On 2023-11-06 15:25, Adhemerval Zanella wrote:
> Instead of ignoring ill-formatted tunable strings, first, check all the
> tunable definitions are correct and then set each tunable value. It
> means that partially invalid strings, like "key1=value1:key2=key2=value'
> or 'key1=value':key2=value2=value2' do not enable 'key1=value1'. It
> avoids possible user-defined errors in tunable definitions.
>
> Checked on x86_64-linux-gnu.
> ---
Only tiny language nits below, LGTM otherwise.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> elf/dl-tunables.c | 48 ++++++++++++++++++++++++++++++++++------------
> elf/tst-tunables.c | 13 +++++++++----
> 2 files changed, 45 insertions(+), 16 deletions(-)
>
> diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c
> index 082a76d9c4..e1198869d6 100644
> --- a/elf/dl-tunables.c
> +++ b/elf/dl-tunables.c
> @@ -154,17 +154,29 @@ __tunable_set_val (tunable_id_t id, tunable_val_t *valp, tunable_num_t *minp,
> do_tunable_update_val (cur, valp, minp, maxp);
> }
>
> -/* Parse the tunable string VALSTRING. VALSTRING is a duplicated value,
> - where delimiters ':' are replaced with '\0', so string tunables are null
> - terminated. */
> -static void
> -parse_tunables (char *valstring)
> +struct tunable_toset_t
> +{
> + tunable_t *t;
> + const char *value;
> +};
> +
> +enum { tunables_list_size = array_length (tunable_list) };
> +
> +/* Parse the tunable string VALSTRING and set TUNABLES with the found tunables
> + and their respectibles values. VALSTRING is a duplicated values, where
s/respectibles/respective/
s/duplicated values/duplicated string/
> + delimiters ':' are replaced with '\0', so string tunables are null
> + terminated.
> + Return the number of tunables found (including 0 if the string is empty)
> + or -1 if for a ill-formatted definition. */
s/a ill-formatted/an ill-formatted/
> +static int
> +parse_tunables_string (char *valstring, struct tunable_toset_t *tunables)
> {
> if (valstring == NULL || *valstring == '\0')
> - return;
> + return 0;
>
> char *p = valstring;
> bool done = false;
> + int ntunables = 0;
>
> while (!done)
> {
> @@ -177,7 +189,7 @@ parse_tunables (char *valstring)
> /* If we reach the end of the string before getting a valid name-value
> pair, bail out. */
> if (*p == '\0')
> - break;
> + return -1;
>
> /* We did not find a valid name-value pair before encountering the
> colon. */
> @@ -190,30 +202,42 @@ parse_tunables (char *valstring)
> /* Skip the '='. */
> p++;
>
> - const char *value = p;
> + char *value = p;
>
> while (*p != '=' && *p != ':' && *p != '\0')
> p++;
>
> if (*p == '=')
> - break;
> + return -1;
> else if (*p == '\0')
> done = true;
> else
> *p++ = '\0';
>
> /* Add the tunable if it exists. */
> - for (size_t i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++)
> + for (size_t i = 0; i < tunables_list_size; i++)
> {
> tunable_t *cur = &tunable_list[i];
>
> if (tunable_is_name (cur->name, name))
> {
> - tunable_initialize (cur, value);
> + tunables[ntunables++] = (struct tunable_toset_t) { cur, value };
> break;
> }
> }
> }
> +
> + return ntunables;
> +}
> +
> +static void
> +parse_tunables (char *valstring)
> +{
> + struct tunable_toset_t tunables[tunables_list_size];
> + int ntunables = parse_tunables_string (valstring, tunables);
> +
> + for (int i = 0; i < ntunables; i++)
> + tunable_initialize (tunables[i].t, tunables[i].value);
> }
>
> /* Initialize the tunables list from the environment. For now we only use the
> @@ -240,7 +264,7 @@ __tunables_init (char **envp)
> continue;
> }
>
> - for (int i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++)
> + for (int i = 0; i < tunables_list_size; i++)
> {
> tunable_t *cur = &tunable_list[i];
>
> diff --git a/elf/tst-tunables.c b/elf/tst-tunables.c
> index 7fe9907e05..e1ad44f27c 100644
> --- a/elf/tst-tunables.c
> +++ b/elf/tst-tunables.c
> @@ -161,7 +161,7 @@ static const struct test_t
> 0,
> 0,
> },
> - /* If there is a ill-formatted key=value, everything after is also ignored. */
> + /* Ill-formatted tunables string is not parsed. */
> {
> "glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096:glibc.malloc.check=2",
> 0,
> @@ -186,13 +186,18 @@ static const struct test_t
> 0,
> 0,
> },
> - /* Valid tunables set before ill-formatted ones are set. */
> {
> "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096=4096",
> - 2,
> 0,
> 0,
> - }
> + 0,
> + },
> + {
> + "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096=4096",
> + 0,
> + 0,
> + 0,
> + },
> };
>
> static int
@@ -154,17 +154,29 @@ __tunable_set_val (tunable_id_t id, tunable_val_t *valp, tunable_num_t *minp,
do_tunable_update_val (cur, valp, minp, maxp);
}
-/* Parse the tunable string VALSTRING. VALSTRING is a duplicated value,
- where delimiters ':' are replaced with '\0', so string tunables are null
- terminated. */
-static void
-parse_tunables (char *valstring)
+struct tunable_toset_t
+{
+ tunable_t *t;
+ const char *value;
+};
+
+enum { tunables_list_size = array_length (tunable_list) };
+
+/* Parse the tunable string VALSTRING and set TUNABLES with the found tunables
+ and their respectibles values. VALSTRING is a duplicated values, where
+ delimiters ':' are replaced with '\0', so string tunables are null
+ terminated.
+ Return the number of tunables found (including 0 if the string is empty)
+ or -1 if for a ill-formatted definition. */
+static int
+parse_tunables_string (char *valstring, struct tunable_toset_t *tunables)
{
if (valstring == NULL || *valstring == '\0')
- return;
+ return 0;
char *p = valstring;
bool done = false;
+ int ntunables = 0;
while (!done)
{
@@ -177,7 +189,7 @@ parse_tunables (char *valstring)
/* If we reach the end of the string before getting a valid name-value
pair, bail out. */
if (*p == '\0')
- break;
+ return -1;
/* We did not find a valid name-value pair before encountering the
colon. */
@@ -190,30 +202,42 @@ parse_tunables (char *valstring)
/* Skip the '='. */
p++;
- const char *value = p;
+ char *value = p;
while (*p != '=' && *p != ':' && *p != '\0')
p++;
if (*p == '=')
- break;
+ return -1;
else if (*p == '\0')
done = true;
else
*p++ = '\0';
/* Add the tunable if it exists. */
- for (size_t i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++)
+ for (size_t i = 0; i < tunables_list_size; i++)
{
tunable_t *cur = &tunable_list[i];
if (tunable_is_name (cur->name, name))
{
- tunable_initialize (cur, value);
+ tunables[ntunables++] = (struct tunable_toset_t) { cur, value };
break;
}
}
}
+
+ return ntunables;
+}
+
+static void
+parse_tunables (char *valstring)
+{
+ struct tunable_toset_t tunables[tunables_list_size];
+ int ntunables = parse_tunables_string (valstring, tunables);
+
+ for (int i = 0; i < ntunables; i++)
+ tunable_initialize (tunables[i].t, tunables[i].value);
}
/* Initialize the tunables list from the environment. For now we only use the
@@ -240,7 +264,7 @@ __tunables_init (char **envp)
continue;
}
- for (int i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++)
+ for (int i = 0; i < tunables_list_size; i++)
{
tunable_t *cur = &tunable_list[i];
@@ -161,7 +161,7 @@ static const struct test_t
0,
0,
},
- /* If there is a ill-formatted key=value, everything after is also ignored. */
+ /* Ill-formatted tunables string is not parsed. */
{
"glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096:glibc.malloc.check=2",
0,
@@ -186,13 +186,18 @@ static const struct test_t
0,
0,
},
- /* Valid tunables set before ill-formatted ones are set. */
{
"glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096=4096",
- 2,
0,
0,
- }
+ 0,
+ },
+ {
+ "glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096=4096",
+ 0,
+ 0,
+ 0,
+ },
};
static int