[PATCH AUTOSEL 6.1 8/9] kconfig: fix memory leak from range properties

Sasha Levin
2023-11-22T15:35:01Z

From: Masahiro Yamada <masahiroy@kernel.org>

[ Upstream commit ae1eff0349f2e908fc083630e8441ea6dc434dc0 ]

Currently, sym_validate_range() duplicates the range string using
xstrdup(), which is overwritten by a subsequent sym_calc_value() call.
It results in a memory leak.

Instead, only the pointer should be copied.

Below is a test case, with a summary from Valgrind.

[Test Kconfig]

config FOO
int "foo"
range 10 20

[Test .config]

CONFIG_FOO=0

[Before]

LEAK SUMMARY:
definitely lost: 3 bytes in 1 blocks
indirectly lost: 0 bytes in 0 blocks
possibly lost: 0 bytes in 0 blocks
still reachable: 17,465 bytes in 21 blocks
suppressed: 0 bytes in 0 blocks

[After]

LEAK SUMMARY:
definitely lost: 0 bytes in 0 blocks
indirectly lost: 0 bytes in 0 blocks
possibly lost: 0 bytes in 0 blocks
still reachable: 17,462 bytes in 20 blocks
suppressed: 0 bytes in 0 blocks

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
scripts/kconfig/symbol.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index 0572330bf8a78..a76925b46ce63 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -122,9 +122,9 @@ static long long sym_get_range_val(struct symbol *sym, int base)
static void sym_validate_range(struct symbol *sym)
{
struct property *prop;
+ struct symbol *range_sym;
int base;
long long val, val2;
- char str[64];

switch (sym->type) {
case S_INT:
@@ -140,17 +140,15 @@ static void sym_validate_range(struct symbol *sym)
if (!prop)
return;
val = strtoll(sym->curr.val, NULL, base);
- val2 = sym_get_range_val(prop->expr->left.sym, base);
+ range_sym = prop->expr->left.sym;
+ val2 = sym_get_range_val(range_sym, base);
if (val >= val2) {
- val2 = sym_get_range_val(prop->expr->right.sym, base);
+ range_sym = prop->expr->right.sym;
+ val2 = sym_get_range_val(range_sym, base);
if (val <= val2)
return;
}
- if (sym->type == S_INT)
- sprintf(str, "%lld", val2);
- else
- sprintf(str, "0x%llx", val2);
- sym->curr.val = xstrdup(str);
+ sym->curr.val = range_sym->curr.val;
}

static void sym_set_changed(struct symbol *sym)
--
2.42.0