hw/gpio/pca9554: Avoid leak in pca9554_set_pin()

In pca9554_set_pin() we have a string property which we parse in
order to set some non-string fields in the device state.  So we call
visit_type_str(), passing it the address of the local variable
state_str.

visit_type_str() will allocate a new copy of the string; we
never free this string, so the result is a memory leak, detected
by ASAN during a "make check" run:

Direct leak of 5 byte(s) in 1 object(s) allocated from:
    #0 0x5d605212ede3 in malloc (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/qemu-system-arm+0x21f1de3) (
BuildId: 3d5373c89317f58bfcd191a33988c7347714be14)
    #1 0x7f7edea57b09 in g_malloc (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x62b09) (BuildId: 1eb6131419edb83b2178b68282
9a6913cf682d75)
    #2 0x7f7edea6d4d8 in g_strdup (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x784d8) (BuildId: 1eb6131419edb83b2178b68282
9a6913cf682d75)
    #3 0x5d6055289a91 in g_strdup_inline /usr/include/glib-2.0/glib/gstrfuncs.h:321:10
    #4 0x5d6055289a91 in qobject_input_type_str /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../qapi/qo
bject-input-visitor.c:542:12
    #5 0x5d605528479c in visit_type_str /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../qapi/qapi-visit
-core.c:349:10
    #6 0x5d60528bdd87 in pca9554_set_pin /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../hw/gpio/pca9554.c:179:10
    #7 0x5d60549bcbbb in object_property_set /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../qom/object.c:1450:5
    #8 0x5d60549d2055 in object_property_set_qobject /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../qom/qom-qobject.c:28:10
    #9 0x5d60549bcdf1 in object_property_set_str /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../qom/object.c:1458:15
    #10 0x5d605439d077 in gb200nvl_bmc_i2c_init /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../hw/arm/aspeed.c:1267:5
    #11 0x5d60543a3bbc in aspeed_machine_init /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/arm-asan/../../hw/arm/aspeed.c:493:9

Make the state_str g_autofree, so that we will always free
it, on both error-exit and success codepaths.

Cc: qemu-stable@nongnu.org
Fixes: de0c7d543bca ("misc: Add a pca9554 GPIO device model")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Glenn Miles <milesg@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <20250821154459.2417976-1-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

diff --git a/hw/gpio/pca9554.c b/hw/gpio/pca9554.c
index de3f883aee933297059df247642c8def175633f8..eac0d23be34a59b301327af2a17034f4539f2377 100644 (file)
--- a/hw/gpio/pca9554.c
+++ b/hw/gpio/pca9554.c
@@ -174,7 +174,7 @@ static void pca9554_set_pin(Object *obj, Visitor *v, const char *name,
     PCA9554State *s = PCA9554(obj);
     int pin, rc, val;
     uint8_t state, mask;
-    char *state_str;
+    g_autofree char *state_str = NULL;
 
     if (!visit_type_str(v, name, &state_str, errp)) {
         return;