From a52e62a329f27e5f0a35402cdbd194c9ed4542a7 Mon Sep 17 00:00:00 2001

From: Evgeny Vereshchagin <evvers@ya.ru>

Date: Wed, 7 Jun 2017 04:47:47 +0300

Subject: [PATCH] udev: stop freeing value after using it for setting sysattr

 (#6094)

This prevents udev from double-freeing and crashing.

See https://github.com/systemd/systemd/issues/6040#issuecomment-306589836

==351== Invalid free() / delete / delete[] / realloc()

==351==    at 0x4C2C14B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)

==351==    by 0x13CBE8: hashmap_clear_free_free (hashmap.c:900)

==351==    by 0x13CBE8: hashmap_free_free_free (hashmap.c:852)

==351==    by 0x147F4F: sd_device_unref (sd-device.c:88)

==351==    by 0x130CCC: udev_device_unref (libudev-device.c:552)

==351==    by 0x130CD5: udev_device_unref (libudev-device.c:553)

==351==    by 0x11FBBB: worker_spawn (udevd.c:488)

==351==    by 0x1216E5: event_run (udevd.c:584)

==351==    by 0x1216E5: event_queue_start (udevd.c:823)

==351==    by 0x122213: on_uevent (udevd.c:927)

==351==    by 0x141F2F: source_dispatch (sd-event.c:2272)

==351==    by 0x142D52: sd_event_dispatch (sd-event.c:2631)

==351==    by 0x142D52: sd_event_run (sd-event.c:2690)

==351==    by 0x142D52: sd_event_loop (sd-event.c:2710)

==351==    by 0x1159CB: run (udevd.c:1643)

==351==    by 0x1159CB: main (udevd.c:1772)

==351==  Address 0x81745b0 is 0 bytes inside a block of size 1 free'd

==351==    at 0x4C2C14B: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)

==351==    by 0x1447F0: freep (alloc-util.h:57)

==351==    by 0x1447F0: sd_device_set_sysattr_value (sd-device.c:1859)

==351==    by 0x132081: udev_device_set_sysattr_value (libudev-device.c:849)

==351==    by 0x12E777: set_trackpoint_sensitivity (udev-builtin-keyboard.c:180)

==351==    by 0x12E777: builtin_keyboard.lto_priv.170 (udev-builtin-keyboard.c:263)

==351==    by 0x14D03F: udev_builtin_run.constprop.75 (udev-builtin.c:133)

==351==    by 0x11FAEB: udev_event_execute_run (udev-event.c:957)

==351==    by 0x11FAEB: worker_spawn (udevd.c:461)

==351==    by 0x1216E5: event_run (udevd.c:584)

==351==    by 0x1216E5: event_queue_start (udevd.c:823)

==351==    by 0x122213: on_uevent (udevd.c:927)

==351==    by 0x141F2F: source_dispatch (sd-event.c:2272)

==351==    by 0x142D52: sd_event_dispatch (sd-event.c:2631)

==351==    by 0x142D52: sd_event_run (sd-event.c:2690)

==351==    by 0x142D52: sd_event_loop (sd-event.c:2710)

==351==    by 0x1159CB: run (udevd.c:1643)

==351==    by 0x1159CB: main (udevd.c:1772)

==351==  Block was alloc'd at

==351==    at 0x4C2CF35: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)

==351==    by 0x144853: sd_device_set_sysattr_value (sd-device.c:1888)

==351==    by 0x132081: udev_device_set_sysattr_value (libudev-device.c:849)

==351==    by 0x12E777: set_trackpoint_sensitivity (udev-builtin-keyboard.c:180)

==351==    by 0x12E777: builtin_keyboard.lto_priv.170 (udev-builtin-keyboard.c:263)

==351==    by 0x14D03F: udev_builtin_run.constprop.75 (udev-builtin.c:133)

==351==    by 0x11FAEB: udev_event_execute_run (udev-event.c:957)

==351==    by 0x11FAEB: worker_spawn (udevd.c:461)

==351==    by 0x1216E5: event_run (udevd.c:584)

==351==    by 0x1216E5: event_queue_start (udevd.c:823)

==351==    by 0x122213: on_uevent (udevd.c:927)

==351==    by 0x141F2F: source_dispatch (sd-event.c:2272)

==351==    by 0x142D52: sd_event_dispatch (sd-event.c:2631)

==351==    by 0x142D52: sd_event_run (sd-event.c:2690)

==351==    by 0x142D52: sd_event_loop (sd-event.c:2710)

==351==    by 0x1159CB: run (udevd.c:1643)

==351==    by 0x1159CB: main (udevd.c:1772)

(cherry picked from commit 3bd82598a1b48d27b17baf4b43bdf1104bcb1021)

---

 src/libsystemd/sd-device/sd-device.c | 1 +

 1 file changed, 1 insertion(+)

diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c

index 04ead29338..81d8d61ba9 100644

--- a/src/libsystemd/sd-device/sd-device.c

+++ b/src/libsystemd/sd-device/sd-device.c

@@ -1892,6 +1892,7 @@ _public_ int sd_device_set_sysattr_value(sd_device *device, const char *sysattr,

                 r = device_add_sysattr_value(device, sysattr, value);

                 if (r < 0)

                         return r;

+                value = NULL;

                 return -ENXIO;

         }