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| author | David Herrmann <dh.herrmann@gmail.com> | 2013-08-30 15:50:41 +0200 |
|---|---|---|
| committer | Kay Sievers <kay@vrfy.org> | 2013-09-04 17:58:56 +0200 |
| commit | f9e84da678cc28998fb04bf5ba326d91fc2850fa (patch) | |
| tree | 54efd71f56e216018693fab20eb285538228a86c /src/libudev/libudev-enumerate.c | |
| parent | c851f34ba1cb379d3b3fc06a8421051fd9d0394d (diff) | |
| download | systemd-f9e84da678cc28998fb04bf5ba326d91fc2850fa.tar.gz | |
libudev: enumerate: fix NULL-deref for subsystem-matches
udev_device_get_subsystem() may return NULL if no subsystem could be
figured out by libudev. This might be due to OOM or if the device
disconnected between the udev_device_new() call and
udev_device_get_subsystem(). Therefore, we need to handle subsystem==NULL
safely.
Instead of testing for it in each helper, we treat subsystem==NULL as
empty subsystem in match_subsystem().
Backtrace of udev_enumerate with an input-device disconnecting in exactly
this time-frame:
(gdb) bt
#0 0x00007ffff569dc24 in strnlen () from /usr/lib/libc.so.6
#1 0x00007ffff56d9e04 in fnmatch@@GLIBC_2.2.5 () from /usr/lib/libc.so.6
#2 0x00007ffff5beb83d in match_subsystem (udev_enumerate=0x7a05f0, subsystem=0x0) at src/libudev/libudev-enumerate.c:727
#3 0x00007ffff5bebb30 in parent_add_child (enumerate=enumerate@entry=0x7a05f0, path=<optimized out>) at src/libudev/libudev-enumerate.c:834
#4 0x00007ffff5bebc3f in parent_crawl_children (enumerate=enumerate@entry=0x7a05f0, path=0x7a56b0 "/sys/devices/<shortened>/input/input97", maxdepth=maxdepth@entry=254) at src/libudev/libudev-enumerate.c:866
#5 0x00007ffff5bebc54 in parent_crawl_children (enumerate=enumerate@entry=0x7a05f0, path=0x79e8c0 "/sys/devices/<shortened>/input", maxdepth=maxdepth@entry=255) at src/libudev/libudev-enumerate.c:868
#6 0x00007ffff5bebc54 in parent_crawl_children (enumerate=enumerate@entry=0x7a05f0, path=path@entry=0x753190 "/sys/devices/<shortened>", maxdepth=maxdepth@entry=256) at src/libudev/libudev-enumerate.c:868
#7 0x00007ffff5bec7df in scan_devices_children (enumerate=0x7a05f0) at src/libudev/libudev-enumerate.c:882
#8 udev_enumerate_scan_devices (udev_enumerate=udev_enumerate@entry=0x7a05f0) at src/libudev/libudev-enumerate.c:919
#9 0x00007ffff5df8777 in <random_caller> () at some/file.c:181
Diffstat (limited to 'src/libudev/libudev-enumerate.c')
| -rw-r--r-- | src/libudev/libudev-enumerate.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/libudev/libudev-enumerate.c b/src/libudev/libudev-enumerate.c index b96e5b278f..385829d464 100644 --- a/src/libudev/libudev-enumerate.c +++ b/src/libudev/libudev-enumerate.c @@ -721,6 +721,8 @@ static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *s { struct udev_list_entry *list_entry; + subsystem = subsystem ? : ""; + udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) { if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0) return false; |