From: Tejun Heo Date: Wed, 20 Feb 2013 23:24:12 +0000 (-0800) Subject: posix-timer: Don't call idr_find() with out-of-range ID X-Git-Tag: v3.9-rc1~61^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e182bb38d7db7494fa5dcd82da17fe0dedf60ecf;p=pandora-kernel.git posix-timer: Don't call idr_find() with out-of-range ID When idr_find() was fed a negative ID, it used to look up the ID ignoring the sign bit before recent ("idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.c") patch. Now a negative ID triggers a WARN_ON_ONCE(). __lock_timer() feeds timer_id from userland directly to idr_find() without sanitizing it which can trigger the above malfunctions. Add a range check on @timer_id before invoking idr_find() in __lock_timer(). While timer_t is defined as int by all archs at the moment, Andrew worries that it may be defined as a larger type later on. Make the test cover larger integers too so that it at least is guaranteed to not return the wrong timer. Note that WARN_ON_ONCE() in idr_find() on id < 0 is transitional precaution while moving away from ignoring MSB. Once it's gone we can remove the guard as long as timer_t isn't larger than int. Signed-off-by: Tejun Heo nnn Reported-by: Sasha Levin Cc: Andrew Morton Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20130220232412.GL3570@htj.dyndns.org Signed-off-by: Thomas Gleixner --- Reading git-diff-tree failed