From: Andy Grover Date: Tue, 22 Nov 2016 00:35:30 +0000 (-0800) Subject: target/user: Fix use-after-free of tcmu_cmds if they are expired X-Git-Tag: v4.4.41~4 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e321f384d8a58e546469cc8d3ca04257ef474d4c;p=thirdparty%2Fkernel%2Fstable.git target/user: Fix use-after-free of tcmu_cmds if they are expired commit d0905ca757bc40bd1ebc261a448a521b064777d7 upstream. Don't free the cmd in tcmu_check_expired_cmd, it's still referenced by an entry in our cmd_id->cmd idr. If userspace ever resumes processing, tcmu_handle_completions() will use the now-invalid cmd pointer. Instead, don't free cmd. It will be freed by tcmu_handle_completion() if userspace ever recovers, or tcmu_free_device if not. Reported-by: Bryant G Ly Tested-by: Bryant G Ly Signed-off-by: Andy Grover Signed-off-by: Bart Van Assche Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index 5e6d6cb348fc1..a7d30e894cab2 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -645,8 +645,6 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); cmd->se_cmd = NULL; - kmem_cache_free(tcmu_cmd_cache, cmd); - return 0; }