| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 88/96] target/user: Fix use-after-free of tcmu_cmds if they are expired | Date | Fri, 6 Jan 2017 22:44:16 +0100 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Andy Grover <agrover@redhat.com>
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 <bgly@us.ibm.com> Tested-by: Bryant G Ly <bgly@us.ibm.com> Signed-off-by: Andy Grover <agrover@redhat.com> Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/target/target_core_user.c | 2 -- 1 file changed, 2 deletions(-)
--- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -682,8 +682,6 @@ static int tcmu_check_expired_cmd(int id target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION); cmd->se_cmd = NULL; - kmem_cache_free(tcmu_cmd_cache, cmd); - return 0; }
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