From 519940a872c5594ecf9236dd391512a9f92400f6 Mon Sep 17 00:00:00 2001 From: Roxana Nicolescu Date: Wed, 6 May 2026 10:55:53 +0200 Subject: [PATCH] scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count() jira VULN-176313 cve CVE-2026-23193 commit-author Maurizio Lombardi commit 84dc6037390b8607c5551047d3970336cb51ba9a In iscsit_dec_session_usage_count(), the function calls complete() while holding the sess->session_usage_lock. Similar to the connection usage count logic, the waiter signaled by complete() (e.g., in the session release path) may wake up and free the iscsit_session structure immediately. This creates a race condition where the current thread may attempt to execute spin_unlock_bh() on a session structure that has already been deallocated, resulting in a KASAN slab-use-after-free. To resolve this, release the session_usage_lock before calling complete() to ensure all dereferences of the sess pointer are finished before the waiter is allowed to proceed with deallocation. Signed-off-by: Maurizio Lombardi Reported-by: Zhaojuan Guo Reviewed-by: Mike Christie Link: https://patch.msgid.link/20260112165352.138606-3-mlombard@redhat.com Signed-off-by: Martin K. Petersen (cherry picked from commit 84dc6037390b8607c5551047d3970336cb51ba9a) Signed-off-by: Roxana Nicolescu --- drivers/target/iscsi/iscsi_target_util.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c index 8d9f21372b674..f646aa92160bf 100644 --- a/drivers/target/iscsi/iscsi_target_util.c +++ b/drivers/target/iscsi/iscsi_target_util.c @@ -785,8 +785,11 @@ void iscsit_dec_session_usage_count(struct iscsit_session *sess) spin_lock_bh(&sess->session_usage_lock); sess->session_usage_count--; - if (!sess->session_usage_count && sess->session_waiting_on_uc) + if (!sess->session_usage_count && sess->session_waiting_on_uc) { + spin_unlock_bh(&sess->session_usage_lock); complete(&sess->session_waiting_on_uc_comp); + return; + } spin_unlock_bh(&sess->session_usage_lock); }