hw/scsi/lsi53c895a: add missing decrement of reentrancy counter

When the maximum count of SCRIPTS instructions is reached, the code
stops execution and returns, but fails to decrement the reentrancy
counter. This effectively renders the SCSI controller unusable
because on next entry the reentrancy counter is still above the limit.

This bug was seen on HP-UX 10.20 which seems to trigger SCRIPTS
loops.

Fixes: b987718bbb ("hw/scsi/lsi53c895a: Fix reentrancy issues in the LSI controller (CVE-2023-0330)")
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Message-ID: <20240128202214.2644768-1-svens@stackframe.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 8b09b7fe47082c69295a0fc0cc01b041b6385025)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c
index 905f5ef237bd6ae36d928fccd5c2bcd92358181d..c7a3964b5f7392c0345d721fc4613c83208ebfd9 100644 (file)
--- a/hw/scsi/lsi53c895a.c
+++ b/hw/scsi/lsi53c895a.c
@@ -1167,6 +1167,7 @@ again:
         lsi_script_scsi_interrupt(s, LSI_SIST0_UDC, 0);
         lsi_disconnect(s);
         trace_lsi_execute_script_stop();
+        reentrancy_level--;
         return;
     }
     insn = read_dword(s, s->dsp);