From: Prasad J Pandit <p...@fedoraproject.org> When executing script in lsi_execute_script(), the LSI scsi adapter emulator advances 's->dsp' index to read next opcode. This can lead to an infinite loop if the next opcode is empty. Exit such loop after reading 10k empty opcodes.
Reported-by: Bugs SysSec <bugs-sys...@rub.de> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/scsi/lsi53c895a.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) Update v3: raise an illegal instruction interrupt and exit -> https://lists.gnu.org/archive/html/qemu-devel/2019-08/msg01427.html diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c index 10468c1ec1..e703ef4c9d 100644 --- a/hw/scsi/lsi53c895a.c +++ b/hw/scsi/lsi53c895a.c @@ -185,6 +185,9 @@ static const char *names[] = { /* Flag set if this is a tagged command. */ #define LSI_TAG_VALID (1 << 16) +/* Maximum instructions to process. */ +#define LSI_MAX_INSN 10000 + typedef struct lsi_request { SCSIRequest *req; uint32_t tag; @@ -1132,7 +1135,13 @@ static void lsi_execute_script(LSIState *s) s->istat1 |= LSI_ISTAT1_SRUN; again: - insn_processed++; + if (++insn_processed > LSI_MAX_INSN) { + trace_lsi_execute_script_tc_illegal(); + lsi_script_dma_interrupt(s, LSI_DSTAT_IID); + lsi_disconnect(s); + trace_lsi_execute_script_stop(); + return; + } insn = read_dword(s, s->dsp); if (!insn) { /* If we receive an empty opcode increment the DSP by 4 bytes -- 2.21.0
