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hw/scsi/spapr_vscsi: Prevent buffer overflow

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Depending on the length of sense data, vscsi_send_rsp() can
overrun the buffer size.
Do not copy more than SRP_MAX_IU_DATA_LEN bytes, and assert
that vscsi_send_iu() is always called with a size in range.

Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200305121253.19078-7-philmd@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Philippe Mathieu-Daudé 2020-03-05 13:12:52 +01:00 committed by David Gibson
parent ff78b728f6
commit 13a5490536
1 changed files with 10 additions and 3 deletions
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13
hw/scsi/spapr_vscsi.c
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@ -55,6 +55,8 @@
#define VSCSI_MAX_SECTORS 4096
#define VSCSI_REQ_LIMIT 24
/* Maximum size of a IU payload */
#define SRP_MAX_IU_DATA_LEN (SRP_MAX_IU_LEN - sizeof(union srp_iu))
#define SRP_RSP_SENSE_DATA_LEN 18
#define SRP_REPORT_LUNS_WLUN 0xc10100000000000ULL
@ -181,6 +183,8 @@ static int vscsi_send_iu(VSCSIState *s, vscsi_req *req,
{
long rc, rc1;
assert(length <= SRP_MAX_IU_LEN);
/* First copy the SRP */
rc = spapr_vio_dma_write(&s->vdev, req->crq.s.IU_data_ptr,
&req->viosrp_iu_buf, length);
@ -266,10 +270,12 @@ static int vscsi_send_rsp(VSCSIState *s, vscsi_req *req,
if (status) {
iu->srp.rsp.sol_not = (sol_not & 0x04) >> 2;
if (req->senselen) {
int sense_data_len = MIN(req->senselen, SRP_MAX_IU_DATA_LEN);
iu->srp.rsp.flags |= SRP_RSP_FLAG_SNSVALID;
iu->srp.rsp.sense_data_len = cpu_to_be32(req->senselen);
memcpy(iu->srp.rsp.data, req->sense, req->senselen);
total_len += req->senselen;
iu->srp.rsp.sense_data_len = cpu_to_be32(sense_data_len);
memcpy(iu->srp.rsp.data, req->sense, sense_data_len);
total_len += sense_data_len;
}
} else {
iu->srp.rsp.sol_not = (sol_not & 0x02) >> 1;
@ -896,6 +902,7 @@ static int vscsi_process_tsk_mgmt(VSCSIState *s, vscsi_req *req)
}
/* Compose the response here as */
QEMU_BUILD_BUG_ON(SRP_MAX_IU_DATA_LEN < 4);
memset(iu, 0, sizeof(struct srp_rsp) + 4);
iu->srp.rsp.opcode = SRP_RSP;
iu->srp.rsp.req_lim_delta = cpu_to_be32(1);