scsi: sr: Sanity check returned mode data (a00a7862) · Commits · 戴 / test

Kefeng Wang discovered that old versions of the QEMU CD driver would return mangled mode data causing us to walk off the end of the buffer in an attempt to parse it. Sanity check the returned mode sense data. Cc: <stable@vger.kernel.org> Reported-by:

Kefeng Wang <wangkefeng.wang@huawei.com> Tested-by:

Kefeng Wang <wangkefeng.wang@huawei.com> Signed-off-by:

Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sr.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -836,6 +836,7 @@ static void get_capabilities(struct scsi_cd *cd)
		unsigned char *buffer;
		struct scsi_mode_data data;
		struct scsi_sense_hdr sshdr;
		unsigned int ms_len = 128;
		int rc, n;

		static const char *loadmech[] =
		@@ -862,10 +863,11 @@ static void get_capabilities(struct scsi_cd *cd)
		scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);

		/* ask for mode page 0x2a */
		rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, 128,
		rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, ms_len,
		SR_TIMEOUT, 3, &data, NULL);

		if (!scsi_status_is_good(rc)) {
		if (!scsi_status_is_good(rc) \|\| data.length > ms_len \|\|
		data.header_length + data.block_descriptor_length > data.length) {
		/* failed, drive doesn't have capabilities mode page */
		cd->cdi.speed = 1;
		cd->cdi.mask \|= (CDC_CD_R \| CDC_CD_RW \| CDC_DVD_R \|

Admin message