[PATCH 4.15 014/128] scsi: sd_zbc: Fix potential memory leak

Greg Kroah-Hartman
2018-03-16T15:22:35Z

From: Damien Le Moal <damien.lemoal@wdc.com>

commit 4b433924b2755a94f99258c178684a0e05c344de upstream.

Rework sd_zbc_check_zone_size() to avoid a memory leak due to an early
return if sd_zbc_report_zones() fails.

Reported-by: David.butterfield <david.butterfield@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Cc: stable@vger.kernel.org
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/sd_zbc.c | 35 +++++++++++++++--------------------
1 file changed, 15 insertions(+), 20 deletions(-)

--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -486,7 +486,7 @@ static int sd_zbc_check_capacity(struct
*/
static int sd_zbc_check_zone_size(struct scsi_disk *sdkp)
{
- u64 zone_blocks;
+ u64 zone_blocks = 0;
sector_t block = 0;
unsigned char *buf;
unsigned char *rec;
@@ -504,10 +504,8 @@ static int sd_zbc_check_zone_size(struct

/* Do a report zone to get the same field */
ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0);
- if (ret) {
- zone_blocks = 0;
- goto out;
- }
+ if (ret)
+ goto out_free;

same = buf[4] & 0x0f;
if (same > 0) {
@@ -547,7 +545,7 @@ static int sd_zbc_check_zone_size(struct
ret = sd_zbc_report_zones(sdkp, buf,
SD_ZBC_BUF_SIZE, block);
if (ret)
- return ret;
+ goto out_free;
}

} while (block < sdkp->capacity);
@@ -555,35 +553,32 @@ static int sd_zbc_check_zone_size(struct
zone_blocks = sdkp->zone_blocks;

out:
- kfree(buf);
-
if (!zone_blocks) {
if (sdkp->first_scan)
sd_printk(KERN_NOTICE, sdkp,
"Devices with non constant zone "
"size are not supported\n");
- return -ENODEV;
- }
-
- if (!is_power_of_2(zone_blocks)) {
+ ret = -ENODEV;
+ } else if (!is_power_of_2(zone_blocks)) {
if (sdkp->first_scan)
sd_printk(KERN_NOTICE, sdkp,
"Devices with non power of 2 zone "
"size are not supported\n");
- return -ENODEV;
- }
-
- if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
+ ret = -ENODEV;
+ } else if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
if (sdkp->first_scan)
sd_printk(KERN_NOTICE, sdkp,
"Zone size too large\n");
- return -ENODEV;
+ ret = -ENODEV;
+ } else {
+ sdkp->zone_blocks = zone_blocks;
+ sdkp->zone_shift = ilog2(zone_blocks);
}

- sdkp->zone_blocks = zone_blocks;
- sdkp->zone_shift = ilog2(zone_blocks);
+out_free:
+ kfree(buf);

- return 0;
+ return ret;
}

static int sd_zbc_setup(struct scsi_disk *sdkp)