2021-03-11 10:39:42

by Colin King

Subject: [PATCH][next] scsi: sg: Fix use of pointer sfp after it has been kfree'd

From: Colin Ian King <[email protected]>

Currently SG_LOG is referencing sfp after it has been kfree'd which
is probably a bad thing to do. Fix this by kfree'ing sfp after
SG_LOG.

Addresses-Coverity: ("Use after free")
Fixes: af1fc95db445 ("scsi: sg: Replace rq array with xarray")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/scsi/sg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 2d4bbc1a1727..79f05afa4407 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -3799,10 +3799,10 @@ sg_add_sfp(struct sg_device *sdp)
if (rbuf_len > 0) {
srp = sg_build_reserve(sfp, rbuf_len);
if (IS_ERR(srp)) {
- kfree(sfp);
err = PTR_ERR(srp);
SG_LOG(1, sfp, "%s: build reserve err=%ld\n", __func__,
-err);
+ kfree(sfp);
return ERR_PTR(err);
}
if (srp->sgat_h.buflen < rbuf_len) {
--
2.30.2

2021-03-11 17:19:32

by Douglas Gilbert

Subject: Re: [PATCH][next] scsi: sg: Fix use of pointer sfp after it has been kfree'd

On 2021-03-11 5:37 a.m., Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> Currently SG_LOG is referencing sfp after it has been kfree'd which
> is probably a bad thing to do. Fix this by kfree'ing sfp after
> SG_LOG.
>
> Addresses-Coverity: ("Use after free")
> Fixes: af1fc95db445 ("scsi: sg: Replace rq array with xarray")
> Signed-off-by: Colin Ian King <[email protected]>

Acked-by: Douglas Gilbert <[email protected]>

Thanks.

> ---
> drivers/scsi/sg.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 2d4bbc1a1727..79f05afa4407 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -3799,10 +3799,10 @@ sg_add_sfp(struct sg_device *sdp)
> if (rbuf_len > 0) {
> srp = sg_build_reserve(sfp, rbuf_len);
> if (IS_ERR(srp)) {
> - kfree(sfp);
> err = PTR_ERR(srp);
> SG_LOG(1, sfp, "%s: build reserve err=%ld\n", __func__,
> -err);
> + kfree(sfp);
> return ERR_PTR(err);
> }
> if (srp->sgat_h.buflen < rbuf_len) {
>