| Message ID | 20210810040414.248167-1-islituo@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] scsi: target: pscsi: Fix possible null-pointer dereference in pscsi_complete_cmd() | expand |
Tuo, > The return value of transport_kmap_data_sg() is assigned to the variable > buf: Applied to 5.15/scsi-staging, thanks! -- Martin K. Petersen Oracle Linux Engineering
On Mon, 9 Aug 2021 21:04:13 -0700, Tuo Li wrote: > The return value of transport_kmap_data_sg() is assigned to the variable > buf: > buf = transport_kmap_data_sg(cmd); > > And then it is checked: > if (!buf) { > > [...] Applied to 5.15/scsi-queue, thanks! [1/1] scsi: target: pscsi: Fix possible null-pointer dereference in pscsi_complete_cmd() https://git.kernel.org/mkp/scsi/c/0f99792c01d1 -- Martin K. Petersen Oracle Linux Engineering
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 2629d2ef3970..75ef52f008ff 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -620,17 +620,17 @@ static void pscsi_complete_cmd(struct se_cmd *cmd, u8 scsi_status, buf = transport_kmap_data_sg(cmd); if (!buf) { ; /* XXX: TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE */ - } - - if (cdb[0] == MODE_SENSE_10) { - if (!(buf[3] & 0x80)) - buf[3] |= 0x80; } else { - if (!(buf[2] & 0x80)) - buf[2] |= 0x80; - } + if (cdb[0] == MODE_SENSE_10) { + if (!(buf[3] & 0x80)) + buf[3] |= 0x80; + } else { + if (!(buf[2] & 0x80)) + buf[2] |= 0x80; + } - transport_kunmap_data_sg(cmd); + transport_kunmap_data_sg(cmd); + } } } after_mode_sense:
The return value of transport_kmap_data_sg() is assigned to the variable buf: buf = transport_kmap_data_sg(cmd); And then it is checked: if (!buf) { This indicates that buf can be NULL. However, it is dereferenced in the following statements: if (!(buf[3] & 0x80)) buf[3] |= 0x80; if (!(buf[2] & 0x80)) buf[2] |= 0x80; To fix these possible null-pointer dereferences, dereference buf and call transport_kunmap_data_sg() only when buf is not NULL. Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Signed-off-by: Tuo Li <islituo@gmail.com> --- v2: * Put transport_kunmap_data_sg() into the else-branch of the if (!bug). Thank Bodo Stroesser for helpful advice. --- drivers/target/target_core_pscsi.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)