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scsi: target: pscsi: Fix possible null-pointer dereference in pscsi_complete_cmd()

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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.

Link: https://lore.kernel.org/r/20210810040414.248167-1-islituo@gmail.com
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Reviewed-by: Bodo Stroesser <bostroesser@gmail.com>
Signed-off-by: Tuo Li <islituo@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Tuo Li 2021-08-09 21:04:13 -07:00 committed by Martin K. Petersen
parent 4c7b6ea336
commit 0f99792c01
1 changed files with 9 additions and 9 deletions
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18
drivers/target/target_core_pscsi.c
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@ -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: