From: Tuo Li islituo@gmail.com
[ Upstream commit 0f99792c01d1d6d35b86e850e9ccadd98d6f3e0c ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/target/target_core_pscsi.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index 0ce3697ecbd7..cca8404648ba 100644 --- a/drivers/target/target_core_pscsi.c +++ b/drivers/target/target_core_pscsi.c @@ -631,17 +631,17 @@ static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg, 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: