From 396088c69b902ddd4b4437a9bb9e9c73e603b278 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 7 Sep 2012 17:30:39 +0200 Subject: [PATCH] target: fix truncation of mode data, support zero allocation length The offset was not bumped back to the full size after writing the header of the MODE SENSE response, so the last 1 or 2 bytes were not copied. On top of this, support zero-length requests by checking for the return value of transport_kmap_data_sg. Testcase: sg_raw -r20 /dev/sdb 5a 00 0a 00 00 00 00 00 14 00 last byte should be 0x1e it is 0x00 without the patch it is correct with the patch Signed-off-by: Paolo Bonzini Cc: stable@vger.kernel.org Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_spc.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index e27701b83641..f23dda3811c9 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -784,7 +784,7 @@ static int spc_emulate_modesense(struct se_cmd *cmd) unsigned char *rbuf; int type = dev->transport->get_device_type(dev); int ten = (cmd->t_task_cdb[0] == MODE_SENSE_10); - int offset = ten ? 8 : 4; + u32 offset = ten ? 8 : 4; int length = 0; unsigned char buf[SE_MODE_PAGE_BUF]; @@ -817,6 +817,7 @@ static int spc_emulate_modesense(struct se_cmd *cmd) offset -= 2; buf[0] = (offset >> 8) & 0xff; buf[1] = offset & 0xff; + offset += 2; if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) || (cmd->se_deve && @@ -826,13 +827,10 @@ static int spc_emulate_modesense(struct se_cmd *cmd) if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) && (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0)) spc_modesense_dpofua(&buf[3], type); - - if ((offset + 2) > cmd->data_length) - offset = cmd->data_length; - } else { offset -= 1; buf[0] = offset & 0xff; + offset += 1; if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) || (cmd->se_deve && @@ -842,14 +840,13 @@ static int spc_emulate_modesense(struct se_cmd *cmd) if ((dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0) && (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0)) spc_modesense_dpofua(&buf[2], type); - - if ((offset + 1) > cmd->data_length) - offset = cmd->data_length; } rbuf = transport_kmap_data_sg(cmd); - memcpy(rbuf, buf, offset); - transport_kunmap_data_sg(cmd); + if (rbuf) { + memcpy(rbuf, buf, min(offset, cmd->data_length)); + transport_kunmap_data_sg(cmd); + } target_complete_cmd(cmd, GOOD); return 0; -- 2.39.5