linux-kernel - [ 29/76] target: support zero allocation length in INQUIRY

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 18 Oct 2012 19:46:53 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	alan@...rguk.ukuu.org.uk, Paolo Bonzini <pbonzini@...hat.com>,
	Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: [ 29/76] target: support zero allocation length in INQUIRY

3.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Paolo Bonzini <pbonzini@...hat.com>

commit ffe7b0e9326d9c68f5688bef691dd49f1e0d3651 upstream.

INQUIRY processing already uses an on-heap bounce buffer for loopback,
but not for other fabrics.  Switch this to a cheaper on-stack bounce
buffer, similar to the one used by MODE SENSE and REQUEST SENSE, and
use it unconditionally.  With this in place, zero allocation length is
handled simply by checking the return address of transport_kmap_data_sg.

Testcase: sg_raw /dev/sdb 12 00 83 00 00 00
    should fail with ILLEGAL REQUEST / INVALID FIELD IN CDB sense
    does not fail without the patch
    fails correctly with the series

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Nicholas Bellinger <nab@...ux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/target/target_core_spc.c |   31 ++++++-------------------------
 1 file changed, 6 insertions(+), 25 deletions(-)

--- a/drivers/target/target_core_spc.c
+++ b/drivers/target/target_core_spc.c
@@ -600,30 +600,11 @@ static int spc_emulate_inquiry(struct se
 {
 	struct se_device *dev = cmd->se_dev;
 	struct se_portal_group *tpg = cmd->se_lun->lun_sep->sep_tpg;
-	unsigned char *buf, *map_buf;
+	unsigned char *rbuf;
 	unsigned char *cdb = cmd->t_task_cdb;
+	unsigned char buf[SE_INQUIRY_BUF];
 	int p, ret;
 
-	map_buf = transport_kmap_data_sg(cmd);
-	/*
-	 * If SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC is not set, then we
-	 * know we actually allocated a full page.  Otherwise, if the
-	 * data buffer is too small, allocate a temporary buffer so we
-	 * don't have to worry about overruns in all our INQUIRY
-	 * emulation handling.
-	 */
-	if (cmd->data_length < SE_INQUIRY_BUF &&
-	    (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC)) {
-		buf = kzalloc(SE_INQUIRY_BUF, GFP_KERNEL);
-		if (!buf) {
-			transport_kunmap_data_sg(cmd);
-			cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-			return -ENOMEM;
-		}
-	} else {
-		buf = map_buf;
-	}
-
 	if (dev == tpg->tpg_virt_lun0.lun_se_dev)
 		buf[0] = 0x3f; /* Not connected */
 	else
@@ -655,11 +636,11 @@ static int spc_emulate_inquiry(struct se
 	ret = -EINVAL;
 
 out:
-	if (buf != map_buf) {
-		memcpy(map_buf, buf, cmd->data_length);
-		kfree(buf);
+	rbuf = transport_kmap_data_sg(cmd);
+	if (rbuf) {
+		memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
+		transport_kunmap_data_sg(cmd);
 	}
-	transport_kunmap_data_sg(cmd);
 
 	if (!ret)
 		target_complete_cmd(cmd, GOOD);


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/