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Subject[PATCH AUTOSEL 4.18 059/131] scsi: tcmu: do not set max_blocks if data_bitmap has been setup
Date
From: Mike Christie <mchristi@redhat.com>

[ Upstream commit c97840c84f5a4362a596a2751e9245a979377a16 ]

This patch prevents a bug where data_bitmap is allocated in
tcmu_configure_device, userspace changes the max_blocks setting, the device
is mapped to a LUN, then we try to access the data_bitmap based on the new
max_blocks limit which may now be out of range.

To prevent this, we just check if data_bitmap has been setup. If it has
then we fail the max_blocks update operation.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/target/target_core_user.c | 73 +++++++++++++++++--------------
1 file changed, 40 insertions(+), 33 deletions(-)

diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index d8dc3d22051f..b8dc5efc606b 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -1745,9 +1745,11 @@ static int tcmu_configure_device(struct se_device *dev)

info = &udev->uio_info;

+ mutex_lock(&udev->cmdr_lock);
udev->data_bitmap = kcalloc(BITS_TO_LONGS(udev->max_blocks),
sizeof(unsigned long),
GFP_KERNEL);
+ mutex_unlock(&udev->cmdr_lock);
if (!udev->data_bitmap) {
ret = -ENOMEM;
goto err_bitmap_alloc;
@@ -1957,7 +1959,7 @@ static match_table_t tokens = {
{Opt_hw_block_size, "hw_block_size=%u"},
{Opt_hw_max_sectors, "hw_max_sectors=%u"},
{Opt_nl_reply_supported, "nl_reply_supported=%d"},
- {Opt_max_data_area_mb, "max_data_area_mb=%u"},
+ {Opt_max_data_area_mb, "max_data_area_mb=%d"},
{Opt_err, NULL}
};

@@ -1985,13 +1987,48 @@ static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
return 0;
}

+static int tcmu_set_max_blocks_param(struct tcmu_dev *udev, substring_t *arg)
+{
+ int val, ret;
+
+ ret = match_int(arg, &val);
+ if (ret < 0) {
+ pr_err("match_int() failed for max_data_area_mb=. Error %d.\n",
+ ret);
+ return ret;
+ }
+
+ if (val <= 0) {
+ pr_err("Invalid max_data_area %d.\n", val);
+ return -EINVAL;
+ }
+
+ mutex_lock(&udev->cmdr_lock);
+ if (udev->data_bitmap) {
+ pr_err("Cannot set max_data_area_mb after it has been enabled.\n");
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ udev->max_blocks = TCMU_MBS_TO_BLOCKS(val);
+ if (udev->max_blocks > tcmu_global_max_blocks) {
+ pr_err("%d is too large. Adjusting max_data_area_mb to global limit of %u\n",
+ val, TCMU_BLOCKS_TO_MBS(tcmu_global_max_blocks));
+ udev->max_blocks = tcmu_global_max_blocks;
+ }
+
+unlock:
+ mutex_unlock(&udev->cmdr_lock);
+ return ret;
+}
+
static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
const char *page, ssize_t count)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
char *orig, *ptr, *opts, *arg_p;
substring_t args[MAX_OPT_ARGS];
- int ret = 0, token, tmpval;
+ int ret = 0, token;

opts = kstrdup(page, GFP_KERNEL);
if (!opts)
@@ -2044,37 +2081,7 @@ static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
pr_err("kstrtoint() failed for nl_reply_supported=\n");
break;
case Opt_max_data_area_mb:
- if (dev->export_count) {
- pr_err("Unable to set max_data_area_mb while exports exist\n");
- ret = -EINVAL;
- break;
- }
-
- arg_p = match_strdup(&args[0]);
- if (!arg_p) {
- ret = -ENOMEM;
- break;
- }
- ret = kstrtoint(arg_p, 0, &tmpval);
- kfree(arg_p);
- if (ret < 0) {
- pr_err("kstrtoint() failed for max_data_area_mb=\n");
- break;
- }
-
- if (tmpval <= 0) {
- pr_err("Invalid max_data_area %d\n", tmpval);
- ret = -EINVAL;
- break;
- }
-
- udev->max_blocks = TCMU_MBS_TO_BLOCKS(tmpval);
- if (udev->max_blocks > tcmu_global_max_blocks) {
- pr_err("%d is too large. Adjusting max_data_area_mb to global limit of %u\n",
- tmpval,
- TCMU_BLOCKS_TO_MBS(tcmu_global_max_blocks));
- udev->max_blocks = tcmu_global_max_blocks;
- }
+ ret = tcmu_set_max_blocks_param(udev, &args[0]);
break;
default:
break;
--
2.17.1
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