4.18-stable review patch. If anyone has any objections, please let me know.
------------------
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/target/target_core_user.c | 73 ++++++++++++++++++++------------------ 1 file changed, 40 insertions(+), 33 deletions(-)
--- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1745,9 +1745,11 @@ static int tcmu_configure_device(struct
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 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_par 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;