There is a window between freeing md->ima.active_table.hash and setting md->ima.active_table.hash to NULL in dm_ima_measure_on_device_resume(). If dm_ima_measure_on_device_remove() accesses md->ima.active_table.hash concurrently during this window, it could lead to a double free or UAF, as shown below:
BUG: KASAN: slab-use-after-free in dm_ima_measure_on_device_remove... Read of size 71 at addr ffff88817bb9e220 by task dmsetup/2303 CPU: 2 UID: 0 PID: 2303 Comm: dmsetup Not tainted 6.16.0-rc6-dirty... Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3... Call Trace: <TASK> dump_stack_lvl+0x5b/0x80 print_address_description.constprop.0+0x88/0x310 print_report+0x12f/0x21d kasan_report+0xcc/0x190 kasan_check_range+0x104/0x1b0 __asan_memcpy+0x23/0x60 dm_ima_measure_on_device_remove+0x3fc/0x6c0 dev_remove+0x123/0x1e0 ctl_ioctl+0x2a2/0x480 dm_ctl_ioctl+0xe/0x20 __x64_sys_ioctl+0xc7/0x110 do_syscall_64+0x72/0x390 entry_SYSCALL_64_after_hwframe+0x76/0x7e To reproduce this issue, add a delay between freeing md->ima.active_table.hash and setting it to NULL, using the following steps: dmsetup create mydevice --table "0 2097152 linear /dev/sda 0" dmsetup suspend mydevice dmsetup reload mydevice --table "0 2097152 linear /dev/sdb 0" dmsetup resume mydevice & dmsetup remove mydevice Introduce ima_lock to prevent concurrent calls to dm_ima_measure_* functions to fix it. Fixes: 91ccbbac1747 ("dm ima: measure data on table load") Signed-off-by: Li Lingfeng <lilingfe...@huawei.com> --- drivers/md/dm-core.h | 1 + drivers/md/dm-ima.c | 38 +++++++++++++++++++++++++++++++++----- drivers/md/dm-ima.h | 4 ++++ drivers/md/dm.c | 3 ++- 4 files changed, 40 insertions(+), 6 deletions(-) diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index c889332e533b..24f321b2c2c4 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -145,6 +145,7 @@ struct mapped_device { #endif #ifdef CONFIG_IMA + struct mutex ima_lock; struct dm_ima_measurements ima; #endif }; diff --git a/drivers/md/dm-ima.c b/drivers/md/dm-ima.c index b90f34259fbb..0fefad6fbb9f 100644 --- a/drivers/md/dm-ima.c +++ b/drivers/md/dm-ima.c @@ -164,7 +164,7 @@ static int dm_ima_alloc_and_copy_capacity_str(struct mapped_device *md, char **c } /* - * Initialize/reset the dm ima related data structure variables. + * Reset the dm ima related data structure variables. */ void dm_ima_reset_data(struct mapped_device *md) { @@ -172,6 +172,23 @@ void dm_ima_reset_data(struct mapped_device *md) md->ima.dm_version_str_len = strlen(DM_IMA_VERSION_STR); } +/* + * Initialize the dm ima. + */ +void dm_ima_init(struct mapped_device *md) +{ + dm_ima_reset_data(md); + mutex_init(&md->ima_lock); +} + +/* + * Destroy the dm ima related data structure. + */ +void dm_ima_destroy(struct mapped_device *md) +{ + mutex_destroy(&md->ima_lock); +} + /* * Build up the IMA data for each target, and finally measure. */ @@ -195,9 +212,10 @@ void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_fl const size_t hash_alg_prefix_len = strlen(DM_IMA_TABLE_HASH_ALG) + 1; char table_load_event_name[] = "dm_table_load"; + mutex_lock(&table->md->ima_lock); ima_buf = dm_ima_alloc(DM_IMA_MEASUREMENT_BUF_LEN, GFP_KERNEL, noio); if (!ima_buf) - return; + goto error; target_metadata_buf = dm_ima_alloc(DM_IMA_TARGET_METADATA_BUF_LEN, GFP_KERNEL, noio); if (!target_metadata_buf) @@ -361,6 +379,7 @@ void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_fl kfree(ima_buf); kfree(target_metadata_buf); kfree(target_data_buf); + mutex_unlock(&table->md->ima_lock); } /* @@ -376,9 +395,10 @@ void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap) bool nodata = true; int r; + mutex_lock(&md->ima_lock); device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, GFP_KERNEL, noio); if (!device_table_data) - return; + goto error; r = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio); if (r) @@ -466,6 +486,7 @@ void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap) error: kfree(capacity_str); kfree(device_table_data); + mutex_unlock(&md->ima_lock); } /* @@ -490,6 +511,7 @@ void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all) bool nodata = true; int r; + mutex_lock(&md->ima_lock); device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN*2, GFP_KERNEL, noio); if (!device_table_data) goto exit; @@ -597,6 +619,7 @@ void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all) kfree(dev_name); kfree(dev_uuid); + mutex_unlock(&md->ima_lock); } /* @@ -612,9 +635,10 @@ void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map) bool nodata = true; int r; + mutex_lock(&md->ima_lock); device_table_data = dm_ima_alloc(DM_IMA_DEVICE_BUF_LEN, GFP_KERNEL, noio); if (!device_table_data) - return; + goto error; r = dm_ima_alloc_and_copy_capacity_str(md, &capacity_str, noio); if (r) @@ -696,6 +720,8 @@ void dm_ima_measure_on_table_clear(struct mapped_device *md, bool new_map) kfree(capacity_str); error1: kfree(device_table_data); +error: + mutex_unlock(&md->ima_lock); } /* @@ -708,9 +734,10 @@ void dm_ima_measure_on_device_rename(struct mapped_device *md) bool noio = true; int r; + mutex_lock(&md->ima_lock); if (dm_ima_alloc_and_copy_device_data(md, &new_device_data, md->ima.active_table.num_targets, noio)) - return; + goto error; if (dm_ima_alloc_and_copy_name_uuid(md, &new_dev_name, &new_dev_uuid, noio)) goto error; @@ -745,4 +772,5 @@ void dm_ima_measure_on_device_rename(struct mapped_device *md) kfree(old_device_data); kfree(new_dev_name); kfree(new_dev_uuid); + mutex_unlock(&md->ima_lock); } diff --git a/drivers/md/dm-ima.h b/drivers/md/dm-ima.h index 568870a1a145..36bbcf1b25a0 100644 --- a/drivers/md/dm-ima.h +++ b/drivers/md/dm-ima.h @@ -57,6 +57,8 @@ struct dm_ima_measurements { }; void dm_ima_reset_data(struct mapped_device *md); +void dm_ima_init(struct mapped_device *md); +void dm_ima_destroy(struct mapped_device *md); void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags); void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap); void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all); @@ -66,6 +68,8 @@ void dm_ima_measure_on_device_rename(struct mapped_device *md); #else static inline void dm_ima_reset_data(struct mapped_device *md) {} +static inline void dm_ima_init(struct mapped_device *md) {} +static inline void dm_ima_destroy(struct mapped_device *md) {} static inline void dm_ima_measure_on_table_load(struct dm_table *table, unsigned int status_flags) {} static inline void dm_ima_measure_on_device_resume(struct mapped_device *md, bool swap) {} static inline void dm_ima_measure_on_device_remove(struct mapped_device *md, bool remove_all) {} diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 1726f0f828cc..b7eab324804c 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2371,6 +2371,7 @@ static void free_dev(struct mapped_device *md) unlock_fs(md); cleanup_mapped_device(md); + dm_ima_destroy(md); WARN_ON_ONCE(!list_empty(&md->table_devices)); dm_stats_cleanup(&md->stats); @@ -2506,7 +2507,7 @@ int dm_create(int minor, struct mapped_device **result) if (!md) return -ENXIO; - dm_ima_reset_data(md); + dm_ima_init(md); *result = md; return 0; -- 2.46.1