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| author | Dmitry Fomichev <dmitry.fomichev@wdc.com> | 2019-08-11 21:25:10 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-10 12:33:45 +0300 |
| commit | b8cd0b7b09ed932c7c16825ac9a853b2507e316c (patch) | |
| tree | f8a1ed1ea37fd33e9f807202848c82034177ef67 /drivers/target | |
| parent | 6c9a1e17d063d5466ff19614438baef4ac8f08ff (diff) | |
| download | linux-b8cd0b7b09ed932c7c16825ac9a853b2507e316c.tar.xz | |
scsi: target: tcmu: avoid use-after-free after command timeout
[ Upstream commit a86a75865ff4d8c05f355d1750a5250aec89ab15 ]
In tcmu_handle_completion() function, the variable called read_len is
always initialized with a value taken from se_cmd structure. If this
function is called to complete an expired (timed out) out command, the
session command pointed by se_cmd is likely to be already deallocated by
the target core at that moment. As the result, this access triggers a
use-after-free warning from KASAN.
This patch fixes the code not to touch se_cmd when completing timed out
TCMU commands. It also resets the pointer to se_cmd at the time when the
TCMU_CMD_BIT_EXPIRED flag is set because it is going to become invalid
after calling target_complete_cmd() later in the same function,
tcmu_check_expired_cmd().
Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com>
Acked-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/target_core_user.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index c46efa47d68a..7159e8363b83 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -1143,14 +1143,16 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * struct se_cmd *se_cmd = cmd->se_cmd; struct tcmu_dev *udev = cmd->tcmu_dev; bool read_len_valid = false; - uint32_t read_len = se_cmd->data_length; + uint32_t read_len; /* * cmd has been completed already from timeout, just reclaim * data area space and free cmd */ - if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) + if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { + WARN_ON_ONCE(se_cmd); goto out; + } list_del_init(&cmd->queue_entry); @@ -1163,6 +1165,7 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry * goto done; } + read_len = se_cmd->data_length; if (se_cmd->data_direction == DMA_FROM_DEVICE && (entry->hdr.uflags & TCMU_UFLAG_READ_LEN) && entry->rsp.read_len) { read_len_valid = true; @@ -1318,6 +1321,7 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data) */ scsi_status = SAM_STAT_CHECK_CONDITION; list_del_init(&cmd->queue_entry); + cmd->se_cmd = NULL; } else { list_del_init(&cmd->queue_entry); idr_remove(&udev->commands, id); @@ -2036,6 +2040,7 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level) idr_remove(&udev->commands, i); if (!test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) { + WARN_ON(!cmd->se_cmd); list_del_init(&cmd->queue_entry); if (err_level == 1) { /* |