[PATCH AUTOSEL 5.15 19/68] scsi: scsi_debug: Fix type in min_t to avoid stack OOB

Sasha Levin
2021-11-30T14:49:04Z

From: George Kennedy <george.kennedy@oracle.com>

[ Upstream commit 36e07d7ede88a1f1ef8f0f209af5b7612324ac2c ]

Change min_t() to use type "u32" instead of type "int" to avoid stack out
of bounds. With min_t() type "int" the values get sign extended and the
larger value gets used causing stack out of bounds.

BUG: KASAN: stack-out-of-bounds in memcpy include/linux/fortify-string.h:191 [inline]
BUG: KASAN: stack-out-of-bounds in sg_copy_buffer+0x1de/0x240 lib/scatterlist.c:976
Read of size 127 at addr ffff888072607128 by task syz-executor.7/18707

CPU: 1 PID: 18707 Comm: syz-executor.7 Not tainted 5.15.0-syzk #1
Hardware name: Red Hat KVM, BIOS 1.13.0-2
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x89/0xb5 lib/dump_stack.c:106
print_address_description.constprop.9+0x28/0x160 mm/kasan/report.c:256
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold.14+0x7d/0x117 mm/kasan/report.c:459
check_region_inline mm/kasan/generic.c:183 [inline]
kasan_check_range+0x1a3/0x210 mm/kasan/generic.c:189
memcpy+0x23/0x60 mm/kasan/shadow.c:65
memcpy include/linux/fortify-string.h:191 [inline]
sg_copy_buffer+0x1de/0x240 lib/scatterlist.c:976
sg_copy_from_buffer+0x33/0x40 lib/scatterlist.c:1000
fill_from_dev_buffer.part.34+0x82/0x130 drivers/scsi/scsi_debug.c:1162
fill_from_dev_buffer drivers/scsi/scsi_debug.c:1888 [inline]
resp_readcap16+0x365/0x3b0 drivers/scsi/scsi_debug.c:1887
schedule_resp+0x4d8/0x1a70 drivers/scsi/scsi_debug.c:5478
scsi_debug_queuecommand+0x8c9/0x1ec0 drivers/scsi/scsi_debug.c:7533
scsi_dispatch_cmd drivers/scsi/scsi_lib.c:1520 [inline]
scsi_queue_rq+0x16b0/0x2d40 drivers/scsi/scsi_lib.c:1699
blk_mq_dispatch_rq_list+0xb9b/0x2700 block/blk-mq.c:1639
__blk_mq_sched_dispatch_requests+0x28f/0x590 block/blk-mq-sched.c:325
blk_mq_sched_dispatch_requests+0x105/0x190 block/blk-mq-sched.c:358
__blk_mq_run_hw_queue+0xe5/0x150 block/blk-mq.c:1761
__blk_mq_delay_run_hw_queue+0x4f8/0x5c0 block/blk-mq.c:1838
blk_mq_run_hw_queue+0x18d/0x350 block/blk-mq.c:1891
blk_mq_sched_insert_request+0x3db/0x4e0 block/blk-mq-sched.c:474
blk_execute_rq_nowait+0x16b/0x1c0 block/blk-exec.c:62
sg_common_write.isra.18+0xeb3/0x2000 drivers/scsi/sg.c:836
sg_new_write.isra.19+0x570/0x8c0 drivers/scsi/sg.c:774
sg_ioctl_common+0x14d6/0x2710 drivers/scsi/sg.c:939
sg_ioctl+0xa2/0x180 drivers/scsi/sg.c:1165
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x19d/0x220 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Link: https://lore.kernel.org/r/1636484247-21254-1-git-send-email-george.kennedy@oracle.com
Reported-by: syzkaller <syzkaller@googlegroups.com>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/scsi_debug.c | 34 +++++++++++++++++++---------------
1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index ead65cdfb522e..871b5e1e5b8f1 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -1189,7 +1189,7 @@ static int p_fill_from_dev_buffer(struct scsi_cmnd *scp, const void *arr,
__func__, off_dst, scsi_bufflen(scp), act_len,
scsi_get_resid(scp));
n = scsi_bufflen(scp) - (off_dst + act_len);
- scsi_set_resid(scp, min_t(int, scsi_get_resid(scp), n));
+ scsi_set_resid(scp, min_t(u32, scsi_get_resid(scp), n));
return 0;
}

@@ -1562,7 +1562,8 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
unsigned char pq_pdt;
unsigned char *arr;
unsigned char *cmd = scp->cmnd;
- int alloc_len, n, ret;
+ u32 alloc_len, n;
+ int ret;
bool have_wlun, is_disk, is_zbc, is_disk_zbc;

alloc_len = get_unaligned_be16(cmd + 3);
@@ -1585,7 +1586,8 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
kfree(arr);
return check_condition_result;
} else if (0x1 & cmd[1]) { /* EVPD bit set */
- int lu_id_num, port_group_id, target_dev_id, len;
+ int lu_id_num, port_group_id, target_dev_id;
+ u32 len;
char lu_id_str[6];
int host_no = devip->sdbg_host->shost->host_no;

@@ -1676,9 +1678,9 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
kfree(arr);
return check_condition_result;
}
- len = min(get_unaligned_be16(arr + 2) + 4, alloc_len);
+ len = min_t(u32, get_unaligned_be16(arr + 2) + 4, alloc_len);
ret = fill_from_dev_buffer(scp, arr,
- min(len, SDEBUG_MAX_INQ_ARR_SZ));
+ min_t(u32, len, SDEBUG_MAX_INQ_ARR_SZ));
kfree(arr);
return ret;
}
@@ -1714,7 +1716,7 @@ static int resp_inquiry(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
}
put_unaligned_be16(0x2100, arr + n); /* SPL-4 no version claimed */
ret = fill_from_dev_buffer(scp, arr,
- min_t(int, alloc_len, SDEBUG_LONG_INQ_SZ));
+ min_t(u32, alloc_len, SDEBUG_LONG_INQ_SZ));
kfree(arr);
return ret;
}
@@ -1729,8 +1731,8 @@ static int resp_requests(struct scsi_cmnd *scp,
unsigned char *cmd = scp->cmnd;
unsigned char arr[SCSI_SENSE_BUFFERSIZE]; /* assume >= 18 bytes */
bool dsense = !!(cmd[1] & 1);
- int alloc_len = cmd[4];
- int len = 18;
+ u32 alloc_len = cmd[4];
+ u32 len = 18;
int stopped_state = atomic_read(&devip->stopped);

memset(arr, 0, sizeof(arr));
@@ -1774,7 +1776,7 @@ static int resp_requests(struct scsi_cmnd *scp,
arr[7] = 0xa;
}
}
- return fill_from_dev_buffer(scp, arr, min_t(int, len, alloc_len));
+ return fill_from_dev_buffer(scp, arr, min_t(u32, len, alloc_len));
}

static int resp_start_stop(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
@@ -2312,7 +2314,8 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
{
int pcontrol, pcode, subpcode, bd_len;
unsigned char dev_spec;
- int alloc_len, offset, len, target_dev_id;
+ u32 alloc_len, offset, len;
+ int target_dev_id;
int target = scp->device->id;
unsigned char *ap;
unsigned char arr[SDEBUG_MAX_MSENSE_SZ];
@@ -2468,7 +2471,7 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
arr[0] = offset - 1;
else
put_unaligned_be16((offset - 2), arr + 0);
- return fill_from_dev_buffer(scp, arr, min_t(int, alloc_len, offset));
+ return fill_from_dev_buffer(scp, arr, min_t(u32, alloc_len, offset));
}

#define SDEBUG_MAX_MSELECT_SZ 512
@@ -2583,7 +2586,8 @@ static int resp_ie_l_pg(unsigned char *arr)
static int resp_log_sense(struct scsi_cmnd *scp,
struct sdebug_dev_info *devip)
{
- int ppc, sp, pcode, subpcode, alloc_len, len, n;
+ int ppc, sp, pcode, subpcode;
+ u32 alloc_len, len, n;
unsigned char arr[SDEBUG_MAX_LSENSE_SZ];
unsigned char *cmd = scp->cmnd;

@@ -2653,9 +2657,9 @@ static int resp_log_sense(struct scsi_cmnd *scp,
mk_sense_invalid_fld(scp, SDEB_IN_CDB, 3, -1);
return check_condition_result;
}
- len = min_t(int, get_unaligned_be16(arr + 2) + 4, alloc_len);
+ len = min_t(u32, get_unaligned_be16(arr + 2) + 4, alloc_len);
return fill_from_dev_buffer(scp, arr,
- min_t(int, len, SDEBUG_MAX_INQ_ARR_SZ));
+ min_t(u32, len, SDEBUG_MAX_INQ_ARR_SZ));
}

static inline bool sdebug_dev_is_zoned(struct sdebug_dev_info *devip)
@@ -4426,7 +4430,7 @@ static int resp_report_zones(struct scsi_cmnd *scp,
put_unaligned_be64(sdebug_capacity - 1, arr + 8);

rep_len = (unsigned long)desc - (unsigned long)arr;
- ret = fill_from_dev_buffer(scp, arr, min_t(int, alloc_len, rep_len));
+ ret = fill_from_dev_buffer(scp, arr, min_t(u32, alloc_len, rep_len));

fini:
read_unlock(macc_lckp);
--
2.33.0