On some systems the firmware may not describe all the ports
connected to a component (e.g, for security reasons). This
could be especially problematic for "funnels" where we could
end up in modifying memory beyond the allocated space for
refcounts.
e.g, for a funnel with input ports listed 0, 3, 5, nr_inport = 3.
However the we could access refcnts[5] while checking for
references, like :
[ 526.110401] ==================================================================
[ 526.117988] BUG: KASAN: slab-out-of-bounds in funnel_enable+0x54/0x1b0
[ 526.124706] Read of size 4 at addr ffffff8135f9549c by task bash/1114
[ 526.131324]
[ 526.132886] CPU: 3 PID: 1114 Comm: bash Tainted: G S 5.4.25 #232
[ 526.140397] Hardware name: Qualcomm Technologies, Inc. SC7180 IDP (DT)
[ 526.147113] Call trace:
[ 526.149653] dump_backtrace+0x0/0x188
[ 526.153431] show_stack+0x20/0x2c
[ 526.156852] dump_stack+0xdc/0x144
[ 526.160370] print_address_description+0x3c/0x494
[ 526.165211] __kasan_report+0x144/0x168
[ 526.169170] kasan_report+0x10/0x18
[ 526.172769] check_memory_region+0x1a4/0x1b4
[ 526.177164] __kasan_check_read+0x18/0x24
[ 526.181292] funnel_enable+0x54/0x1b0
[ 526.185072] coresight_enable_path+0x104/0x198
[ 526.189649] coresight_enable+0x118/0x26c
...
[ 526.237782] Allocated by task 280:
[ 526.241298] __kasan_kmalloc+0xf0/0x1ac
[ 526.245249] kasan_kmalloc+0xc/0x14
[ 526.248849] __kmalloc+0x28c/0x3b4
[ 526.252361] coresight_register+0x88/0x250
[ 526.256587] funnel_probe+0x15c/0x228
[ 526.260365] dynamic_funnel_probe+0x20/0x2c
[ 526.264679] amba_probe+0xbc/0x158
[ 526.268193] really_probe+0x144/0x408
[ 526.271970] driver_probe_device+0x70/0x140
...
[ 526.316810]
[ 526.318364] Freed by task 0:
[ 526.321344] (stack is not available)
[ 526.325024]
[ 526.326580] The buggy address belongs to the object at ffffff8135f95480
[ 526.326580] which belongs to the cache kmalloc-128 of size 128
[ 526.339439] The buggy address is located 28 bytes inside of
[ 526.339439] 128-byte region [ffffff8135f95480, ffffff8135f95500)
[ 526.351399] The buggy address belongs to the page:
[ 526.356342] page:ffffffff04b7e500 refcount:1 mapcount:0 mapping:ffffff814b00c380 index:0x0 compound_mapcount: 0
[ 526.366711] flags: 0x4000000000010200(slab|head)
[ 526.371475] raw: 4000000000010200 ffffffff05034008 ffffffff0501eb08 ffffff814b00c380
[ 526.379435] raw: 0000000000000000 0000000000190019 00000001ffffffff 0000000000000000
[ 526.387393] page dumped because: kasan: bad access detected
[ 526.393128]
[ 526.394681] Memory state around the buggy address:
[ 526.399619] ffffff8135f95380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.407046] ffffff8135f95400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.414473] >ffffff8135f95480: 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.421900] ^
[ 526.426029] ffffff8135f95500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.433456] ffffff8135f95580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 526.440883] ==================================================================
To keep the code simple, we now track the maximum number of
possible input/output connections to/from this component
@ nr_inport and nr_outport in platform_data, respectively.
Thus the output connections could be sparse and code is
adjusted to skip the unspecified connections.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Reported-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-13-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>