From: Dmitry Torokhov <dtor@xxxxxxxxxxxx> This patch has been added to the 3.18 stable tree. If you have any objections, please let us know. =============== [ Upstream commit 3b654288b196ceaa156029d9457ccbded0489b98 ] Even though hid_hw_* checks that passed in data_len is less than HID_MAX_BUFFER_SIZE it is not enough, as i2c-hid does not necessarily allocate buffers of HID_MAX_BUFFER_SIZE but rather checks all device reports and select largest size. In-kernel users normally just send as much data as report needs, so there is no problem, but hidraw users can do whatever they please: BUG: KASAN: slab-out-of-bounds in memcpy+0x34/0x54 at addr ffffffc07135ea80 Write of size 4101 by task syz-executor/8747 CPU: 2 PID: 8747 Comm: syz-executor Tainted: G BU 3.18.0 #37 Hardware name: Google Tegra210 Smaug Rev 1,3+ (DT) Call trace: [<ffffffc00020ebcc>] dump_backtrace+0x0/0x258 arch/arm64/kernel/traps.c:83 [<ffffffc00020ee40>] show_stack+0x1c/0x2c arch/arm64/kernel/traps.c:172 [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffc001958114>] dump_stack+0x90/0x140 lib/dump_stack.c:50 [< inline >] print_error_description mm/kasan/report.c:97 [< inline >] kasan_report_error mm/kasan/report.c:278 [<ffffffc0004597dc>] kasan_report+0x268/0x530 mm/kasan/report.c:305 [<ffffffc0004592e8>] __asan_storeN+0x20/0x150 mm/kasan/kasan.c:718 [<ffffffc0004594e0>] memcpy+0x30/0x54 mm/kasan/kasan.c:299 [<ffffffc001306354>] __i2c_hid_command+0x2b0/0x7b4 drivers/hid/i2c-hid/i2c-hid.c:178 [< inline >] i2c_hid_set_or_send_report drivers/hid/i2c-hid/i2c-hid.c:321 [<ffffffc0013079a0>] i2c_hid_output_raw_report.isra.2+0x3d4/0x4b8 drivers/hid/i2c-hid/i2c-hid.c:589 [<ffffffc001307ad8>] i2c_hid_output_report+0x54/0x68 drivers/hid/i2c-hid/i2c-hid.c:602 [< inline >] hid_hw_output_report include/linux/hid.h:1039 [<ffffffc0012cc7a0>] hidraw_send_report+0x400/0x414 drivers/hid/hidraw.c:154 [<ffffffc0012cc7f4>] hidraw_write+0x40/0x64 drivers/hid/hidraw.c:177 [<ffffffc0004681dc>] vfs_write+0x1d4/0x3cc fs/read_write.c:534 [< inline >] SYSC_pwrite64 fs/read_write.c:627 [<ffffffc000468984>] SyS_pwrite64+0xec/0x144 fs/read_write.c:614 Object at ffffffc07135ea80, in cache kmalloc-512 Object allocated with size 268 bytes. Let's check data length against the buffer size before attempting to copy data over. Cc: stable@xxxxxxxxxxxxxxx Reported-by: Alexander Potapenko <glider@xxxxxxxxxx> Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxxxx> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> --- drivers/hid/i2c-hid/i2c-hid.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c index 6d7c9c5..fdcce35 100644 --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -277,17 +277,21 @@ static int i2c_hid_set_or_send_report(struct i2c_client *client, u8 reportType, u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister); u16 outputRegister = le16_to_cpu(ihid->hdesc.wOutputRegister); u16 maxOutputLength = le16_to_cpu(ihid->hdesc.wMaxOutputLength); + u16 size; + int args_len; + int index = 0; + + i2c_hid_dbg(ihid, "%s\n", __func__); + + if (data_len > ihid->bufsize) + return -EINVAL; - /* hid_hw_* already checked that data_len < HID_MAX_BUFFER_SIZE */ - u16 size = 2 /* size */ + + size = 2 /* size */ + (reportID ? 1 : 0) /* reportID */ + data_len /* buf */; - int args_len = (reportID >= 0x0F ? 1 : 0) /* optional third byte */ + + args_len = (reportID >= 0x0F ? 1 : 0) /* optional third byte */ + 2 /* dataRegister */ + size /* args */; - int index = 0; - - i2c_hid_dbg(ihid, "%s\n", __func__); if (!use_data && maxOutputLength == 0) return -ENOSYS; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html