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| author | Jiangshan Yi <yijiangshan@kylinos.cn> | 2026-07-28 21:14:41 +0800 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.com> | 2026-08-03 19:20:55 +0200 |
| commit | db2333f88729c8aae062cb171ed058725ff5c901 (patch) | |
| tree | 90b925c29883e6d60f066fe20c833ca0198fb28c | |
| parent | dca151633c0fde90935311c60e7cfc064aa56134 (diff) | |
| download | linux-db2333f88729c8aae062cb171ed058725ff5c901.tar.gz linux-db2333f88729c8aae062cb171ed058725ff5c901.zip | |
HID: mcp2221: clear rxbuf after I2C/SMBus transfer completes
mcp_i2c_smbus_read() stores the caller-supplied buffer pointer in
mcp->rxbuf for the duration of a transfer but never clears it when the
transfer finishes or times out. Once the caller frees or reuses the
buffer, mcp->rxbuf becomes a dangling pointer. A delayed or spurious
MCP2221_I2C_GET_DATA report can then drive mcp2221_raw_event() to
memcpy device data into the freed memory, causing a write
use-after-free.
Route all return paths through a single exit point that clears
mcp->rxbuf and mcp->rxbuf_size, so that the existing !mcp->rxbuf guard
in the raw_event handler can reject any report arriving after the
transfer has ended.
Fixes: 67a95c21463d ("HID: mcp2221: add usb to i2c-smbus host bridge")
Cc: stable@vger.kernel.org
Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
| -rw-r--r-- | drivers/hid/hid-mcp2221.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c index 5c7fc56c7c67..9e03d1f733ff 100644 --- a/drivers/hid/hid-mcp2221.c +++ b/drivers/hid/hid-mcp2221.c @@ -343,7 +343,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, ret = mcp_send_data_req_status(mcp, mcp->txbuf, 4); if (ret) - return ret; + goto out; mcp->rxbuf_idx = 0; @@ -365,7 +365,7 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, } else { usleep_range(980, 1000); mcp_cancel_last_cmd(mcp); - return ret; + goto out; } } else { retries = 0; @@ -375,6 +375,10 @@ static int mcp_i2c_smbus_read(struct mcp2221 *mcp, usleep_range(980, 1000); ret = mcp_chk_last_cmd_status_free_bus(mcp); +out: + mcp->rxbuf = NULL; + mcp->rxbuf_size = 0; + return ret; } |