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authorWenwen Wang <wang6495@umn.edu>2018-05-05 08:02:21 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-11 16:31:32 +0200
commit328349288e77e9b5df4717af534c05670f47192f (patch)
parent091b5e3f593a8d34919b6226d58c00e18fb47305 (diff)
i2c: core: smbus: fix a potential missing-check bug
commit 8e03477cb709b73a2c1e1f4349ee3b7b33c50416 upstream. In i2c_smbus_xfer_emulated(), the function i2c_transfer() is invoked to transfer i2c messages. The number of actual transferred messages is returned and saved to 'status'. If 'status' is negative, that means an error occurred during the transfer process. In that case, the value of 'status' is an error code to indicate the reason of the transfer failure. In most cases, i2c_transfer() can transfer 'num' messages with no error. And so 'status' == 'num'. However, due to unexpected errors, it is probable that only partial messages are transferred by i2c_transfer(). As a result, 'status' != 'num'. This special case is not checked after the invocation of i2c_transfer() and can potentially lead to unexpected issues in the following execution since it is expected that 'status' == 'num'. This patch checks the return value of i2c_transfer() and returns an error code -EIO if the number of actual transferred messages 'status' is not equal to 'num'. Signed-off-by: Wenwen Wang <wang6495@umn.edu> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index b5aec33002c3..f3f683041e7f 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -466,6 +466,8 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
status = i2c_transfer(adapter, msg, num);
if (status < 0)
return status;
+ if (status != num)
+ return -EIO;
/* Check PEC if last message is a read */
if (i && (msg[num-1].flags & I2C_M_RD)) {