From 91811a31b68d3765b3065f4bb6d7d6d84a7cfc9f Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Fri, 26 Apr 2024 08:44:08 +0200 Subject: [PATCH] i2c: smbus: fix NULL function pointer dereference Baruch reported an OOPS when using the designware controller as target only. Target-only modes break the assumption of one transfer function always being available. Fix this by always checking the pointer in __i2c_transfer. Reported-by: Baruch Siach Closes: https://lore.kernel.org/r/4269631780e5ba789cf1ae391eec1b959def7d99.1712761976.git.baruch@tkos.co.il Fixes: 4b1acc43331d ("i2c: core changes for slave support") [wsa: dropped the simplification in core-smbus to avoid theoretical regressions] Signed-off-by: Wolfram Sang Tested-by: Baruch Siach --- drivers/i2c/i2c-core-base.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index ff5c486a1dbb..db0d1ac82910 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -2200,13 +2200,18 @@ static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, * Returns negative errno, else the number of messages executed. * * Adapter lock must be held when calling this function. No debug logging - * takes place. adap->algo->master_xfer existence isn't checked. + * takes place. */ int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { unsigned long orig_jiffies; int ret, try; + if (!adap->algo->master_xfer) { + dev_dbg(&adap->dev, "I2C level transfers not supported\n"); + return -EOPNOTSUPP; + } + if (WARN_ON(!msgs || num < 1)) return -EINVAL; @@ -2273,11 +2278,6 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { int ret; - if (!adap->algo->master_xfer) { - dev_dbg(&adap->dev, "I2C level transfers not supported\n"); - return -EOPNOTSUPP; - } - /* REVISIT the fault reporting model here is weak: * * - When we get an error after receiving N bytes from a slave,