6.6-stable review patch. If anyone has any objections, please let me know.
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From: Julien Stephan jstephan@baylibre.com
[ Upstream commit c4ec8dedca961db056ec85cb7ca8c9f7e2e92252 ]
Some callbacks from iio_info structure are accessed without any check, so if a driver doesn't implement them trying to access the corresponding sysfs entries produce a kernel oops such as:
[ 2203.527791] Unable to handle kernel NULL pointer dereference at virtual address 00000000 when execute [...] [ 2203.783416] Call trace: [ 2203.783429] iio_read_channel_info_avail from dev_attr_show+0x18/0x48 [ 2203.789807] dev_attr_show from sysfs_kf_seq_show+0x90/0x120 [ 2203.794181] sysfs_kf_seq_show from seq_read_iter+0xd0/0x4e4 [ 2203.798555] seq_read_iter from vfs_read+0x238/0x2a0 [ 2203.802236] vfs_read from ksys_read+0xa4/0xd4 [ 2203.805385] ksys_read from ret_fast_syscall+0x0/0x54 [ 2203.809135] Exception stack(0xe0badfa8 to 0xe0badff0) [ 2203.812880] dfa0: 00000003 b6f10f80 00000003 b6eab000 00020000 00000000 [ 2203.819746] dfc0: 00000003 b6f10f80 7ff00000 00000003 00000003 00000000 00020000 00000000 [ 2203.826619] dfe0: b6e1bc88 bed80958 b6e1bc94 b6e1bcb0 [ 2203.830363] Code: bad PC value [ 2203.832695] ---[ end trace 0000000000000000 ]---
Reviewed-by: Nuno Sa nuno.sa@analog.com Signed-off-by: Julien Stephan jstephan@baylibre.com Link: https://lore.kernel.org/r/20240530-iio-core-fix-segfault-v3-1-8b7cd2a03773@b... Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iio/industrialio-core.c | 7 ++++++- drivers/iio/industrialio-event.c | 9 +++++++++ drivers/iio/inkern.c | 32 ++++++++++++++++++++++---------- 3 files changed, 37 insertions(+), 11 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 5e1a85ca1211..121bde49ccb7 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -752,9 +752,11 @@ static ssize_t iio_read_channel_info(struct device *dev, INDIO_MAX_RAW_ELEMENTS, vals, &val_len, this_attr->address); - else + else if (indio_dev->info->read_raw) ret = indio_dev->info->read_raw(indio_dev, this_attr->c, &vals[0], &vals[1], this_attr->address); + else + return -EINVAL;
if (ret < 0) return ret; @@ -836,6 +838,9 @@ static ssize_t iio_read_channel_info_avail(struct device *dev, int length; int type;
+ if (!indio_dev->info->read_avail) + return -EINVAL; + ret = indio_dev->info->read_avail(indio_dev, this_attr->c, &vals, &type, &length, this_attr->address); diff --git a/drivers/iio/industrialio-event.c b/drivers/iio/industrialio-event.c index 19f7a91157ee..f67e4afa5f94 100644 --- a/drivers/iio/industrialio-event.c +++ b/drivers/iio/industrialio-event.c @@ -285,6 +285,9 @@ static ssize_t iio_ev_state_store(struct device *dev, if (ret < 0) return ret;
+ if (!indio_dev->info->write_event_config) + return -EINVAL; + ret = indio_dev->info->write_event_config(indio_dev, this_attr->c, iio_ev_attr_type(this_attr), iio_ev_attr_dir(this_attr), val); @@ -300,6 +303,9 @@ static ssize_t iio_ev_state_show(struct device *dev, struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); int val;
+ if (!indio_dev->info->read_event_config) + return -EINVAL; + val = indio_dev->info->read_event_config(indio_dev, this_attr->c, iio_ev_attr_type(this_attr), iio_ev_attr_dir(this_attr)); @@ -318,6 +324,9 @@ static ssize_t iio_ev_value_show(struct device *dev, int val, val2, val_arr[2]; int ret;
+ if (!indio_dev->info->read_event_value) + return -EINVAL; + ret = indio_dev->info->read_event_value(indio_dev, this_attr->c, iio_ev_attr_type(this_attr), iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index 7a1f6713318a..b85556538475 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -562,6 +562,7 @@ EXPORT_SYMBOL_GPL(devm_iio_channel_get_all); static int iio_channel_read(struct iio_channel *chan, int *val, int *val2, enum iio_chan_info_enum info) { + const struct iio_info *iio_info = chan->indio_dev->info; int unused; int vals[INDIO_MAX_RAW_ELEMENTS]; int ret; @@ -573,15 +574,18 @@ static int iio_channel_read(struct iio_channel *chan, int *val, int *val2, if (!iio_channel_has_info(chan->channel, info)) return -EINVAL;
- if (chan->indio_dev->info->read_raw_multi) { - ret = chan->indio_dev->info->read_raw_multi(chan->indio_dev, - chan->channel, INDIO_MAX_RAW_ELEMENTS, - vals, &val_len, info); + if (iio_info->read_raw_multi) { + ret = iio_info->read_raw_multi(chan->indio_dev, + chan->channel, + INDIO_MAX_RAW_ELEMENTS, + vals, &val_len, info); *val = vals[0]; *val2 = vals[1]; + } else if (iio_info->read_raw) { + ret = iio_info->read_raw(chan->indio_dev, + chan->channel, val, val2, info); } else { - ret = chan->indio_dev->info->read_raw(chan->indio_dev, - chan->channel, val, val2, info); + return -EINVAL; }
return ret; @@ -801,11 +805,15 @@ static int iio_channel_read_avail(struct iio_channel *chan, const int **vals, int *type, int *length, enum iio_chan_info_enum info) { + const struct iio_info *iio_info = chan->indio_dev->info; + if (!iio_channel_has_available(chan->channel, info)) return -EINVAL;
- return chan->indio_dev->info->read_avail(chan->indio_dev, chan->channel, - vals, type, length, info); + if (iio_info->read_avail) + return iio_info->read_avail(chan->indio_dev, chan->channel, + vals, type, length, info); + return -EINVAL; }
int iio_read_avail_channel_attribute(struct iio_channel *chan, @@ -995,8 +1003,12 @@ EXPORT_SYMBOL_GPL(iio_get_channel_type); static int iio_channel_write(struct iio_channel *chan, int val, int val2, enum iio_chan_info_enum info) { - return chan->indio_dev->info->write_raw(chan->indio_dev, - chan->channel, val, val2, info); + const struct iio_info *iio_info = chan->indio_dev->info; + + if (iio_info->write_raw) + return iio_info->write_raw(chan->indio_dev, + chan->channel, val, val2, info); + return -EINVAL; }
int iio_write_channel_attribute(struct iio_channel *chan, int val, int val2,