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authorJeremy Compostella <jeremy.compostella@intel.com>2017-11-15 12:31:44 -0700
committerWolfram Sang <wsa@the-dreams.de>2018-01-17 15:35:21 +0100
commit89c6efa61f5709327ecfa24bff18e57a4e80c7fa (patch)
tree7b347b13836cd294f38a1b0cd5e0d02bc8e33a9b /drivers/i2c
parente0638fa400eaccf9fa8060f67140264c4e276552 (diff)
i2c: core-smbus: prevent stack corruption on read I2C_BLOCK_DATA
On a I2C_SMBUS_I2C_BLOCK_DATA read request, if data->block[0] is greater than I2C_SMBUS_BLOCK_MAX + 1, the underlying I2C driver writes data out of the msgbuf1 array boundary. It is possible from a user application to run into that issue by calling the I2C_SMBUS ioctl with data.block[0] greater than I2C_SMBUS_BLOCK_MAX + 1. This patch makes the code compliant with Documentation/i2c/dev-interface by raising an error when the requested size is larger than 32 bytes. Call Trace: [<ffffffff8139f695>] dump_stack+0x67/0x92 [<ffffffff811802a4>] panic+0xc5/0x1eb [<ffffffff810ecb5f>] ? vprintk_default+0x1f/0x30 [<ffffffff817456d3>] ? i2cdev_ioctl_smbus+0x303/0x320 [<ffffffff8109a68b>] __stack_chk_fail+0x1b/0x20 [<ffffffff817456d3>] i2cdev_ioctl_smbus+0x303/0x320 [<ffffffff81745aed>] i2cdev_ioctl+0x4d/0x1e0 [<ffffffff811f761a>] do_vfs_ioctl+0x2ba/0x490 [<ffffffff81336e43>] ? security_file_ioctl+0x43/0x60 [<ffffffff811f7869>] SyS_ioctl+0x79/0x90 [<ffffffff81a22e97>] entry_SYSCALL_64_fastpath+0x12/0x6a Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Cc: stable@kernel.org
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/i2c-core-smbus.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index 4bb9927afd01..a1082c04ac5c 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -397,16 +397,17 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
the underlying bus driver */
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
+ if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
+ dev_err(&adapter->dev, "Invalid block %s size %d\n",
+ read_write == I2C_SMBUS_READ ? "read" : "write",
+ data->block[0]);
+ return -EINVAL;
+ }
+
if (read_write == I2C_SMBUS_READ) {
msg[1].len = data->block[0];
} else {
msg[0].len = data->block[0] + 1;
- if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
- dev_err(&adapter->dev,
- "Invalid block write size %d\n",
- data->block[0]);
- return -EINVAL;
- }
for (i = 1; i <= data->block[0]; i++)
msgbuf0[i] = data->block[i];
}

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