[axboe:rw_iter 155/471] drivers/usb/chipidea/debug.c:89 ci_port_test_write() warn: potential spectre issue 'buf' [w]

[kernel test robot <lkp@intel.com>]

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
TO: Jens Axboe <axboe@kernel.dk>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git rw_iter
head:   0a49759be1c3b29207758e467fdc1a90d0716d06
commit: c08703a0ede98e3db453b782579c22892e8909ab [155/471] usb: chipidea: convert to read/write iterators
:::::: branch date: 6 days ago
:::::: commit date: 6 days ago
config: openrisc-randconfig-r071-20260307 (https://download.01.org/0day-ci/archive/20260312/202603121510.vaiHWvfx-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 15.2.0
smatch: v0.5.0-9004-gb810ac53

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>
| Closes: https://lore.kernel.org/r/202603121510.vaiHWvfx-lkp@intel.com/

smatch warnings:
drivers/usb/chipidea/debug.c:89 ci_port_test_write() warn: potential spectre issue 'buf' [w]

vim +/buf +89 drivers/usb/chipidea/debug.c

e443b333629f82c Alexander Shishkin  2012-05-11   70  
5722a8efc6c8979 Lee Jones           2020-07-03   71  /*
2d6512892c10655 Alexander Shishkin  2013-03-30   72   * ci_port_test_write: writes port test mode
e443b333629f82c Alexander Shishkin  2012-05-11   73   */
c08703a0ede98e3 Jens Axboe          2024-04-11   74  static ssize_t ci_port_test_write(struct kiocb *iocb, struct iov_iter *from)
e443b333629f82c Alexander Shishkin  2012-05-11   75  {
c08703a0ede98e3 Jens Axboe          2024-04-11   76  	struct seq_file *s = iocb->ki_filp->private_data;
c08703a0ede98e3 Jens Axboe          2024-04-11   77  	size_t count = iov_iter_count(from);
8e22978c57087aa Alexander Shishkin  2013-06-24   78  	struct ci_hdrc *ci = s->private;
e443b333629f82c Alexander Shishkin  2012-05-11   79  	unsigned long flags;
e443b333629f82c Alexander Shishkin  2012-05-11   80  	unsigned mode;
2d6512892c10655 Alexander Shishkin  2013-03-30   81  	char buf[32];
2d6512892c10655 Alexander Shishkin  2013-03-30   82  	int ret;
e443b333629f82c Alexander Shishkin  2012-05-11   83  
bd5fb0aec3dd7cd Heinrich Schuchardt 2015-04-28   84  	count = min_t(size_t, sizeof(buf) - 1, count);
c08703a0ede98e3 Jens Axboe          2024-04-11   85  	if (!copy_from_iter_full(buf, count, from))
2d6512892c10655 Alexander Shishkin  2013-03-30   86  		return -EFAULT;
e443b333629f82c Alexander Shishkin  2012-05-11   87  
bd5fb0aec3dd7cd Heinrich Schuchardt 2015-04-28   88  	/* sscanf requires a zero terminated string */
bd5fb0aec3dd7cd Heinrich Schuchardt 2015-04-28  @89  	buf[count] = '\0';
bd5fb0aec3dd7cd Heinrich Schuchardt 2015-04-28   90  
2d6512892c10655 Alexander Shishkin  2013-03-30   91  	if (sscanf(buf, "%u", &mode) != 1)
2d6512892c10655 Alexander Shishkin  2013-03-30   92  		return -EINVAL;
e443b333629f82c Alexander Shishkin  2012-05-11   93  
3c724888d2b1e08 Alan                2016-02-15   94  	if (mode > 255)
3c724888d2b1e08 Alan                2016-02-15   95  		return -EBADRQC;
3c724888d2b1e08 Alan                2016-02-15   96  
bc24937943d9f71 Li Jun              2015-07-29   97  	pm_runtime_get_sync(ci->dev);
26c696c678c4ce1 Richard Zhao        2012-07-07   98  	spin_lock_irqsave(&ci->lock, flags);
2d6512892c10655 Alexander Shishkin  2013-03-30   99  	ret = hw_port_test_set(ci, mode);
26c696c678c4ce1 Richard Zhao        2012-07-07  100  	spin_unlock_irqrestore(&ci->lock, flags);
bc24937943d9f71 Li Jun              2015-07-29  101  	pm_runtime_put_sync(ci->dev);
e443b333629f82c Alexander Shishkin  2012-05-11  102  
2d6512892c10655 Alexander Shishkin  2013-03-30  103  	return ret ? ret : count;
e443b333629f82c Alexander Shishkin  2012-05-11  104  }
2d6512892c10655 Alexander Shishkin  2013-03-30  105  

:::::: The code at line 89 was first introduced by commit
:::::: bd5fb0aec3dd7cde7ec4c397b10e55d4c9626d8d usb: chipidea: debug: avoid out of bound read

:::::: TO: Heinrich Schuchardt <xypron.glpk@gmx.de>
:::::: CC: Peter Chen <peter.chen@freescale.com>

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki