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liveupdate: luo_core: fix redundant bound check in luo_ioctl() 

The kernel test robot reported a Smatch warning:
kernel/liveupdate/luo_core.c:402 luo_ioctl() warn: unsigned 'nr' is
never less than zero.

This occurs because 'nr' is unsigned and LIVEUPDATE_CMD_BASE is currently
defined as 0, making the check (nr < LIVEUPDATE_CMD_BASE) always false.

Remove the explicit lower bound check.  The logic remains correct because
'nr' is unsigned; if nr is less than LIVEUPDATE_CMD_BASE, the expression
(nr - LIVEUPDATE_CMD_BASE) will wrap around to a large positive value. 
This will inevitably be larger than ARRAY_SIZE(luo_ioctl_ops) and be
caught by the upper bound check.

Link: https://lkml.kernel.org/r/20251130010919.1488230-1-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202511280300.6pvBmXUS-lkp@intel.com/
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: David Matlack <dmatlack@google.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
master
Pasha Tatashin 2025-11-29 20:09:19 -05:00 committed by Andrew Morton
parent 2a4f33430e
commit bf2c7bf5c4
1 changed files with 1 additions and 3 deletions
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4
kernel/liveupdate/luo_core.c
View File

@ -399,10 +399,8 @@ static long luo_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
int err;
nr = _IOC_NR(cmd);
if (nr < LIVEUPDATE_CMD_BASE ||
(nr - LIVEUPDATE_CMD_BASE) >= ARRAY_SIZE(luo_ioctl_ops)) {
if (nr - LIVEUPDATE_CMD_BASE >= ARRAY_SIZE(luo_ioctl_ops))
return -EINVAL;
}
ucmd.ubuffer = (void __user *)arg;
err = get_user(ucmd.user_size, (u32 __user *)ucmd.ubuffer);