diff options
| author | Pasha Tatashin <pasha.tatashin@soleen.com> | 2025-11-29 20:09:19 -0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-12-10 16:07:42 -0800 |
| commit | bf2c7bf5c48303b76f20537238292571e6aa29f3 (patch) | |
| tree | 945df81e8398e679c37cbf4e4e240bd046cd4c15 /kernel | |
| parent | 2a4f33430e96d0bebfa37b1d586098f61f030b06 (diff) | |
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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/liveupdate/luo_core.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c index f7ecaf7740d1..944663d99dd9 100644 --- a/kernel/liveupdate/luo_core.c +++ b/kernel/liveupdate/luo_core.c @@ -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); |