Re: [PATCH net] net/rose: prevent integer overflows in rose_setsockopt()

On 2025/1/16 07:29, David Laight wrote:

On Wed, 15 Jan 2025 08:42:20 -0800 Nikita Zhandarovich n.zhandarovich@fintech.ru wrote:

...

In case of possible unpredictably large arguments passed to rose_setsockopt() and multiplied by extra values on top of that, integer overflows may occur.

Do the safest minimum and fix these issues by checking the contents of 'opt' and returning -EINVAL if they are too large. Also, switch to unsigned int and remove useless check for negative 'opt' in ROSE_IDLE case.

Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru

---

net/rose/af_rose.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index 59050caab65c..72c65d938a15 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -397,15 +397,15 @@ static int rose_setsockopt(struct socket *sock, int level, int optname, { struct sock *sk = sock->sk; struct rose_sock *rose = rose_sk(sk);

• int opt;

• unsigned int opt;

if (level != SOL_ROSE) return -ENOPROTOOPT;

• if (optlen < sizeof(int))

• if (optlen < sizeof(unsigned int)) return -EINVAL;

• if (copy_from_sockptr(&opt, optval, sizeof(int)))

• if (copy_from_sockptr(&opt, optval, sizeof(unsigned int)))

Shouldn't all those be 'sizeof (opt)' ?

David

...

return -EFAULT;

switch (optname) { @@ -414,31 +414,31 @@ static int rose_setsockopt(struct socket *sock, int level, int optname, return 0; case ROSE_T1:

• if (opt < 1)
  

• if (opt < 1 || opt > UINT_MAX / HZ)
  

'rose->t1' is unsigned long, how about 'opt > ULONG_MAX / HZ' ?

BTW, I think only in 32bit or 16bit machine when 'sizeof(int) == sizeof(unsigned long)', this integer overflows may occur..

Su Hui

...

	return -EINVAL;
rose->t1 = opt * HZ;
return 0;

case ROSE_T2:

• if (opt < 1)
  

• if (opt < 1 || opt > UINT_MAX / HZ)
  return -EINVAL;
  

  rose->t2 = opt * HZ; return 0;

case ROSE_T3:

• if (opt < 1)
  

• if (opt < 1 || opt > UINT_MAX / HZ)
  return -EINVAL;
  

  rose->t3 = opt * HZ; return 0;

case ROSE_HOLDBACK:

• if (opt < 1)
  

• if (opt < 1 || opt > UINT_MAX / HZ)
  return -EINVAL;
  

  rose->hb = opt * HZ; return 0;

case ROSE_IDLE:

• if (opt < 0)
  

• if (opt > UINT_MAX / (60 * HZ))
  return -EINVAL;
  

  rose->idle = opt * 60 * HZ; return 0;