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

Nikita Zhandarovich
2025-01-15T16:42:38Z

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)))
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)
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;