2019-07-07 00:46:41

by Zheng Bin

Subject: [PATCH v2] time: compat settimeofday: Validate the values of tv from user

Similar to commit 6ada1fc0e1c4
("time: settimeofday: Validate the values of tv from user"),
for a wide range of negative tv_usec values the multiplication overflow
turns them in positive numbers. So the 'validated later' is not catching
the invalid input.

Signed-off-by: zhengbin <[email protected]>
---
kernel/time/time.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/time/time.c b/kernel/time/time.c
index 7f7d691..5c54ca6 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -251,6 +251,10 @@ COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
if (tv) {
if (compat_get_timeval(&user_tv, tv))
return -EFAULT;
+
+ if (!timeval_valid(&user_tv))
+ return -EINVAL;
+
new_ts.tv_sec = user_tv.tv_sec;
new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
}
--
2.7.4

2019-07-07 10:46:28

by tip-bot for Vasyl Gomonovych

Subject: [tip:timers/core] time: Validate user input in compat_settimeofday()

Commit-ID: 9176ab1b848059a0cd9caf39f0cebaa1b7ec5ec2
Gitweb: https://git.kernel.org/tip/9176ab1b848059a0cd9caf39f0cebaa1b7ec5ec2
Author: zhengbin <[email protected]>
AuthorDate: Sun, 7 Jul 2019 08:51:41 +0800
Committer: Thomas Gleixner <[email protected]>
CommitDate: Sun, 7 Jul 2019 12:05:40 +0200

time: Validate user input in compat_settimeofday()

The user value is validated after converting the timeval to a timespec, but
for a wide range of negative tv_usec values the multiplication overflow turns
them in positive numbers. So the 'validated later' is not catching the
invalid input.

Signed-off-by: zhengbin <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

---
kernel/time/time.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/kernel/time/time.c b/kernel/time/time.c
index 7f7d6914ddd5..5c54ca632d08 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -251,6 +251,10 @@ COMPAT_SYSCALL_DEFINE2(settimeofday, struct old_timeval32 __user *, tv,
if (tv) {
if (compat_get_timeval(&user_tv, tv))
return -EFAULT;
+
+ if (!timeval_valid(&user_tv))
+ return -EINVAL;
+
new_ts.tv_sec = user_tv.tv_sec;
new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
}