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| author | Chen Jie <chenjie6@huawei.com> | 2019-03-15 03:44:38 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-03-22 13:05:26 +0100 |
| commit | 5a07168d8d89b00fe1760120714378175b3ef992 (patch) | |
| tree | 6f3145c5c6965d7385b68dc46e7c3e710ccded13 | |
| parent | 82efcab3b9f3ef59e9713237c6e3c05c3a95c1ae (diff) | |
| download | linux-5a07168d8d89b00fe1760120714378175b3ef992.tar.bz2 | |
futex: Ensure that futex address is aligned in handle_futex_death()
The futex code requires that the user space addresses of futexes are 32bit
aligned. sys_futex() checks this in futex_get_keys() but the robust list
code has no alignment check in place.
As a consequence the kernel crashes on architectures with strict alignment
requirements in handle_futex_death() when trying to cmpxchg() on an
unaligned futex address which was retrieved from the robust list.
[ tglx: Rewrote changelog, proper sizeof() based alignement check and add
comment ]
Fixes: 0771dfefc9e5 ("[PATCH] lightweight robust futexes: core")
Signed-off-by: Chen Jie <chenjie6@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <dvhart@infradead.org>
Cc: <peterz@infradead.org>
Cc: <zengweilin@huawei.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1552621478-119787-1-git-send-email-chenjie6@huawei.com
| -rw-r--r-- | kernel/futex.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index c3b73b0311bc..9e40cf7be606 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -3436,6 +3436,10 @@ static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int p { u32 uval, uninitialized_var(nval), mval; + /* Futex address must be 32bit aligned */ + if ((((unsigned long)uaddr) % sizeof(*uaddr)) != 0) + return -1; + retry: if (get_user(uval, uaddr)) return -1; |