In a containerized environment, independent memory binding by a user can lead to unexpected system issues or disrupt tasks being run by other users on the same server. If a user genuinely requires memory binding, we will allocate dedicated servers to them by leveraging kubelet deployment. At present, users have the capability to bind their memory to a specific node without explicit agreement or authorization from us. Consequently, a new LSM hook is introduced to mitigate this. This implementation allows us to exercise fine-grained control over memory policy adjustments within our container environment Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> --- include/linux/lsm_hook_defs.h | 3 +++ include/linux/security.h | 9 +++++++++ mm/mempolicy.c | 8 ++++++++ security/security.c | 13 +++++++++++++ 4 files changed, 33 insertions(+) diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index ff217a5ce552..558012719f98 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -419,3 +419,6 @@ LSM_HOOK(int, 0, uring_override_creds, const struct cred *new) LSM_HOOK(int, 0, uring_sqpoll, void) LSM_HOOK(int, 0, uring_cmd, struct io_uring_cmd *ioucmd) #endif /* CONFIG_IO_URING */ + +LSM_HOOK(int, 0, set_mempolicy, unsigned long mode, unsigned short mode_flags, + nodemask_t *nmask, unsigned int flags) diff --git a/include/linux/security.h b/include/linux/security.h index 1d1df326c881..cc4a19a0888c 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -484,6 +484,8 @@ int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen); int security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen); int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen); int security_locked_down(enum lockdown_reason what); +int security_set_mempolicy(unsigned long mode, unsigned short mode_flags, + nodemask_t *nmask, unsigned int flags); #else /* CONFIG_SECURITY */ static inline int call_blocking_lsm_notifier(enum lsm_event event, void *data) @@ -1395,6 +1397,13 @@ static inline int security_locked_down(enum lockdown_reason what) { return 0; } + +static inline int +security_set_mempolicy(unsigned long mode, unsigned short mode_flags, + nodemask_t *nmask, unsigned int flags) +{ + return 0; +} #endif /* CONFIG_SECURITY */ #if defined(CONFIG_SECURITY) && defined(CONFIG_WATCH_QUEUE) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 1eafe81d782e..9a260dd24a4b 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1495,6 +1495,10 @@ static long kernel_mbind(unsigned long start, unsigned long len, if (err) return err; + err = security_set_mempolicy(lmode, mode_flags, &nodes, flags); + if (err) + return err; + return do_mbind(start, len, lmode, mode_flags, &nodes, flags); } @@ -1589,6 +1593,10 @@ static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask, if (err) return err; + err = security_set_mempolicy(lmode, mode_flags, &nodes, 0); + if (err) + return err; + return do_set_mempolicy(lmode, mode_flags, &nodes); } diff --git a/security/security.c b/security/security.c index dcb3e7014f9b..685ad7993753 100644 --- a/security/security.c +++ b/security/security.c @@ -5337,3 +5337,16 @@ int security_uring_cmd(struct io_uring_cmd *ioucmd) return call_int_hook(uring_cmd, 0, ioucmd); } #endif /* CONFIG_IO_URING */ + +/** + * security_set_mempolicy() - Check if memory policy can be adjusted + * @mode: The memory policy mode to be set + * @mode_flags: optional mode flags + * @nmask: modemask to which the mode applies + * @flags: mode flags for mbind(2) only + */ +int security_set_mempolicy(unsigned long mode, unsigned short mode_flags, + nodemask_t *nmask, unsigned int flags) +{ + return call_int_hook(set_mempolicy, 0, mode, mode_flags, nmask, flags); +} -- 2.30.1 (Apple Git-130)