From 0e363cf3fa598c69340794da068d4d9cbc869322 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 21 Jun 2022 16:14:53 +0200 Subject: security: pass down mount idmapping to setattr hook Before this change we used to take a shortcut and place the actual values that would be written to inode->i_{g,u}id into struct iattr. This had the advantage that we moved idmappings mostly out of the picture early on but it made reasoning about changes more difficult than it should be. The filesystem was never explicitly told that it dealt with an idmapped mount. The transition to the value that needed to be stored in inode->i_{g,u}id appeared way too early and increased the probability of bugs in various codepaths. We know place the same value in struct iattr no matter if this is an idmapped mount or not. The vfs will only deal with type safe vfs{g,u}id_t. This makes it massively safer to perform permission checks as the type will tell us what checks we need to perform and what helpers we need to use. Adapt the security_inode_setattr() helper to pass down the mount's idmapping to account for that change. Link: https://lore.kernel.org/r/20220621141454.2914719-8-brauner@kernel.org Cc: Seth Forshee Cc: Christoph Hellwig Cc: Aleksa Sarai Cc: Linus Torvalds Cc: Al Viro CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee Signed-off-by: Christian Brauner (Microsoft) --- include/linux/security.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/linux/security.h') diff --git a/include/linux/security.h b/include/linux/security.h index 7fc4e9f49f54..4d0baf30266e 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -353,7 +353,8 @@ int security_inode_readlink(struct dentry *dentry); int security_inode_follow_link(struct dentry *dentry, struct inode *inode, bool rcu); int security_inode_permission(struct inode *inode, int mask); -int security_inode_setattr(struct dentry *dentry, struct iattr *attr); +int security_inode_setattr(struct user_namespace *mnt_userns, + struct dentry *dentry, struct iattr *attr); int security_inode_getattr(const struct path *path); int security_inode_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, const char *name, @@ -848,8 +849,9 @@ static inline int security_inode_permission(struct inode *inode, int mask) return 0; } -static inline int security_inode_setattr(struct dentry *dentry, - struct iattr *attr) +static inline int security_inode_setattr(struct user_namespace *mnt_userns, + struct dentry *dentry, + struct iattr *attr) { return 0; } -- cgit v1.2.3 From fcfe0ac2fcfae7d5fcad3d0375cb8ff38caf8aba Mon Sep 17 00:00:00 2001 From: Micah Morton Date: Wed, 8 Jun 2022 20:57:11 +0000 Subject: security: Add LSM hook to setgroups() syscall Give the LSM framework the ability to filter setgroups() syscalls. There are already analagous hooks for the set*uid() and set*gid() syscalls. The SafeSetID LSM will use this new hook to ensure setgroups() calls are allowed by the installed security policy. Tested by putting print statement in security_task_fix_setgroups() hook and confirming that it gets hit when userspace does a setgroups() syscall. Acked-by: Casey Schaufler Reviewed-by: Serge Hallyn Signed-off-by: Micah Morton --- include/linux/security.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/security.h') diff --git a/include/linux/security.h b/include/linux/security.h index 7fc4e9f49f54..1dfd32c49fa3 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -415,6 +415,7 @@ int security_task_fix_setuid(struct cred *new, const struct cred *old, int flags); int security_task_fix_setgid(struct cred *new, const struct cred *old, int flags); +int security_task_fix_setgroups(struct cred *new, const struct cred *old); int security_task_setpgid(struct task_struct *p, pid_t pgid); int security_task_getpgid(struct task_struct *p); int security_task_getsid(struct task_struct *p); @@ -1098,6 +1099,12 @@ static inline int security_task_fix_setgid(struct cred *new, return 0; } +static inline int security_task_fix_setgroups(struct cred *new, + const struct cred *old) +{ + return 0; +} + static inline int security_task_setpgid(struct task_struct *p, pid_t pgid) { return 0; -- cgit v1.2.3 From 2a5840124009f133bd09fd855963551fb2cefe22 Mon Sep 17 00:00:00 2001 From: Luis Chamberlain Date: Fri, 15 Jul 2022 12:16:22 -0700 Subject: lsm,io_uring: add LSM hooks for the new uring_cmd file op io-uring cmd support was added through ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd"), this extended the struct file_operations to allow a new command which each subsystem can use to enable command passthrough. Add an LSM specific for the command passthrough which enables LSMs to inspect the command details. This was discussed long ago without no clear pointer for something conclusive, so this enables LSMs to at least reject this new file operation. [0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com Cc: stable@vger.kernel.org Fixes: ee692a21e9bf ("fs,io_uring: add infrastructure for uring-cmd") Signed-off-by: Luis Chamberlain Acked-by: Jens Axboe Signed-off-by: Paul Moore --- include/linux/security.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/security.h') diff --git a/include/linux/security.h b/include/linux/security.h index 1bc362cb413f..7bd0c490703d 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -2060,6 +2060,7 @@ static inline int security_perf_event_write(struct perf_event *event) #ifdef CONFIG_SECURITY extern int security_uring_override_creds(const struct cred *new); extern int security_uring_sqpoll(void); +extern int security_uring_cmd(struct io_uring_cmd *ioucmd); #else static inline int security_uring_override_creds(const struct cred *new) { @@ -2069,6 +2070,10 @@ static inline int security_uring_sqpoll(void) { return 0; } +static inline int security_uring_cmd(struct io_uring_cmd *ioucmd) +{ + return 0; +} #endif /* CONFIG_SECURITY */ #endif /* CONFIG_IO_URING */ -- cgit v1.2.3