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author | Miklos Szeredi <mszeredi@redhat.com> | 2021-04-07 14:36:43 +0200 |
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committer | Miklos Szeredi <mszeredi@redhat.com> | 2021-04-12 15:04:29 +0200 |
commit | 66dbfabf10d3cb68ee01df60b11c0b3777a4217b (patch) | |
tree | a25c71b81c32dd64769108c9b0125c8b8e5715f0 /fs/overlayfs/inode.c | |
parent | 97e2dee9752bbd0eddfaec47e8036d35947521d9 (diff) | |
download | linux-stable-66dbfabf10d3cb68ee01df60b11c0b3777a4217b.tar.gz linux-stable-66dbfabf10d3cb68ee01df60b11c0b3777a4217b.tar.bz2 linux-stable-66dbfabf10d3cb68ee01df60b11c0b3777a4217b.zip |
ovl: stack fileattr ops
Add stacking for the fileattr operations.
Add hack for calling security_file_ioctl() for now. Probably better to
have a pair of specific hooks for these operations.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/inode.c')
-rw-r--r-- | fs/overlayfs/inode.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 003cf83bf78a..c3c96b4b3b33 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -11,6 +11,8 @@ #include <linux/posix_acl.h> #include <linux/ratelimit.h> #include <linux/fiemap.h> +#include <linux/fileattr.h> +#include <linux/security.h> #include "overlayfs.h" @@ -500,6 +502,79 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, return err; } +/* + * Work around the fact that security_file_ioctl() takes a file argument. + * Introducing security_inode_fileattr_get/set() hooks would solve this issue + * properly. + */ +static int ovl_security_fileattr(struct dentry *dentry, struct fileattr *fa, + bool set) +{ + struct path realpath; + struct file *file; + unsigned int cmd; + int err; + + ovl_path_real(dentry, &realpath); + file = dentry_open(&realpath, O_RDONLY, current_cred()); + if (IS_ERR(file)) + return PTR_ERR(file); + + if (set) + cmd = fa->fsx_valid ? FS_IOC_FSSETXATTR : FS_IOC_SETFLAGS; + else + cmd = fa->fsx_valid ? FS_IOC_FSGETXATTR : FS_IOC_GETFLAGS; + + err = security_file_ioctl(file, cmd, 0); + fput(file); + + return err; +} + +int ovl_fileattr_set(struct user_namespace *mnt_userns, + struct dentry *dentry, struct fileattr *fa) +{ + struct inode *inode = d_inode(dentry); + struct dentry *upperdentry; + const struct cred *old_cred; + int err; + + err = ovl_want_write(dentry); + if (err) + goto out; + + err = ovl_copy_up(dentry); + if (!err) { + upperdentry = ovl_dentry_upper(dentry); + + old_cred = ovl_override_creds(inode->i_sb); + err = ovl_security_fileattr(dentry, fa, true); + if (!err) + err = vfs_fileattr_set(&init_user_ns, upperdentry, fa); + revert_creds(old_cred); + ovl_copyflags(ovl_inode_real(inode), inode); + } + ovl_drop_write(dentry); +out: + return err; +} + +int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa) +{ + struct inode *inode = d_inode(dentry); + struct dentry *realdentry = ovl_dentry_real(dentry); + const struct cred *old_cred; + int err; + + old_cred = ovl_override_creds(inode->i_sb); + err = ovl_security_fileattr(dentry, fa, false); + if (!err) + err = vfs_fileattr_get(realdentry, fa); + revert_creds(old_cred); + + return err; +} + static const struct inode_operations ovl_file_inode_operations = { .setattr = ovl_setattr, .permission = ovl_permission, @@ -508,6 +583,8 @@ static const struct inode_operations ovl_file_inode_operations = { .get_acl = ovl_get_acl, .update_time = ovl_update_time, .fiemap = ovl_fiemap, + .fileattr_get = ovl_fileattr_get, + .fileattr_set = ovl_fileattr_set, }; static const struct inode_operations ovl_symlink_inode_operations = { |