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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-12 16:54:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-12 16:54:37 -0700
commit5010fe9f095414b959fd6fda63986dc90fd0c419 (patch)
tree83de620958908e92c567af5fc773768c9f46ada2 /fs/inode.c
parent8487d8229990e6eacaf1c854a113c9d16b7b596c (diff)
parentdbc77f31e58b2902a5e7643761c04bf69f57a32a (diff)
Merge tag 'vfs-fix-ioctl-checking-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull common SETFLAGS/FSSETXATTR parameter checking from Darrick Wong: "Here's a patch series that sets up common parameter checking functions for the FS_IOC_SETFLAGS and FS_IOC_FSSETXATTR ioctl implementations. The goal here is to reduce the amount of behaviorial variance between the filesystems where those ioctls originated (ext2 and XFS, respectively) and everybody else. - Standardize parameter checking for the SETFLAGS and FSSETXATTR ioctls (which were the file attribute setters for ext4 and xfs and have now been hoisted to the vfs) - Only allow the DAX flag to be set on files and directories" * tag 'vfs-fix-ioctl-checking-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: vfs: only allow FSSETXATTR to set DAX flag on files and dirs vfs: teach vfs_ioc_fssetxattr_check to check extent size hints vfs: teach vfs_ioc_fssetxattr_check to check project id info vfs: create a generic checking function for FS_IOC_FSSETXATTR vfs: create a generic checking and prep function for FS_IOC_SETFLAGS
Diffstat (limited to 'fs/inode.c')
-rw-r--r--fs/inode.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 5f5431ec3d62..0f1e3b563c47 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2190,3 +2190,89 @@ struct timespec64 current_time(struct inode *inode)
return timespec64_trunc(now, inode->i_sb->s_time_gran);
}
EXPORT_SYMBOL(current_time);
+
+/*
+ * Generic function to check FS_IOC_SETFLAGS values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
+ unsigned int flags)
+{
+ /*
+ * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+ * the relevant capability.
+ *
+ * This test looks nicer. Thanks to Pauline Middelink
+ */
+ if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
+ !capable(CAP_LINUX_IMMUTABLE))
+ return -EPERM;
+
+ return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_setflags_prepare);
+
+/*
+ * Generic function to check FS_IOC_FSSETXATTR values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
+ struct fsxattr *fa)
+{
+ /*
+ * Can't modify an immutable/append-only file unless we have
+ * appropriate permission.
+ */
+ if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
+ (FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND) &&
+ !capable(CAP_LINUX_IMMUTABLE))
+ return -EPERM;
+
+ /*
+ * Project Quota ID state is only allowed to change from within the init
+ * namespace. Enforce that restriction only if we are trying to change
+ * the quota ID state. Everything else is allowed in user namespaces.
+ */
+ if (current_user_ns() != &init_user_ns) {
+ if (old_fa->fsx_projid != fa->fsx_projid)
+ return -EINVAL;
+ if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
+ FS_XFLAG_PROJINHERIT)
+ return -EINVAL;
+ }
+
+ /* Check extent size hints. */
+ if ((fa->fsx_xflags & FS_XFLAG_EXTSIZE) && !S_ISREG(inode->i_mode))
+ return -EINVAL;
+
+ if ((fa->fsx_xflags & FS_XFLAG_EXTSZINHERIT) &&
+ !S_ISDIR(inode->i_mode))
+ return -EINVAL;
+
+ if ((fa->fsx_xflags & FS_XFLAG_COWEXTSIZE) &&
+ !S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
+ return -EINVAL;
+
+ /*
+ * It is only valid to set the DAX flag on regular files and
+ * directories on filesystems.
+ */
+ if ((fa->fsx_xflags & FS_XFLAG_DAX) &&
+ !(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)))
+ return -EINVAL;
+
+ /* Extent size hints of zero turn off the flags. */
+ if (fa->fsx_extsize == 0)
+ fa->fsx_xflags &= ~(FS_XFLAG_EXTSIZE | FS_XFLAG_EXTSZINHERIT);
+ if (fa->fsx_cowextsize == 0)
+ fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
+
+ return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_fssetxattr_check);