From f58ba889106af60f52af792efbe1973e458a2138 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 2 Jul 2008 21:12:01 +0200 Subject: [GFS2] don't call permission() GFS2 calls permission() to verify permissions after locks on the files have been taken. For this it's sufficient to call gfs2_permission() instead. This results in the following changes: - IS_RDONLY() check is not performed - IS_IMMUTABLE() check is not performed - devcgroup_inode_permission() is not called - security_inode_permission() is not called IS_RDONLY() should be unnecessary anyway, as the per-mount read-only flag should provide protection against read-only remounts during operations. do_gfs2_set_flags() has been fixed to perform mnt_want_write()/mnt_drop_write() to protect against remounting read-only. IS_IMMUTABLE has been added to gfs2_permission() Repeating the security checks seems to be pointless, as they don't normally change, and if they do, it's independent of the filesystem state. Signed-off-by: Miklos Szeredi Signed-off-by: Steven Whitehouse --- fs/gfs2/inode.c | 6 +++--- fs/gfs2/inode.h | 1 + fs/gfs2/ops_file.c | 11 +++++++++-- fs/gfs2/ops_inode.c | 25 +++++++++++++++++-------- 4 files changed, 30 insertions(+), 13 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c index 09453d057e4..caf40908335 100644 --- a/fs/gfs2/inode.c +++ b/fs/gfs2/inode.c @@ -504,7 +504,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name, } if (!is_root) { - error = permission(dir, MAY_EXEC, NULL); + error = gfs2_permission(dir, MAY_EXEC); if (error) goto out; } @@ -667,7 +667,7 @@ static int create_ok(struct gfs2_inode *dip, const struct qstr *name, { int error; - error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL); + error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC); if (error) return error; @@ -1134,7 +1134,7 @@ int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name, if (IS_APPEND(&dip->i_inode)) return -EPERM; - error = permission(&dip->i_inode, MAY_WRITE | MAY_EXEC, NULL); + error = gfs2_permission(&dip->i_inode, MAY_WRITE | MAY_EXEC); if (error) return error; diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h index 580da454b38..04e9fef3f99 100644 --- a/fs/gfs2/inode.h +++ b/fs/gfs2/inode.h @@ -91,6 +91,7 @@ int gfs2_rmdiri(struct gfs2_inode *dip, const struct qstr *name, struct gfs2_inode *ip); int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name, const struct gfs2_inode *ip); +int gfs2_permission(struct inode *inode, int mask); int gfs2_ok_to_move(struct gfs2_inode *this, struct gfs2_inode *to); int gfs2_readlinki(struct gfs2_inode *ip, char **buf, unsigned int *len); int gfs2_glock_nq_atime(struct gfs2_holder *gh); diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index 0ff512a1192..1737af98a42 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -220,10 +221,14 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask) int error; u32 new_flags, flags; - error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh); + error = mnt_want_write(filp->f_path.mnt); if (error) return error; + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh); + if (error) + goto out_drop_write; + flags = ip->i_di.di_flags; new_flags = (flags & ~mask) | (reqflags & mask); if ((new_flags ^ flags) == 0) @@ -242,7 +247,7 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask) !capable(CAP_LINUX_IMMUTABLE)) goto out; if (!IS_IMMUTABLE(inode)) { - error = permission(inode, MAY_WRITE, NULL); + error = gfs2_permission(inode, MAY_WRITE); if (error) goto out; } @@ -272,6 +277,8 @@ out_trans_end: gfs2_trans_end(sdp); out: gfs2_glock_dq_uninit(&gh); +out_drop_write: + mnt_drop_write(filp->f_path.mnt); return error; } diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c index 2686ad4c002..1e252dfc529 100644 --- a/fs/gfs2/ops_inode.c +++ b/fs/gfs2/ops_inode.c @@ -163,7 +163,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir, if (error) goto out; - error = permission(dir, MAY_WRITE | MAY_EXEC, NULL); + error = gfs2_permission(dir, MAY_WRITE | MAY_EXEC); if (error) goto out_gunlock; @@ -669,7 +669,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry, } } } else { - error = permission(ndir, MAY_WRITE | MAY_EXEC, NULL); + error = gfs2_permission(ndir, MAY_WRITE | MAY_EXEC); if (error) goto out_gunlock; @@ -704,7 +704,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry, /* Check out the dir to be renamed */ if (dir_rename) { - error = permission(odentry->d_inode, MAY_WRITE, NULL); + error = gfs2_permission(odentry->d_inode, MAY_WRITE); if (error) goto out_gunlock; } @@ -891,7 +891,7 @@ static void *gfs2_follow_link(struct dentry *dentry, struct nameidata *nd) * Returns: errno */ -static int gfs2_permission(struct inode *inode, int mask, struct nameidata *nd) +int gfs2_permission(struct inode *inode, int mask) { struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_holder i_gh; @@ -905,13 +905,22 @@ static int gfs2_permission(struct inode *inode, int mask, struct nameidata *nd) unlock = 1; } - error = generic_permission(inode, mask, gfs2_check_acl); + if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode)) + error = -EACCES; + else + error = generic_permission(inode, mask, gfs2_check_acl); if (unlock) gfs2_glock_dq_uninit(&i_gh); return error; } +static int gfs2_iop_permission(struct inode *inode, int mask, + struct nameidata *nd) +{ + return gfs2_permission(inode, mask); +} + static int setattr_size(struct inode *inode, struct iattr *attr) { struct gfs2_inode *ip = GFS2_I(inode); @@ -1141,7 +1150,7 @@ static int gfs2_removexattr(struct dentry *dentry, const char *name) } const struct inode_operations gfs2_file_iops = { - .permission = gfs2_permission, + .permission = gfs2_iop_permission, .setattr = gfs2_setattr, .getattr = gfs2_getattr, .setxattr = gfs2_setxattr, @@ -1160,7 +1169,7 @@ const struct inode_operations gfs2_dir_iops = { .rmdir = gfs2_rmdir, .mknod = gfs2_mknod, .rename = gfs2_rename, - .permission = gfs2_permission, + .permission = gfs2_iop_permission, .setattr = gfs2_setattr, .getattr = gfs2_getattr, .setxattr = gfs2_setxattr, @@ -1172,7 +1181,7 @@ const struct inode_operations gfs2_dir_iops = { const struct inode_operations gfs2_symlink_iops = { .readlink = gfs2_readlink, .follow_link = gfs2_follow_link, - .permission = gfs2_permission, + .permission = gfs2_iop_permission, .setattr = gfs2_setattr, .getattr = gfs2_getattr, .setxattr = gfs2_setxattr, -- cgit v1.2.3