gfs2: preserve i_mode if __gfs2_set_acl() fails (309e8cda) · Commits · 戴 / test

When changing a file's acl mask, __gfs2_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl. If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users. Prevent this by only changing the inode mode after the acl has been set. Signed-off-by:

Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com> Signed-off-by:

Bob Peterson <rpeterso@redhat.com>

fs/gfs2/acl.c

+8 −5

Original line number	Diff line number	Diff line
		@@ -116,6 +116,7 @@ int gfs2_set_acl(struct inode inode, struct posix_acl acl, int type)
		struct gfs2_holder gh;
		bool need_unlock = false;
		int ret;
		umode_t mode;

		if (acl && acl->a_count > GFS2_ACL_MAX_ENTRIES(GFS2_SB(inode)))
		return -E2BIG;
		@@ -130,17 +131,19 @@ int gfs2_set_acl(struct inode inode, struct posix_acl acl, int type)
		return ret;
		need_unlock = true;
		}
		if (type == ACL_TYPE_ACCESS && acl) {
		umode_t mode = inode->i_mode;

		ret = posix_acl_update_mode(inode, &inode->i_mode, &acl);
		mode = inode->i_mode;
		if (type == ACL_TYPE_ACCESS && acl) {
		ret = posix_acl_update_mode(inode, &mode, &acl);
		if (ret)
		goto unlock;
		if (mode != inode->i_mode)
		mark_inode_dirty(inode);
		}

		ret = __gfs2_set_acl(inode, acl, type);
		if (!ret && mode != inode->i_mode) {
		inode->i_mode = mode;
		mark_inode_dirty(inode);
		}
		unlock:
		if (need_unlock)
		gfs2_glock_dq_uninit(&gh);

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