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diff -ur unionfs-1.1.5.ori/inode.c unionfs-1.1.5/inode.c
--- unionfs-1.1.5.ori/inode.c 2006-06-12 04:03:36.000000000 +0200
+++ unionfs-1.1.5/inode.c 2006-08-30 08:48:02.000000000 +0200
@@ -867,8 +867,43 @@
retval = generic_permission(inode, submask, NULL);
#endif
}
-
- if (retval && retval != -EROFS) /* ignore EROFS */
+
+ /* XXX jg
+ * Ignore EROFS but still perform the DAC check.
+ * This block of code added to work around RHEL 4 U3 problem
+ * Where all permission checks would return EROFS on readonly
+ * file system, and then be converted to 0 below. The
+ * result was anyone could write to any file before copyup!
+ * Code mostly lifted from fs/namei.c::vfs_permission().
+ */
+ if (retval == -EROFS) {
+ umode_t mode = inode->i_mode;
+
+ BUG_ON(bindex == 0); /* handled above */
+ if (current->fsuid == inode->i_uid)
+ mode >>= 6;
+ else if (in_group_p(inode->i_gid))
+ mode >>= 3;
+ if (((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask)) {
+ retval = 0;
+ goto out;
+ }
+ if (!(mask & MAY_EXEC) ||
+ (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode))
+ if (capable(CAP_DAC_OVERRIDE)) {
+ retval = 0;
+ goto out;
+ }
+ if (mask == MAY_READ ||
+ (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
+ if (capable(CAP_DAC_READ_SEARCH)) {
+ retval = 0;
+ goto out;
+ }
+ retval = -EACCES;
+ }
+out:
+ if (retval && retval != -EROFS) /* ignore EROFS */
return retval;
retval = security_inode_permission(inode, mask, nd);