2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Martin Schwidefsky upstream commit: 58984ce21d315b70df1a43644df7416ea7c9bfd8 The calculation of the value nr in do_xip_mapping_read is incorrect. If the copy required more than one iteration in the do while loop the copies variable will be non-zero. The maximum length that may be passed to the call to copy_to_user(buf+copied, xip_mem+offset, nr) is len-copied but the check only compares against (nr > len). This bug is the cause for the heap corruption Carsten has been chasing for so long: --- mm/filemap_xip.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -89,8 +89,8 @@ do_xip_mapping_read(struct address_space } } nr = nr - offset; - if (nr > len) - nr = len; + if (nr > len - copied) + nr = len - copied; error = mapping->a_ops->get_xip_mem(mapping, index, 0, &xip_mem, &xip_pfn); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/