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Old 04-26-2011, 04:08 PM
Tim Gardner
 
Default Treat writes as new when holes span across page boundaries, CVE-2011-0463

On 04/26/2011 10:00 AM, Brad Figg wrote:

From: Goldwyn Rodrigues<rgoldwyn@gmail.com>

BugLink: http://bugs.launchpad.net/bugs/770483

CVE-2011-0463

When a hole spans across page boundaries, the next write forces
a read of the block. This could end up reading existing garbage
data from the disk in ocfs2_map_page_blocks. This leads to
non-zero holes. In order to avoid this, mark the writes as new
when the holes span across page boundaries.

Signed-off-by: Goldwyn Rodrigues<rgoldwyn@suse.de>
Signed-off-by: jlbec<jlbec@evilplan.org>

(cherry-pick of commit 272b62c1f0f6f742046e45b50b6fec98860208a0)
Signed-off-by: Brad Figg<brad.figg@canonical.com>
---
fs/ocfs2/aops.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 0d44b77..b5d7fb9 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1015,6 +1015,12 @@ static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
&cluster_start,&cluster_end);

+ /* treat the write as new if the a hole/lseek spanned across
+ * the page boundary.
+ */
+ new = new | ((i_size_read(inode)<= page_offset(page))&&
+ (page_offset(page)<= user_pos));
+
if (page == wc->w_target_page) {
map_from = user_pos& (PAGE_CACHE_SIZE - 1);
map_to = map_from + user_len;



Acked-by: Tim Gardner <tim.gardner@canonical.com>

--
Tim Gardner tim.gardner@canonical.com

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kernel-team mailing list
kernel-team@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/kernel-team
 
Old 04-26-2011, 04:21 PM
Tim Gardner
 
Default Treat writes as new when holes span across page boundaries, CVE-2011-0463

On 04/26/2011 10:00 AM, Brad Figg wrote:

From: Goldwyn Rodrigues<rgoldwyn@gmail.com>

BugLink: http://bugs.launchpad.net/bugs/770483

CVE-2011-0463

When a hole spans across page boundaries, the next write forces
a read of the block. This could end up reading existing garbage
data from the disk in ocfs2_map_page_blocks. This leads to
non-zero holes. In order to avoid this, mark the writes as new
when the holes span across page boundaries.

Signed-off-by: Goldwyn Rodrigues<rgoldwyn@suse.de>
Signed-off-by: jlbec<jlbec@evilplan.org>

(cherry-pick of commit 272b62c1f0f6f742046e45b50b6fec98860208a0)
Signed-off-by: Brad Figg<brad.figg@canonical.com>
---
fs/ocfs2/aops.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 0d44b77..b5d7fb9 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -1015,6 +1015,12 @@ static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
&cluster_start,&cluster_end);

+ /* treat the write as new if the a hole/lseek spanned across
+ * the page boundary.
+ */
+ new = new | ((i_size_read(inode)<= page_offset(page))&&
+ (page_offset(page)<= user_pos));
+
if (page == wc->w_target_page) {
map_from = user_pos& (PAGE_CACHE_SIZE - 1);
map_to = map_from + user_len;


applied to Hardy/Maverick

--
Tim Gardner tim.gardner@canonical.com

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