[PATCH] cifs: fix potential overflow in cifs_compose_mount_options

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

[PATCH] cifs: fix potential overflow in cifs_compose_mount_options

Insu Yun
In worst case, "ip=" + sb_mountdata + ipv6 can be copied into mountdata.
Therefore, for safe, it is better to add more size when allocating memory.

Signed-off-by: Insu Yun <[hidden email]>
---
 fs/cifs/cifs_dfs_ref.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index 7dc886c..e956cba 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -175,7 +175,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
  * string to the length of the original string to allow for worst case.
  */
  md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
- mountdata = kzalloc(md_len + 1, GFP_KERNEL);
+ mountdata = kzalloc(md_len + sizeof("ip=") + 1, GFP_KERNEL);
  if (mountdata == NULL) {
  rc = -ENOMEM;
  goto compose_mount_options_err;
--
1.9.1

Reply | Threaded
Open this post in threaded view
|

Re: [PATCH] cifs: fix potential overflow in cifs_compose_mount_options

Steve French-2
On Mon, Feb 1, 2016 at 10:34 AM, Insu Yun <[hidden email]> wrote:

> In worst case, "ip=" + sb_mountdata + ipv6 can be copied into mountdata.
> Therefore, for safe, it is better to add more size when allocating memory.
>
> Signed-off-by: Insu Yun <[hidden email]>
> ---
>  fs/cifs/cifs_dfs_ref.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
> index 7dc886c..e956cba 100644
> --- a/fs/cifs/cifs_dfs_ref.c
> +++ b/fs/cifs/cifs_dfs_ref.c
> @@ -175,7 +175,7 @@ char *cifs_compose_mount_options(const char *sb_mountdata,
>          * string to the length of the original string to allow for worst case.
>          */
>         md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
> -       mountdata = kzalloc(md_len + 1, GFP_KERNEL);
> +       mountdata = kzalloc(md_len + sizeof("ip=") + 1, GFP_KERNEL);
>         if (mountdata == NULL) {
>                 rc = -ENOMEM;
>                 goto compose_mount_options_err;

Not likely to be reproducible in practice (since ip= is already in the
sb_mountdata) but in case mount.cifs was missing and ip= was missing from
the original mount string, might as well add it.

Merged into cifs-2.6.git


--
Thanks,

Steve