* [PATCH] scsi: require CAP_SYS_ADMIN to write to procfs interface
@ 2017-11-04 18:59 Aleksa Sarai
2017-11-04 20:20 ` Randy Dunlap
0 siblings, 1 reply; 3+ messages in thread
From: Aleksa Sarai @ 2017-11-04 18:59 UTC (permalink / raw)
To: James E.J. Bottomley, Martin K. Petersen
Cc: linux-scsi, linux-kernel, containers, Valentin Rothberg, cyphar,
Aleksa Sarai, stable, Eric W. Biederman
Previously, the only capability effectively required to operate on the
/proc/scsi interface was CAP_DAC_OVERRIDE (or for some other files,
having an fsuid of GLOBAL_ROOT_UID was enough). This means that
semi-privileged processes could interfere with core components of a
system (such as causing a DoS by removing the underlying SCSI device of
the host's / mount).
Cc: <stable@vger.kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Aleksa Sarai <asarai@suse.de>
---
drivers/scsi/scsi_proc.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
index 480a597b3877..486aedce2f05 100644
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -51,7 +51,10 @@ static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf,
struct Scsi_Host *shost = PDE_DATA(file_inode(file));
ssize_t ret = -ENOMEM;
char *page;
-
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM
+
if (count > PROC_BLOCK_SIZE)
return -EOVERFLOW;
@@ -313,6 +316,9 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf,
char *buffer, *p;
int err;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
if (!buf || length > PAGE_SIZE)
return -EINVAL;
--
2.14.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] scsi: require CAP_SYS_ADMIN to write to procfs interface
2017-11-04 18:59 [PATCH] scsi: require CAP_SYS_ADMIN to write to procfs interface Aleksa Sarai
@ 2017-11-04 20:20 ` Randy Dunlap
[not found] ` <7595538b-c203-0af4-810e-e3f97334a314-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: Randy Dunlap @ 2017-11-04 20:20 UTC (permalink / raw)
To: Aleksa Sarai, James E.J. Bottomley, Martin K. Petersen
Cc: linux-scsi, linux-kernel, containers, Valentin Rothberg, cyphar,
stable, Eric W. Biederman
On 11/04/2017 11:59 AM, Aleksa Sarai wrote:
> Previously, the only capability effectively required to operate on the
> /proc/scsi interface was CAP_DAC_OVERRIDE (or for some other files,
> having an fsuid of GLOBAL_ROOT_UID was enough). This means that
> semi-privileged processes could interfere with core components of a
> system (such as causing a DoS by removing the underlying SCSI device of
> the host's / mount).
>
> Cc: <stable@vger.kernel.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Signed-off-by: Aleksa Sarai <asarai@suse.de>
> ---
> drivers/scsi/scsi_proc.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
> index 480a597b3877..486aedce2f05 100644
> --- a/drivers/scsi/scsi_proc.c
> +++ b/drivers/scsi/scsi_proc.c
> @@ -51,7 +51,10 @@ static ssize_t proc_scsi_host_write(struct file *file, const char __user *buf,
> struct Scsi_Host *shost = PDE_DATA(file_inode(file));
> ssize_t ret = -ENOMEM;
> char *page;
> -
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM
did that build without a trailing ';' ?
> +
> if (count > PROC_BLOCK_SIZE)
> return -EOVERFLOW;
>
> @@ -313,6 +316,9 @@ static ssize_t proc_scsi_write(struct file *file, const char __user *buf,
> char *buffer, *p;
> int err;
>
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> if (!buf || length > PAGE_SIZE)
> return -EINVAL;
>
>
--
~Randy
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-11-04 18:59 [PATCH] scsi: require CAP_SYS_ADMIN to write to procfs interface Aleksa Sarai
2017-11-04 20:20 ` Randy Dunlap
[not found] ` <7595538b-c203-0af4-810e-e3f97334a314-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2017-11-04 20:26 ` Aleksa Sarai
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