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: <sta...@vger.kernel.org>
Cc: "Eric W. Biederman" <ebied...@xmission.com>
Signed-off-by: Aleksa Sarai <asa...@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

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