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authorKees Cook <keescook@chromium.org>2018-08-15 21:14:05 +0200
committerDavid S. Miller <davem@davemloft.net>2018-08-16 21:26:24 +0200
commit5e22002aa8809e2efab2da95855f73f63e14a36c (patch)
tree24061c231a0719289e9613c3654132faafbf54b1 /drivers/isdn
parentnet: dsa: add support for ksz9897 ethernet switch (diff)
downloadlinux-5e22002aa8809e2efab2da95855f73f63e14a36c.tar.xz
linux-5e22002aa8809e2efab2da95855f73f63e14a36c.zip
isdn: Disable IIOCDBGVAR
It was possible to directly leak the kernel address where the isdn_dev structure pointer was stored. This is a kernel ASLR bypass for anyone with access to the ioctl. The code had been present since the beginning of git history, though this shouldn't ever be needed for normal operation, therefore remove it. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Karsten Keil <isdn@linux-pingi.de> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
-rw-r--r--drivers/isdn/i4l/isdn_common.c8
1 files changed, 1 insertions, 7 deletions
diff --git a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c
index 7a501dbe7123..6a5b3f00f9ad 100644
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -1640,13 +1640,7 @@ isdn_ioctl(struct file *file, uint cmd, ulong arg)
} else
return -EINVAL;
case IIOCDBGVAR:
- if (arg) {
- if (copy_to_user(argp, &dev, sizeof(ulong)))
- return -EFAULT;
- return 0;
- } else
- return -EINVAL;
- break;
+ return -EINVAL;
default:
if ((cmd & IIOCDRVCTL) == IIOCDRVCTL)
cmd = ((cmd >> _IOC_NRSHIFT) & _IOC_NRMASK) & ISDN_DRVIOCTL_MASK;