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authorKees Cook <keescook@chromium.org>2018-08-15 12:14:05 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-22 07:48:38 +0200
commit3b6393e30ec95bb5044cb4506ac468fb08ccf647 (patch)
treed75af3b08fbfd558f1389b73d69bc1c8175f115d
parent9aeef6b667f2ffc4c5725ea05e180e62fb307a31 (diff)
isdn: Disable IIOCDBGVAR
[ Upstream commit 5e22002aa8809e2efab2da95855f73f63e14a36c ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 e4c43a17b333..8088c34336aa 100644
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -1655,13 +1655,7 @@ 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;