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authorColin Ian King <colin.king@canonical.com>2018-12-18 17:29:56 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-12-29 13:40:15 +0100
commit0d5fec5bda277187fc372fbd595cf78ec2345d15 (patch)
tree4b73c0649505093090c19ee0ca8d430cf8820c7d
parentdac731412750b9f1a8abd2f7032ee0be841ed406 (diff)
x86/mtrr: Don't copy uninitialized gentry fields back to userspace
commit 32043fa065b51e0b1433e48d118821c71b5cd65d upstream. Currently the copy_to_user of data in the gentry struct is copying uninitiaized data in field _pad from the stack to userspace. Fix this by explicitly memset'ing gentry to zero, this also will zero any compiler added padding fields that may be in struct (currently there are none). Detected by CoverityScan, CID#200783 ("Uninitialized scalar variable") Fixes: b263b31e8ad6 ("x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Tyler Hicks <tyhicks@canonical.com> Cc: security@kernel.org Link: https://lkml.kernel.org/r/20181218172956.1440-1-colin.king@canonical.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kernel/cpu/mtrr/if.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index 6d9b45549109..d5b2a08e2b66 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -172,6 +172,8 @@ mtrr_ioctl(struct file *file, unsigned int cmd, unsigned long __arg)
struct mtrr_gentry gentry;
void __user *arg = (void __user *) __arg;
+ memset(&gentry, 0, sizeof(gentry));
+
switch (cmd) {
case MTRRIOC_ADD_ENTRY:
case MTRRIOC_SET_ENTRY: