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authorColin Ian King <colin.king@canonical.com>2018-12-18 17:29:56 +0000
committerThomas Gleixner <tglx@linutronix.de>2018-12-19 00:00:16 +0100
commit32043fa065b51e0b1433e48d118821c71b5cd65d (patch)
tree094fdcdbc7efd6d5eca4287755face6de178256c /arch
parent87ab4689ca6526079ab6f5150219ee88b42000ae (diff)
downloadlinux-32043fa065b51e0b1433e48d118821c71b5cd65d.tar.bz2
x86/mtrr: Don't copy uninitialized gentry fields back to userspace
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
Diffstat (limited to 'arch')
-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 2e173d47b450..4d36dcc1cf87 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -165,6 +165,8 @@ 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: