5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Christian Borntraeger <borntraeger@linux.ibm.com>
commit 4c07680a467e2f7697245bcd11691bffb2a6f0ed upstream.
struct kvm_hw_breakpoint::len is a __u64 that is fully controlled by user
space. This is then assigned to wp_info->len, which is an int. The bounds
check is done on the truncated value while the allocation uses the
untruncated one:
wp_info->len = bp_data->len;
[...]
if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE)
return -EINVAL;
wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL_ACCOUNT);
Use the validated value for the allocation as intended. Without this
fix userspace can trigger >4GB allocations which will fail and result
in a WARN due to MAX_PAGE_ORDER.
Fixes: 27291e2165b6 ("KVM: s390: hardware support for guest debugging")
Cc: <redacted>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-ID: [off-list ref]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/s390/kvm/guestdbg.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/s390/kvm/guestdbg.c
+++ b/arch/s390/kvm/guestdbg.c
@@ -184,7 +184,7 @@ static int __import_wp_info(struct kvm_v
if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE)
return -EINVAL;
- wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL_ACCOUNT);
+ wp_info->old_data = kmalloc(wp_info->len, GFP_KERNEL_ACCOUNT);
if (!wp_info->old_data)
return -ENOMEM;
/* try to backup the original value */