| Message ID | 1288464922-8812-1-git-send-email-segooon@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On 30.10.2010, at 11:55, Vasiliy Kulikov wrote: > Structure kvm_ppc_pvinfo is copied to userland with "flags" and "pad" > fields unitialized. It leads to leaking of contents of kernel stack > memory. We have to initialize them to zero. > > In patch v1 Jan Kiszka suggested to fill reserved fields with zeros > instead of memset'ting the whole struct. It makes sense as these > fields are explicitly marked as padding. No more fields need zeroing. > > Signed-off-by: Vasiliy Kulikov <segooon@gmail.com> > --- > arch/powerpc/kvm/powerpc.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c > index 2f87a16..5962336 100644 > --- a/arch/powerpc/kvm/powerpc.c > +++ b/arch/powerpc/kvm/powerpc.c > @@ -604,6 +604,8 @@ static int kvm_vm_ioctl_get_pvinfo(struct kvm_ppc_pvinfo *pvinfo) > pvinfo->hcall[1] = inst_ori | (KVM_SC_MAGIC_R0 & inst_imm_mask); > pvinfo->hcall[2] = inst_sc; > pvinfo->hcall[3] = inst_nop; > + pvinfo->flags = 0; > + memset(&pvinfo->pad, 0, sizeof(pvinfo->pad)); This should only be memset(pvinfo->pad), no? It's an array after all which automatically translates to a pointer when referenced. Alex
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 2f87a16..5962336 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -604,6 +604,8 @@ static int kvm_vm_ioctl_get_pvinfo(struct kvm_ppc_pvinfo *pvinfo) pvinfo->hcall[1] = inst_ori | (KVM_SC_MAGIC_R0 & inst_imm_mask); pvinfo->hcall[2] = inst_sc; pvinfo->hcall[3] = inst_nop; + pvinfo->flags = 0; + memset(&pvinfo->pad, 0, sizeof(pvinfo->pad)); return 0; }
Structure kvm_ppc_pvinfo is copied to userland with "flags" and "pad" fields unitialized. It leads to leaking of contents of kernel stack memory. We have to initialize them to zero. In patch v1 Jan Kiszka suggested to fill reserved fields with zeros instead of memset'ting the whole struct. It makes sense as these fields are explicitly marked as padding. No more fields need zeroing. Signed-off-by: Vasiliy Kulikov <segooon@gmail.com> --- arch/powerpc/kvm/powerpc.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-)