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| author | Guillaume Bertholon <guillaume.bertholon@ens.fr> | 2022-02-01 18:17:51 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-03 09:27:54 +0100 |
| commit | 52060aa13c85ef1acb53f0498bfcdf22e129ef51 (patch) | |
| tree | dccb696762006c46ccfb20117eec5af6857e676a | |
| parent | 1fa3bfc12bebafed63f992ed206ae434c1736f0d (diff) | |
| download | linux-stable-52060aa13c85ef1acb53f0498bfcdf22e129ef51.tar.gz linux-stable-52060aa13c85ef1acb53f0498bfcdf22e129ef51.tar.bz2 linux-stable-52060aa13c85ef1acb53f0498bfcdf22e129ef51.zip | |
KVM: x86: Fix misplaced backport of "work around leak of uninitialized stack contents"
The upstream commit 541ab2aeb282 ("KVM: x86: work around leak of
uninitialized stack contents") resets `exception` in the function
`kvm_write_guest_virt_system`.
However, its backported version in stable (commit ba7f1c934f2e
("KVM: x86: work around leak of uninitialized stack contents")) applied
the change in `emulator_write_std` instead.
This patch moves the memset instruction back to
`kvm_write_guest_virt_system`.
Fixes: ba7f1c934f2e ("KVM: x86: work around leak of uninitialized stack contents")
Signed-off-by: Guillaume Bertholon <guillaume.bertholon@ens.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kvm/x86.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8dce61ca934b..910100257df9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4417,13 +4417,6 @@ static int emulator_write_std(struct x86_emulate_ctxt *ctxt, gva_t addr, void *v if (!system && kvm_x86_ops->get_cpl(vcpu) == 3) access |= PFERR_USER_MASK; - /* - * FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED - * is returned, but our callers are not ready for that and they blindly - * call kvm_inject_page_fault. Ensure that they at least do not leak - * uninitialized kernel stack memory into cr2 and error code. - */ - memset(exception, 0, sizeof(*exception)); return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, access, exception); } @@ -4431,6 +4424,13 @@ static int emulator_write_std(struct x86_emulate_ctxt *ctxt, gva_t addr, void *v int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val, unsigned int bytes, struct x86_exception *exception) { + /* + * FIXME: this should call handle_emulation_failure if X86EMUL_IO_NEEDED + * is returned, but our callers are not ready for that and they blindly + * call kvm_inject_page_fault. Ensure that they at least do not leak + * uninitialized kernel stack memory into cr2 and error code. + */ + memset(exception, 0, sizeof(*exception)); return kvm_write_guest_virt_helper(addr, val, bytes, vcpu, PFERR_WRITE_MASK, exception); } |