| Message ID | 20230717181732.84039-1-haitao.huang@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/sgx: fix a NULL pointer | expand |
On Mon Jul 17, 2023 at 6:17 PM UTC, Haitao Huang wrote: > Under heavy load, the SGX EPC reclaimers (current ksgxd or future EPC > cgroup worker) may reclaim the SECS EPC page for an enclave and set > encl->secs.epc_page to NULL. But the SECS EPC page is used for EAUG in > the SGX #PF handler without checking for NULL and reloading. > > Fix this by checking if SECS is loaded before EAUG and load it if it was > reclaimed. > > Fixes: 5a90d2c3f5ef8 ("x86/sgx: Support adding of pages to an initialized enclave") > Cc: stable@vger.kernel.org > Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com> > --- > arch/x86/kernel/cpu/sgx/encl.c | 25 ++++++++++++++++++++----- > arch/x86/kernel/cpu/sgx/main.c | 4 ++++ > 2 files changed, 24 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index 2a0e90fe2abc..d39e502bb7b0 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -235,6 +235,16 @@ static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page, > return epc_page; > } > > +static struct sgx_epc_page *sgx_encl_load_secs(struct sgx_encl *encl) > +{ > + struct sgx_epc_page *epc_page = encl->secs.epc_page; > + > + if (!epc_page) { > + epc_page = sgx_encl_eldu(&encl->secs, NULL); > + } remove curly braces > + return epc_page; > +} > + > static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, > struct sgx_encl_page *entry) > { > @@ -248,11 +258,9 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, > return entry; > } > > - if (!(encl->secs.epc_page)) { > - epc_page = sgx_encl_eldu(&encl->secs, NULL); > - if (IS_ERR(epc_page)) > - return ERR_CAST(epc_page); > - } > + epc_page = sgx_encl_load_secs(encl); > + if (IS_ERR(epc_page)) > + return ERR_CAST(epc_page); > > epc_page = sgx_encl_eldu(entry, encl->secs.epc_page); > if (IS_ERR(epc_page)) > @@ -339,6 +347,13 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma, > > mutex_lock(&encl->lock); > > + epc_page = sgx_encl_load_secs(encl); > + if (IS_ERR(epc_page)) { > + if (PTR_ERR(epc_page) == -EBUSY) > + vmret = VM_FAULT_NOPAGE; > + goto err_out_unlock; > + } > + > epc_page = sgx_alloc_epc_page(encl_page, false); > if (IS_ERR(epc_page)) { > if (PTR_ERR(epc_page) == -EBUSY) > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > index 166692f2d501..4662a364ce62 100644 > --- a/arch/x86/kernel/cpu/sgx/main.c > +++ b/arch/x86/kernel/cpu/sgx/main.c > @@ -257,6 +257,10 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, > > mutex_lock(&encl->lock); > > + /* Should not be possible */ > + if (WARN_ON(!(encl->secs.epc_page))) > + goto out; > + > sgx_encl_ewb(epc_page, backing); > encl_page->epc_page = NULL; > encl->secs_child_cnt--; > -- > 2.25.1 BR, Jarkko
On Mon Jul 17, 2023 at 6:53 PM UTC, Jarkko Sakkinen wrote: > On Mon Jul 17, 2023 at 6:17 PM UTC, Haitao Huang wrote: > > +static struct sgx_epc_page *sgx_encl_load_secs(struct sgx_encl *encl) > > +{ > > + struct sgx_epc_page *epc_page = encl->secs.epc_page; > > + > > + if (!epc_page) { > > + epc_page = sgx_encl_eldu(&encl->secs, NULL); > > + } > > remove curly braces And add an empty line before the return statement. BR, Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 2a0e90fe2abc..d39e502bb7b0 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -235,6 +235,16 @@ static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page, return epc_page; } +static struct sgx_epc_page *sgx_encl_load_secs(struct sgx_encl *encl) +{ + struct sgx_epc_page *epc_page = encl->secs.epc_page; + + if (!epc_page) { + epc_page = sgx_encl_eldu(&encl->secs, NULL); + } + return epc_page; +} + static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, struct sgx_encl_page *entry) { @@ -248,11 +258,9 @@ static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, return entry; } - if (!(encl->secs.epc_page)) { - epc_page = sgx_encl_eldu(&encl->secs, NULL); - if (IS_ERR(epc_page)) - return ERR_CAST(epc_page); - } + epc_page = sgx_encl_load_secs(encl); + if (IS_ERR(epc_page)) + return ERR_CAST(epc_page); epc_page = sgx_encl_eldu(entry, encl->secs.epc_page); if (IS_ERR(epc_page)) @@ -339,6 +347,13 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma, mutex_lock(&encl->lock); + epc_page = sgx_encl_load_secs(encl); + if (IS_ERR(epc_page)) { + if (PTR_ERR(epc_page) == -EBUSY) + vmret = VM_FAULT_NOPAGE; + goto err_out_unlock; + } + epc_page = sgx_alloc_epc_page(encl_page, false); if (IS_ERR(epc_page)) { if (PTR_ERR(epc_page) == -EBUSY) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 166692f2d501..4662a364ce62 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -257,6 +257,10 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page, mutex_lock(&encl->lock); + /* Should not be possible */ + if (WARN_ON(!(encl->secs.epc_page))) + goto out; + sgx_encl_ewb(epc_page, backing); encl_page->epc_page = NULL; encl->secs_child_cnt--;
Under heavy load, the SGX EPC reclaimers (current ksgxd or future EPC cgroup worker) may reclaim the SECS EPC page for an enclave and set encl->secs.epc_page to NULL. But the SECS EPC page is used for EAUG in the SGX #PF handler without checking for NULL and reloading. Fix this by checking if SECS is loaded before EAUG and load it if it was reclaimed. Fixes: 5a90d2c3f5ef8 ("x86/sgx: Support adding of pages to an initialized enclave") Cc: stable@vger.kernel.org Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 25 ++++++++++++++++++++----- arch/x86/kernel/cpu/sgx/main.c | 4 ++++ 2 files changed, 24 insertions(+), 5 deletions(-)