| Message ID | 20201005004120.105849-1-jarkko.sakkinen@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/sgx: Fix sgx_encl_may_map locking | expand |
On Sun, 04 Oct 2020 19:41:20 -0500, Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> wrote: > Fix the issue further discussed in: > > 1. > https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@mqcpg7oapc828.gar.corp.intel.com/ > 2. > https://lore.kernel.org/linux-sgx/20201003195440.GD20115@casper.infradead.org/ > > Reported-by: Haitao Huang <haitao.huang@linux.intel.com> > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > Cc: Jethro Beekman <jethro@fortanix.com> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > --- > arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c > b/arch/x86/kernel/cpu/sgx/encl.c > index ae45f8f0951e..a225e96c7a39 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -304,11 +304,10 @@ int sgx_encl_may_map(struct sgx_encl *encl, > unsigned long start, > unsigned long end, unsigned long vm_flags) > { > unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC); > - unsigned long idx_start = PFN_DOWN(start); > - unsigned long idx_end = PFN_DOWN(end - 1); > + unsigned long start_i = PFN_DOWN(start); > + unsigned long end_i = PFN_DOWN(end - 1); > struct sgx_encl_page *page; > - > - XA_STATE(xas, &encl->page_array, idx_start); > + int i; > /* > * Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might > @@ -317,9 +316,14 @@ int sgx_encl_may_map(struct sgx_encl *encl, > unsigned long start, > if (current->personality & READ_IMPLIES_EXEC) > return -EACCES; > - xas_for_each(&xas, page, idx_end) > + for (i = start_i; i <= end_i; i++) { > + mutex_lock(&encl->lock); > + page = xa_load(&encl->page_array, i); > + mutex_unlock(&encl->lock); > + > if (!page || (~page->vm_max_prot_bits & vm_prot_bits)) > return -EACCES; > + } > return 0; > } Works with no PROVE_LOCKING complaints. Haitao
On Sun, Oct 04, 2020 at 10:27:43PM -0500, Haitao Huang wrote: > On Sun, 04 Oct 2020 19:41:20 -0500, Jarkko Sakkinen > <jarkko.sakkinen@linux.intel.com> wrote: > > > Fix the issue further discussed in: > > > > 1. https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@mqcpg7oapc828.gar.corp.intel.com/ > > 2. https://lore.kernel.org/linux-sgx/20201003195440.GD20115@casper.infradead.org/ > > > > Reported-by: Haitao Huang <haitao.huang@linux.intel.com> > > Cc: Sean Christopherson <sean.j.christopherson@intel.com> > > Cc: Jethro Beekman <jethro@fortanix.com> > > Cc: Matthew Wilcox <willy@infradead.org> > > Cc: Dave Hansen <dave.hansen@linux.intel.com> > > Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> > > --- > > arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++++----- > > 1 file changed, 9 insertions(+), 5 deletions(-) > > > > diff --git a/arch/x86/kernel/cpu/sgx/encl.c > > b/arch/x86/kernel/cpu/sgx/encl.c > > index ae45f8f0951e..a225e96c7a39 100644 > > --- a/arch/x86/kernel/cpu/sgx/encl.c > > +++ b/arch/x86/kernel/cpu/sgx/encl.c > > @@ -304,11 +304,10 @@ int sgx_encl_may_map(struct sgx_encl *encl, > > unsigned long start, > > unsigned long end, unsigned long vm_flags) > > { > > unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC); > > - unsigned long idx_start = PFN_DOWN(start); > > - unsigned long idx_end = PFN_DOWN(end - 1); > > + unsigned long start_i = PFN_DOWN(start); > > + unsigned long end_i = PFN_DOWN(end - 1); > > struct sgx_encl_page *page; > > - > > - XA_STATE(xas, &encl->page_array, idx_start); > > + int i; > > /* > > * Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might > > @@ -317,9 +316,14 @@ int sgx_encl_may_map(struct sgx_encl *encl, > > unsigned long start, > > if (current->personality & READ_IMPLIES_EXEC) > > return -EACCES; > > - xas_for_each(&xas, page, idx_end) > > + for (i = start_i; i <= end_i; i++) { > > + mutex_lock(&encl->lock); > > + page = xa_load(&encl->page_array, i); > > + mutex_unlock(&encl->lock); > > + > > if (!page || (~page->vm_max_prot_bits & vm_prot_bits)) > > return -EACCES; > > + } > > return 0; > > } > > Works with no PROVE_LOCKING complaints. > Haitao Great. That is a good reference point. Thank you. v2 should work too but needs to be checked. /Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index ae45f8f0951e..a225e96c7a39 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -304,11 +304,10 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, unsigned long end, unsigned long vm_flags) { unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC); - unsigned long idx_start = PFN_DOWN(start); - unsigned long idx_end = PFN_DOWN(end - 1); + unsigned long start_i = PFN_DOWN(start); + unsigned long end_i = PFN_DOWN(end - 1); struct sgx_encl_page *page; - - XA_STATE(xas, &encl->page_array, idx_start); + int i; /* * Disallow READ_IMPLIES_EXEC tasks as their VMA permissions might @@ -317,9 +316,14 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start, if (current->personality & READ_IMPLIES_EXEC) return -EACCES; - xas_for_each(&xas, page, idx_end) + for (i = start_i; i <= end_i; i++) { + mutex_lock(&encl->lock); + page = xa_load(&encl->page_array, i); + mutex_unlock(&encl->lock); + if (!page || (~page->vm_max_prot_bits & vm_prot_bits)) return -EACCES; + } return 0; }
Fix the issue further discussed in: 1. https://lore.kernel.org/linux-sgx/op.0rwbv916wjvjmi@mqcpg7oapc828.gar.corp.intel.com/ 2. https://lore.kernel.org/linux-sgx/20201003195440.GD20115@casper.infradead.org/ Reported-by: Haitao Huang <haitao.huang@linux.intel.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Jethro Beekman <jethro@fortanix.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)