| Message ID | 20190128141251.28094-1-juergh@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [SRU,Bionic] x86/mm: Do not warn about PCI BIOS W+X mappings | expand |
This is for Cosmic, not Bionic. ...Juerg > From: Thomas Gleixner <tglx@linutronix.de> > > BugLink: https://bugs.launchpad.net/bugs/1813532 > > PCI BIOS requires the BIOS area 0x0A0000-0x0FFFFFF to be mapped W+X for > various legacy reasons. When CONFIG_DEBUG_WX is enabled, this triggers the > WX warning, but this is misleading because the mapping is required and is > not a result of an accidental oversight. > > Prevent the full warning when PCI BIOS is enabled and the detected WX > mapping is in the BIOS area. Just emit a pr_warn() which denotes the > fact. This is partially duplicating the info which the PCI BIOS code emits > when it maps the area as executable, but that info is not in the context of > the WX checking output. > > Remove the extra %p printout in the WARN_ONCE() while at it. %pS is enough. > > Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Tested-by: Borislav Petkov <bp@suse.de> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1810082151160.2455@nanos.tec.linutronix.de > > (cherry picked from commit c200dac78fec66d87ef262cac38cfe4feabdf737) > Signed-off-by: Juerg Haefliger <juergh@canonical.com> > --- > arch/x86/mm/dump_pagetables.c | 35 +++++++++++++++++++++++++++-------- > 1 file changed, 27 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c > index 2f3c9196b834..587196cec335 100644 > --- a/arch/x86/mm/dump_pagetables.c > +++ b/arch/x86/mm/dump_pagetables.c > @@ -19,7 +19,9 @@ > #include <linux/sched.h> > #include <linux/seq_file.h> > #include <linux/highmem.h> > +#include <linux/pci.h> > > +#include <asm/e820/types.h> > #include <asm/pgtable.h> > > /* > @@ -231,6 +233,29 @@ static unsigned long normalize_addr(unsigned long u) > return (signed long)(u << shift) >> shift; > } > > +static void note_wx(struct pg_state *st) > +{ > + unsigned long npages; > + > + npages = (st->current_address - st->start_address) / PAGE_SIZE; > + > +#ifdef CONFIG_PCI_BIOS > + /* > + * If PCI BIOS is enabled, the PCI BIOS area is forced to WX. > + * Inform about it, but avoid the warning. > + */ > + if (pcibios_enabled && st->start_address >= PAGE_OFFSET + BIOS_BEGIN && > + st->current_address <= PAGE_OFFSET + BIOS_END) { > + pr_warn_once("x86/mm: PCI BIOS W+X mapping %lu pages\n", npages); > + return; > + } > +#endif > + /* Account the WX pages */ > + st->wx_pages += npages; > + WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n", > + (void *)st->start_address); > +} > + > /* > * This function gets called on a break in a continuous series > * of PTE entries; the next one is different so we need to > @@ -266,14 +291,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, > unsigned long delta; > int width = sizeof(unsigned long) * 2; > > - if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) { > - WARN_ONCE(1, > - "x86/mm: Found insecure W+X mapping at address %p/%pS\n", > - (void *)st->start_address, > - (void *)st->start_address); > - st->wx_pages += (st->current_address - > - st->start_address) / PAGE_SIZE; > - } > + if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) > + note_wx(st); > > /* > * Now print the actual finished series
On 28.01.19 15:12, Juerg Haefliger wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > BugLink: https://bugs.launchpad.net/bugs/1813532 > > PCI BIOS requires the BIOS area 0x0A0000-0x0FFFFFF to be mapped W+X for > various legacy reasons. When CONFIG_DEBUG_WX is enabled, this triggers the > WX warning, but this is misleading because the mapping is required and is > not a result of an accidental oversight. > > Prevent the full warning when PCI BIOS is enabled and the detected WX > mapping is in the BIOS area. Just emit a pr_warn() which denotes the > fact. This is partially duplicating the info which the PCI BIOS code emits > when it maps the area as executable, but that info is not in the context of > the WX checking output. > > Remove the extra %p printout in the WARN_ONCE() while at it. %pS is enough. > > Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Tested-by: Borislav Petkov <bp@suse.de> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1810082151160.2455@nanos.tec.linutronix.de > > (cherry picked from commit c200dac78fec66d87ef262cac38cfe4feabdf737) > Signed-off-by: Juerg Haefliger <juergh@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> > --- Noting the adjusted destination series. > arch/x86/mm/dump_pagetables.c | 35 +++++++++++++++++++++++++++-------- > 1 file changed, 27 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c > index 2f3c9196b834..587196cec335 100644 > --- a/arch/x86/mm/dump_pagetables.c > +++ b/arch/x86/mm/dump_pagetables.c > @@ -19,7 +19,9 @@ > #include <linux/sched.h> > #include <linux/seq_file.h> > #include <linux/highmem.h> > +#include <linux/pci.h> > > +#include <asm/e820/types.h> > #include <asm/pgtable.h> > > /* > @@ -231,6 +233,29 @@ static unsigned long normalize_addr(unsigned long u) > return (signed long)(u << shift) >> shift; > } > > +static void note_wx(struct pg_state *st) > +{ > + unsigned long npages; > + > + npages = (st->current_address - st->start_address) / PAGE_SIZE; > + > +#ifdef CONFIG_PCI_BIOS > + /* > + * If PCI BIOS is enabled, the PCI BIOS area is forced to WX. > + * Inform about it, but avoid the warning. > + */ > + if (pcibios_enabled && st->start_address >= PAGE_OFFSET + BIOS_BEGIN && > + st->current_address <= PAGE_OFFSET + BIOS_END) { > + pr_warn_once("x86/mm: PCI BIOS W+X mapping %lu pages\n", npages); > + return; > + } > +#endif > + /* Account the WX pages */ > + st->wx_pages += npages; > + WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n", > + (void *)st->start_address); > +} > + > /* > * This function gets called on a break in a continuous series > * of PTE entries; the next one is different so we need to > @@ -266,14 +291,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, > unsigned long delta; > int width = sizeof(unsigned long) * 2; > > - if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) { > - WARN_ONCE(1, > - "x86/mm: Found insecure W+X mapping at address %p/%pS\n", > - (void *)st->start_address, > - (void *)st->start_address); > - st->wx_pages += (st->current_address - > - st->start_address) / PAGE_SIZE; > - } > + if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) > + note_wx(st); > > /* > * Now print the actual finished series >
On 1/28/19 3:12 PM, Juerg Haefliger wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > BugLink: https://bugs.launchpad.net/bugs/1813532 > > PCI BIOS requires the BIOS area 0x0A0000-0x0FFFFFF to be mapped W+X for > various legacy reasons. When CONFIG_DEBUG_WX is enabled, this triggers the > WX warning, but this is misleading because the mapping is required and is > not a result of an accidental oversight. > > Prevent the full warning when PCI BIOS is enabled and the detected WX > mapping is in the BIOS area. Just emit a pr_warn() which denotes the > fact. This is partially duplicating the info which the PCI BIOS code emits > when it maps the area as executable, but that info is not in the context of > the WX checking output. > > Remove the extra %p printout in the WARN_ONCE() while at it. %pS is enough. > > Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Tested-by: Borislav Petkov <bp@suse.de> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1810082151160.2455@nanos.tec.linutronix.de > > (cherry picked from commit c200dac78fec66d87ef262cac38cfe4feabdf737) > Signed-off-by: Juerg Haefliger <juergh@canonical.com> For *Cosmic*: Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> > --- > arch/x86/mm/dump_pagetables.c | 35 +++++++++++++++++++++++++++-------- > 1 file changed, 27 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c > index 2f3c9196b834..587196cec335 100644 > --- a/arch/x86/mm/dump_pagetables.c > +++ b/arch/x86/mm/dump_pagetables.c > @@ -19,7 +19,9 @@ > #include <linux/sched.h> > #include <linux/seq_file.h> > #include <linux/highmem.h> > +#include <linux/pci.h> > > +#include <asm/e820/types.h> > #include <asm/pgtable.h> > > /* > @@ -231,6 +233,29 @@ static unsigned long normalize_addr(unsigned long u) > return (signed long)(u << shift) >> shift; > } > > +static void note_wx(struct pg_state *st) > +{ > + unsigned long npages; > + > + npages = (st->current_address - st->start_address) / PAGE_SIZE; > + > +#ifdef CONFIG_PCI_BIOS > + /* > + * If PCI BIOS is enabled, the PCI BIOS area is forced to WX. > + * Inform about it, but avoid the warning. > + */ > + if (pcibios_enabled && st->start_address >= PAGE_OFFSET + BIOS_BEGIN && > + st->current_address <= PAGE_OFFSET + BIOS_END) { > + pr_warn_once("x86/mm: PCI BIOS W+X mapping %lu pages\n", npages); > + return; > + } > +#endif > + /* Account the WX pages */ > + st->wx_pages += npages; > + WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n", > + (void *)st->start_address); > +} > + > /* > * This function gets called on a break in a continuous series > * of PTE entries; the next one is different so we need to > @@ -266,14 +291,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, > unsigned long delta; > int width = sizeof(unsigned long) * 2; > > - if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) { > - WARN_ONCE(1, > - "x86/mm: Found insecure W+X mapping at address %p/%pS\n", > - (void *)st->start_address, > - (void *)st->start_address); > - st->wx_pages += (st->current_address - > - st->start_address) / PAGE_SIZE; > - } > + if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) > + note_wx(st); > > /* > * Now print the actual finished series
On 28.01.19 15:12, Juerg Haefliger wrote: > From: Thomas Gleixner <tglx@linutronix.de> > > BugLink: https://bugs.launchpad.net/bugs/1813532 > > PCI BIOS requires the BIOS area 0x0A0000-0x0FFFFFF to be mapped W+X for > various legacy reasons. When CONFIG_DEBUG_WX is enabled, this triggers the > WX warning, but this is misleading because the mapping is required and is > not a result of an accidental oversight. > > Prevent the full warning when PCI BIOS is enabled and the detected WX > mapping is in the BIOS area. Just emit a pr_warn() which denotes the > fact. This is partially duplicating the info which the PCI BIOS code emits > when it maps the area as executable, but that info is not in the context of > the WX checking output. > > Remove the extra %p printout in the WARN_ONCE() while at it. %pS is enough. > > Reported-by: Paul Menzel <pmenzel@molgen.mpg.de> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Tested-by: Borislav Petkov <bp@suse.de> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Kees Cook <keescook@chromium.org> > Cc: Bjorn Helgaas <bhelgaas@google.com> > Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1810082151160.2455@nanos.tec.linutronix.de > > (cherry picked from commit c200dac78fec66d87ef262cac38cfe4feabdf737) > Signed-off-by: Juerg Haefliger <juergh@canonical.com> > --- Actually was already applied together with those ACKs when the Bionic submission was done. I checked whether this Cosmic version would cleanly reverse apply and it did. Applied to cosmic/master-next. Thanks. -Stefan > arch/x86/mm/dump_pagetables.c | 35 +++++++++++++++++++++++++++-------- > 1 file changed, 27 insertions(+), 8 deletions(-) > > diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c > index 2f3c9196b834..587196cec335 100644 > --- a/arch/x86/mm/dump_pagetables.c > +++ b/arch/x86/mm/dump_pagetables.c > @@ -19,7 +19,9 @@ > #include <linux/sched.h> > #include <linux/seq_file.h> > #include <linux/highmem.h> > +#include <linux/pci.h> > > +#include <asm/e820/types.h> > #include <asm/pgtable.h> > > /* > @@ -231,6 +233,29 @@ static unsigned long normalize_addr(unsigned long u) > return (signed long)(u << shift) >> shift; > } > > +static void note_wx(struct pg_state *st) > +{ > + unsigned long npages; > + > + npages = (st->current_address - st->start_address) / PAGE_SIZE; > + > +#ifdef CONFIG_PCI_BIOS > + /* > + * If PCI BIOS is enabled, the PCI BIOS area is forced to WX. > + * Inform about it, but avoid the warning. > + */ > + if (pcibios_enabled && st->start_address >= PAGE_OFFSET + BIOS_BEGIN && > + st->current_address <= PAGE_OFFSET + BIOS_END) { > + pr_warn_once("x86/mm: PCI BIOS W+X mapping %lu pages\n", npages); > + return; > + } > +#endif > + /* Account the WX pages */ > + st->wx_pages += npages; > + WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n", > + (void *)st->start_address); > +} > + > /* > * This function gets called on a break in a continuous series > * of PTE entries; the next one is different so we need to > @@ -266,14 +291,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, > unsigned long delta; > int width = sizeof(unsigned long) * 2; > > - if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) { > - WARN_ONCE(1, > - "x86/mm: Found insecure W+X mapping at address %p/%pS\n", > - (void *)st->start_address, > - (void *)st->start_address); > - st->wx_pages += (st->current_address - > - st->start_address) / PAGE_SIZE; > - } > + if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) > + note_wx(st); > > /* > * Now print the actual finished series >
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 2f3c9196b834..587196cec335 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -19,7 +19,9 @@ #include <linux/sched.h> #include <linux/seq_file.h> #include <linux/highmem.h> +#include <linux/pci.h> +#include <asm/e820/types.h> #include <asm/pgtable.h> /* @@ -231,6 +233,29 @@ static unsigned long normalize_addr(unsigned long u) return (signed long)(u << shift) >> shift; } +static void note_wx(struct pg_state *st) +{ + unsigned long npages; + + npages = (st->current_address - st->start_address) / PAGE_SIZE; + +#ifdef CONFIG_PCI_BIOS + /* + * If PCI BIOS is enabled, the PCI BIOS area is forced to WX. + * Inform about it, but avoid the warning. + */ + if (pcibios_enabled && st->start_address >= PAGE_OFFSET + BIOS_BEGIN && + st->current_address <= PAGE_OFFSET + BIOS_END) { + pr_warn_once("x86/mm: PCI BIOS W+X mapping %lu pages\n", npages); + return; + } +#endif + /* Account the WX pages */ + st->wx_pages += npages; + WARN_ONCE(1, "x86/mm: Found insecure W+X mapping at address %pS\n", + (void *)st->start_address); +} + /* * This function gets called on a break in a continuous series * of PTE entries; the next one is different so we need to @@ -266,14 +291,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, unsigned long delta; int width = sizeof(unsigned long) * 2; - if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) { - WARN_ONCE(1, - "x86/mm: Found insecure W+X mapping at address %p/%pS\n", - (void *)st->start_address, - (void *)st->start_address); - st->wx_pages += (st->current_address - - st->start_address) / PAGE_SIZE; - } + if (st->check_wx && (eff & _PAGE_RW) && !(eff & _PAGE_NX)) + note_wx(st); /* * Now print the actual finished series