On Tue, Jul 21, 2015 at 11:11 AM, Naoya Horiguchi <[email protected]> wrote: > On Tue, Jul 14, 2015 at 06:37:47PM +0300, Konstantin Khlebnikov wrote: >> This patch makes pagemap readable for normal users and hides physical >> addresses from them. For some use-cases PFN isn't required at all. >> >> Signed-off-by: Konstantin Khlebnikov <[email protected]> >> Fixes: ab676b7d6fbf ("pagemap: do not leak physical addresses to >> non-privileged userspace") >> Link: >> http://lkml.kernel.org/r/[email protected] >> --- >> fs/proc/task_mmu.c | 25 ++++++++++++++----------- >> 1 file changed, 14 insertions(+), 11 deletions(-) >> >> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c >> index 040721fa405a..3a5d338ea219 100644 >> --- a/fs/proc/task_mmu.c >> +++ b/fs/proc/task_mmu.c >> @@ -937,6 +937,7 @@ typedef struct { >> struct pagemapread { >> int pos, len; /* units: PM_ENTRY_BYTES, not bytes */ >> pagemap_entry_t *buffer; >> + bool show_pfn; >> }; >> >> #define PAGEMAP_WALK_SIZE (PMD_SIZE) >> @@ -1013,7 +1014,8 @@ static pagemap_entry_t pte_to_pagemap_entry(struct >> pagemapread *pm, >> struct page *page = NULL; >> >> if (pte_present(pte)) { >> - frame = pte_pfn(pte); >> + if (pm->show_pfn) >> + frame = pte_pfn(pte); >> flags |= PM_PRESENT; >> page = vm_normal_page(vma, addr, pte); >> if (pte_soft_dirty(pte)) > > Don't you need the same if (pm->show_pfn) check in is_swap_pte path, too? > (although I don't think that it can be exploited by row hammer attack ...)
Yeah, but I see no reason for that. Probably except swap on ramdrive, but this too weird =) > > Thanks, > Naoya Horiguchi > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to [email protected]. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a hrefmailto:"[email protected]";> [email protected] </a> -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
