Messages in this thread |  | | Subject | Re: [PATCH 1/2] /proc/kcore: Fix SMAP violation when dumping vsyscall user page | From | Jia Zhang <> | Date | Mon, 5 Feb 2018 09:32:12 +0800 |
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Hi Jiri,
The maintainers are too busy to review this patchset. You are the author of the commit df04abfd181a. Please help to review this patchset.
Thanks, Jia
On 2018/1/30 下午2:42, Jia Zhang wrote: > The commit df04abfd181a > ("fs/proc/kcore.c: Add bounce buffer for ktext data") introduces a > bounce buffer to work around CONFIG_HARDENED_USERCOPY=y. However, > accessing vsyscall user page will cause SMAP violation in this way. > > In order to fix this issue, simply replace memcpy() with copy_from_user() > may work, but using a common way to handle this sort of user page may be > useful for future. > > Currently, only vsyscall page requires KCORE_USER. > > Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com> > --- > arch/x86/mm/init_64.c | 2 +- > fs/proc/kcore.c | 4 ++++ > include/linux/kcore.h | 1 + > 3 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 4a83728..dab78f6 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -1187,7 +1187,7 @@ void __init mem_init(void) > > /* Register memory areas for /proc/kcore */ > kclist_add(&kcore_vsyscall, (void *)VSYSCALL_ADDR, > - PAGE_SIZE, KCORE_OTHER); > + PAGE_SIZE, KCORE_USER); > > mem_init_print_info(NULL); > } > diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c > index 4bc85cb..e4b0204 100644 > --- a/fs/proc/kcore.c > +++ b/fs/proc/kcore.c > @@ -510,6 +510,10 @@ static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) > /* we have to zero-fill user buffer even if no read */ > if (copy_to_user(buffer, buf, tsz)) > return -EFAULT; > + } else if (m->type == KCORE_USER) { > + /* user page is handled prior to normal kernel page */ > + if (copy_to_user(buffer, (char *)start, tsz)) > + return -EFAULT; > } else { > if (kern_addr_valid(start)) { > unsigned long n; > diff --git a/include/linux/kcore.h b/include/linux/kcore.h > index 7ff25a8..80db19d 100644 > --- a/include/linux/kcore.h > +++ b/include/linux/kcore.h > @@ -10,6 +10,7 @@ enum kcore_type { > KCORE_VMALLOC, > KCORE_RAM, > KCORE_VMEMMAP, > + KCORE_USER, > KCORE_OTHER, > }; > >
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