2017-12-04 14:26:40

by Jinbum Park

Subject: [kernel-hardening][PATCH v3 2/3] arm: mm: dump: make the page table dumping seq_file optional

This patch makes the page table dumping seq_file optional.
It makes the page table dumping code usable for other cases.

This patch refers below commit of arm64.
(ae5d1cf358a5
("arm64: dump: Make the page table dumping seq_file optional"))

Signed-off-by: Jinbum Park <[email protected]>
---
v3: No changes

arch/arm/mm/dump.c | 28 +++++++++++++++++++++-------
1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
index 8dfe7c3..43a2bee 100644
--- a/arch/arm/mm/dump.c
+++ b/arch/arm/mm/dump.c
@@ -34,6 +34,18 @@
{ -1, NULL },
};

+#define pt_dump_seq_printf(m, fmt, args...) \
+({ \
+ if (m) \
+ seq_printf(m, fmt, ##args); \
+})
+
+#define pt_dump_seq_puts(m, fmt) \
+({ \
+ if (m) \
+ seq_printf(m, fmt); \
+})
+
struct pg_state {
struct seq_file *seq;
const struct addr_marker *marker;
@@ -210,7 +222,7 @@ static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t
s = bits->clear;

if (s)
- seq_printf(st->seq, " %s", s);
+ pt_dump_seq_printf(st->seq, " %s", s);
}
}

@@ -224,7 +236,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
st->level = level;
st->current_prot = prot;
st->current_domain = domain;
- seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
} else if (prot != st->current_prot || level != st->level ||
domain != st->current_domain ||
addr >= st->marker[1].start_address) {
@@ -232,7 +244,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
unsigned long delta;

if (st->current_prot) {
- seq_printf(st->seq, "0x%08lx-0x%08lx ",
+ pt_dump_seq_printf(st->seq, "0x%08lx-0x%08lx ",
st->start_address, addr);

delta = (addr - st->start_address) >> 10;
@@ -240,17 +252,19 @@ static void note_page(struct pg_state *st, unsigned long addr,
delta >>= 10;
unit++;
}
- seq_printf(st->seq, "%9lu%c", delta, *unit);
+ pt_dump_seq_printf(st->seq, "%9lu%c", delta, *unit);
if (st->current_domain)
- seq_printf(st->seq, " %s", st->current_domain);
+ pt_dump_seq_printf(st->seq, " %s",
+ st->current_domain);
if (pg_level[st->level].bits)
dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
- seq_printf(st->seq, "\n");
+ pt_dump_seq_printf(st->seq, "\n");
}

if (addr >= st->marker[1].start_address) {
st->marker++;
- seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
+ st->marker->name);
}
st->start_address = addr;
st->current_prot = prot;
--
1.9.1

2017-12-05 19:53:54

by Kees Cook

Subject: Re: [kernel-hardening][PATCH v3 2/3] arm: mm: dump: make the page table dumping seq_file optional

On Mon, Dec 4, 2017 at 6:26 AM, Jinbum Park <[email protected]> wrote:
> This patch makes the page table dumping seq_file optional.
> It makes the page table dumping code usable for other cases.
>
> This patch refers below commit of arm64.
> (ae5d1cf358a5
> ("arm64: dump: Make the page table dumping seq_file optional"))
>
> Signed-off-by: Jinbum Park <[email protected]>

Looks good to me. :)

Acked-by: Kees Cook <[email protected]>

-Kees

> ---
> v3: No changes
>
> arch/arm/mm/dump.c | 28 +++++++++++++++++++++-------
> 1 file changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
> index 8dfe7c3..43a2bee 100644
> --- a/arch/arm/mm/dump.c
> +++ b/arch/arm/mm/dump.c
> @@ -34,6 +34,18 @@
> { -1, NULL },
> };
>
> +#define pt_dump_seq_printf(m, fmt, args...) \
> +({ \
> + if (m) \
> + seq_printf(m, fmt, ##args); \
> +})
> +
> +#define pt_dump_seq_puts(m, fmt) \
> +({ \
> + if (m) \
> + seq_printf(m, fmt); \
> +})
> +
> struct pg_state {
> struct seq_file *seq;
> const struct addr_marker *marker;
> @@ -210,7 +222,7 @@ static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t
> s = bits->clear;
>
> if (s)
> - seq_printf(st->seq, " %s", s);
> + pt_dump_seq_printf(st->seq, " %s", s);
> }
> }
>
> @@ -224,7 +236,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
> st->level = level;
> st->current_prot = prot;
> st->current_domain = domain;
> - seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
> + pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
> } else if (prot != st->current_prot || level != st->level ||
> domain != st->current_domain ||
> addr >= st->marker[1].start_address) {
> @@ -232,7 +244,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
> unsigned long delta;
>
> if (st->current_prot) {
> - seq_printf(st->seq, "0x%08lx-0x%08lx ",
> + pt_dump_seq_printf(st->seq, "0x%08lx-0x%08lx ",
> st->start_address, addr);
>
> delta = (addr - st->start_address) >> 10;
> @@ -240,17 +252,19 @@ static void note_page(struct pg_state *st, unsigned long addr,
> delta >>= 10;
> unit++;
> }
> - seq_printf(st->seq, "%9lu%c", delta, *unit);
> + pt_dump_seq_printf(st->seq, "%9lu%c", delta, *unit);
> if (st->current_domain)
> - seq_printf(st->seq, " %s", st->current_domain);
> + pt_dump_seq_printf(st->seq, " %s",
> + st->current_domain);
> if (pg_level[st->level].bits)
> dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
> - seq_printf(st->seq, "\n");
> + pt_dump_seq_printf(st->seq, "\n");
> }
>
> if (addr >= st->marker[1].start_address) {
> st->marker++;
> - seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
> + pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
> + st->marker->name);
> }
> st->start_address = addr;
> st->current_prot = prot;
> --
> 1.9.1
>



--
Kees Cook
Pixel Security