2010-12-25 09:57:16

by Ahmed S. Darwish

Subject: [PATCH, Bugfix] RAMOOPS: Don't overflow over non-allocated regions

Hi,

Current code mis-calculates the ramoops header size, leading to an
overflow over the next record at best, or over a non-allocated region
at worst. Fix that calculation.

Signed-off-by: Ahmed S. Darwish <[email protected]>
--

Shouldn't this be added to -stable too?

Happy New Year!

drivers/char/ramoops.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c
index 73dcb0e..d3d63be 100644
--- a/drivers/char/ramoops.c
+++ b/drivers/char/ramoops.c
@@ -29,7 +29,6 @@
#include <linux/ramoops.h>

#define RAMOOPS_KERNMSG_HDR "===="
-#define RAMOOPS_HEADER_SIZE (5 + sizeof(struct timeval))

#define RECORD_SIZE 4096

@@ -65,8 +64,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
struct ramoops_context, dump);
unsigned long s1_start, s2_start;
unsigned long l1_cpy, l2_cpy;
- int res;
- char *buf;
+ int res, hdr_size;
+ char *buf, *buf_orig;
struct timeval timestamp;

/* Only dump oopses if dump_oops is set */
@@ -74,6 +73,8 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
return;

buf = (char *)(cxt->virt_addr + (cxt->count * RECORD_SIZE));
+ buf_orig = buf;
+
memset(buf, '\0', RECORD_SIZE);
res = sprintf(buf, "%s", RAMOOPS_KERNMSG_HDR);
buf += res;
@@ -81,8 +82,9 @@ static void ramoops_do_dump(struct kmsg_dumper *dumper,
res = sprintf(buf, "%lu.%lu\n", (long)timestamp.tv_sec, (long)timestamp.tv_usec);
buf += res;

- l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE));
- l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - RAMOOPS_HEADER_SIZE) - l2_cpy);
+ hdr_size = buf - buf_orig;
+ l2_cpy = min(l2, (unsigned long)(RECORD_SIZE - hdr_size));
+ l1_cpy = min(l1, (unsigned long)(RECORD_SIZE - hdr_size) - l2_cpy);

s2_start = l2 - l2_cpy;
s1_start = l1 - l1_cpy;

--
Darwish
http://darwish.07.googlepages.com

2010-12-25 11:23:17

by Marco Stornelli

Subject: Re: [PATCH, Bugfix] RAMOOPS: Don't overflow over non-allocated regions

Il 25/12/2010 10:57, Ahmed S. Darwish ha scritto:
> Hi,
>
> Current code mis-calculates the ramoops header size, leading to an
> overflow over the next record at best, or over a non-allocated region
> at worst. Fix that calculation.
>
> Signed-off-by: Ahmed S. Darwish <[email protected]>
> --

Acked-by: Marco Stornelli <[email protected]>

2010-12-27 21:33:22

by Ahmed S. Darwish

Subject: Re: [PATCH, Bugfix] RAMOOPS: Don't overflow over non-allocated regions

On Sat, Dec 25, 2010 at 12:19:35PM +0100, Marco Stornelli wrote:
> Il 25/12/2010 10:57, Ahmed S. Darwish ha scritto:
> >
> > Current code mis-calculates the ramoops header size, leading to an
> > overflow over the next record at best, or over a non-allocated region
> > at worst. Fix that calculation.
> >
> > Signed-off-by: Ahmed S. Darwish <[email protected]>
> > --
>
> Acked-by: Marco Stornelli <[email protected]>
>

Someone to push this to Linus before -rc8? Andrew?

--
Darwish
http://darwish.07.googlepages.com