* [PATCH] ppp_mppe: Don't put InterimKey on the stack
@ 2007-09-21 14:08 Michal Schmidt
2007-09-21 14:40 ` Matt Domsch
0 siblings, 1 reply; 3+ messages in thread
From: Michal Schmidt @ 2007-09-21 14:08 UTC (permalink / raw)
To: Linux Kernel list; +Cc: Frank Cusack, Matt Domsch, linux-ppp
Hello,
The interrupt stack can be in the __START_KERNEL_map region in which
virt_to_page will not work. This caused ppp_mppe to crash on CentOS 5 on x86_64
(http://bugs.centos.org/view.php?id 76).
The fix is to avoid copying the interim key. We can simply use it in its
original place, which is kmalloc'd.
Michal
---
drivers/net/ppp_mppe.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ppp_mppe.c b/drivers/net/ppp_mppe.c
index f79cf87..c0b6d19 100644
--- a/drivers/net/ppp_mppe.c
+++ b/drivers/net/ppp_mppe.c
@@ -136,7 +136,7 @@ struct ppp_mppe_state {
* Key Derivation, from RFC 3078, RFC 3079.
* Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
*/
-static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *InterimKey)
+static void get_new_key_from_sha(struct ppp_mppe_state * state)
{
struct hash_desc desc;
struct scatterlist sg[4];
@@ -153,8 +153,6 @@ static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *I
desc.flags = 0;
crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
-
- memcpy(InterimKey, state->sha1_digest, state->keylen);
}
/*
@@ -163,21 +161,21 @@ static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *I
*/
static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
{
- unsigned char InterimKey[MPPE_MAX_KEY_LEN];
struct scatterlist sg_in[1], sg_out[1];
struct blkcipher_desc desc = { .tfm = state->arc4 };
- get_new_key_from_sha(state, InterimKey);
+ get_new_key_from_sha(state);
if (!initial_key) {
- crypto_blkcipher_setkey(state->arc4, InterimKey, state->keylen);
- setup_sg(sg_in, InterimKey, state->keylen);
+ crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
+ state->keylen);
+ setup_sg(sg_in, state->sha1_digest, state->keylen);
setup_sg(sg_out, state->session_key, state->keylen);
if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
state->keylen) != 0) {
printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
}
} else {
- memcpy(state->session_key, InterimKey, state->keylen);
+ memcpy(state->session_key, state->sha1_digest, state->keylen);
}
if (state->keylen = 8) {
/* See RFC 3078 */
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] ppp_mppe: Don't put InterimKey on the stack
2007-09-21 14:08 [PATCH] ppp_mppe: Don't put InterimKey on the stack Michal Schmidt
@ 2007-09-21 14:40 ` Matt Domsch
2007-09-21 14:47 ` Michal Schmidt
0 siblings, 1 reply; 3+ messages in thread
From: Matt Domsch @ 2007-09-21 14:40 UTC (permalink / raw)
To: Michal Schmidt; +Cc: Linux Kernel list, Frank Cusack, linux-ppp
On Fri, Sep 21, 2007 at 04:08:09PM +0200, Michal Schmidt wrote:
> Hello,
>
> The interrupt stack can be in the __START_KERNEL_map region in which
> virt_to_page will not work. This caused ppp_mppe to crash on CentOS 5 on x86_64
> (http://bugs.centos.org/view.php?id 76).
>
> The fix is to avoid copying the interim key. We can simply use it in its
> original place, which is kmalloc'd.
Needs a Signed-off-by: line, but otherwise, looks good, and even saves
some stack space. Thanks for tracking this down.
-Matt
--
Matt Domsch
Linux Technology Strategist, Dell Office of the CTO
linux.dell.com & www.dell.com/linux
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] ppp_mppe: Don't put InterimKey on the stack
2007-09-21 14:40 ` Matt Domsch
@ 2007-09-21 14:47 ` Michal Schmidt
0 siblings, 0 replies; 3+ messages in thread
From: Michal Schmidt @ 2007-09-21 14:47 UTC (permalink / raw)
To: Matt Domsch; +Cc: Linux Kernel list, Frank Cusack, linux-ppp, Andrew Morton
Matt Domsch skrev:
> On Fri, Sep 21, 2007 at 04:08:09PM +0200, Michal Schmidt wrote:
>
>> Hello,
>>
>> The interrupt stack can be in the __START_KERNEL_map region in which
>> virt_to_page will not work. This caused ppp_mppe to crash on CentOS 5 on x86_64
>> (http://bugs.centos.org/view.php?id 76).
>>
>> The fix is to avoid copying the interim key. We can simply use it in its
>> original place, which is kmalloc'd.
>>
>
> Needs a Signed-off-by: line, but otherwise, looks good, and even saves
> some stack space. Thanks for tracking this down.
>
> -Matt
>
Sorry about the forgotten sign-off. Here it is.
Andrew, please apply.
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
---
drivers/net/ppp_mppe.c | 14 ++++++--------
1 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ppp_mppe.c b/drivers/net/ppp_mppe.c
index f79cf87..c0b6d19 100644
--- a/drivers/net/ppp_mppe.c
+++ b/drivers/net/ppp_mppe.c
@@ -136,7 +136,7 @@ struct ppp_mppe_state {
* Key Derivation, from RFC 3078, RFC 3079.
* Equivalent to Get_Key() for MS-CHAP as described in RFC 3079.
*/
-static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *InterimKey)
+static void get_new_key_from_sha(struct ppp_mppe_state * state)
{
struct hash_desc desc;
struct scatterlist sg[4];
@@ -153,8 +153,6 @@ static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *I
desc.flags = 0;
crypto_hash_digest(&desc, sg, nbytes, state->sha1_digest);
-
- memcpy(InterimKey, state->sha1_digest, state->keylen);
}
/*
@@ -163,21 +161,21 @@ static void get_new_key_from_sha(struct ppp_mppe_state * state, unsigned char *I
*/
static void mppe_rekey(struct ppp_mppe_state * state, int initial_key)
{
- unsigned char InterimKey[MPPE_MAX_KEY_LEN];
struct scatterlist sg_in[1], sg_out[1];
struct blkcipher_desc desc = { .tfm = state->arc4 };
- get_new_key_from_sha(state, InterimKey);
+ get_new_key_from_sha(state);
if (!initial_key) {
- crypto_blkcipher_setkey(state->arc4, InterimKey, state->keylen);
- setup_sg(sg_in, InterimKey, state->keylen);
+ crypto_blkcipher_setkey(state->arc4, state->sha1_digest,
+ state->keylen);
+ setup_sg(sg_in, state->sha1_digest, state->keylen);
setup_sg(sg_out, state->session_key, state->keylen);
if (crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
state->keylen) != 0) {
printk(KERN_WARNING "mppe_rekey: cipher_encrypt failed\n");
}
} else {
- memcpy(state->session_key, InterimKey, state->keylen);
+ memcpy(state->session_key, state->sha1_digest, state->keylen);
}
if (state->keylen = 8) {
/* See RFC 3078 */
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-09-21 14:47 UTC | newest]
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2007-09-21 14:08 [PATCH] ppp_mppe: Don't put InterimKey on the stack Michal Schmidt
2007-09-21 14:40 ` Matt Domsch
2007-09-21 14:47 ` Michal Schmidt
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