2018-07-09 22:32:23

by Tomas Bortoli

Subject: [V9fs-developer] [PATCH] version pointer uninitialized

The p9_client_version() does not initialize the version
pointer. If the call to p9pdu_readf() returns an error and version has not
been allocated in p9pdu_readf(), then the program will jump to the "error"
label and will try to free the version pointer. If version is not
initialized, free() will be called with uninitialized, garbage data and
will provoke a crash.

Signed-off-by: Tomas Bortoli <[email protected]>
Reported-by: [email protected]
---
net/9p/client.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/9p/client.c b/net/9p/client.c
index 18c5271910dc..40f7c47f2f74 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -957,7 +957,7 @@ static int p9_client_version(struct p9_client *c)
{
int err = 0;
struct p9_req_t *req;
- char *version;
+ char *version = NULL;
int msize;

p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
--
2.11.0

2018-07-10 01:04:57

by piaojun

Subject: Re: [V9fs-developer] [PATCH] version pointer uninitialized

LGTM

On 2018/7/10 6:29, Tomas Bortoli wrote:
> The p9_client_version() does not initialize the version
> pointer. If the call to p9pdu_readf() returns an error and version has not
> been allocated in p9pdu_readf(), then the program will jump to the "error"
> label and will try to free the version pointer. If version is not
> initialized, free() will be called with uninitialized, garbage data and
> will provoke a crash.
>
> Signed-off-by: Tomas Bortoli <[email protected]>
> Reported-by: [email protected]
Reviewed-by: Jun Piao <[email protected]>
> ---
> net/9p/client.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 18c5271910dc..40f7c47f2f74 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -957,7 +957,7 @@ static int p9_client_version(struct p9_client *c)
> {
> int err = 0;
> struct p9_req_t *req;
> - char *version;
> + char *version = NULL;
> int msize;
>
> p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
>

2018-07-11 01:28:57

by jiangyiwen

Subject: Re: [V9fs-developer] [PATCH] version pointer uninitialized

On 2018/7/10 6:29, Tomas Bortoli wrote:
> The p9_client_version() does not initialize the version
> pointer. If the call to p9pdu_readf() returns an error and version has not
> been allocated in p9pdu_readf(), then the program will jump to the "error"
> label and will try to free the version pointer. If version is not
> initialized, free() will be called with uninitialized, garbage data and
> will provoke a crash.
>
> Signed-off-by: Tomas Bortoli <[email protected]>

Reviewed-by: Yiwen Jiang <[email protected]>

> Reported-by: [email protected]
> ---
> net/9p/client.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 18c5271910dc..40f7c47f2f74 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -957,7 +957,7 @@ static int p9_client_version(struct p9_client *c)
> {
> int err = 0;
> struct p9_req_t *req;
> - char *version;
> + char *version = NULL;
> int msize;
>
> p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
>

2018-07-12 16:46:11

by Tomas Bortoli

Subject: Re: [V9fs-developer] [PATCH] version pointer uninitialized

On 07/11/2018 03:26 AM, jiangyiwen wrote:
> On 2018/7/10 6:29, Tomas Bortoli wrote:
>> The p9_client_version() does not initialize the version
>> pointer. If the call to p9pdu_readf() returns an error and version has not
>> been allocated in p9pdu_readf(), then the program will jump to the "error"
>> label and will try to free the version pointer. If version is not
>> initialized, free() will be called with uninitialized, garbage data and
>> will provoke a crash.
>>
>> Signed-off-by: Tomas Bortoli <[email protected]>
> Reviewed-by: Yiwen Jiang <[email protected]>
>
>> Reported-by: [email protected]
>> ---
>> net/9p/client.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/9p/client.c b/net/9p/client.c
>> index 18c5271910dc..40f7c47f2f74 100644
>> --- a/net/9p/client.c
>> +++ b/net/9p/client.c
>> @@ -957,7 +957,7 @@ static int p9_client_version(struct p9_client *c)
>> {
>> int err = 0;
>> struct p9_req_t *req;
>> - char *version;
>> + char *version = NULL;
>> int msize;
>>
>> p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
>>
>

+ Cc: Andrew Morton <[email protected]>

This goes with the other patch: [V9fs-developer] [PATCH]
p9_parse_header() validate PDU length

Tomas