Hello Maintainers:
in arch/powerpc/kernel/lparcfg.c, parse_system_parameter_string()
need set '\0' for 'local_buffer'.
the reason is:
SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096
the contents of rtas_data_buf may truncated in memcpy (line 301).
if contents are truncated.
the splpar_strlen is more than 1026 (line 321)
the while loop checking will not find the end of buffer (line 326)
it will cause memory access violation.
I find it by reading code, so please help check.
thanks.
gchen.
-------------------------related fix patch--------------------------------------
diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 801a757..d92f387 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -299,6 +299,7 @@ static void parse_system_parameter_string(struct seq_file *m)
__pa(rtas_data_buf),
RTAS_DATA_BUF_SIZE);
memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
+ local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
spin_unlock(&rtas_data_buf_lock);
if (call_status != 0) {
-------------------------related source code------------------------------------
283 static void parse_system_parameter_string(struct seq_file *m)
284 {
285 int call_status;
286
287 unsigned char *local_buffer = kmalloc(SPLPAR_MAXLENGTH, GFP_KERNEL);
288 if (!local_buffer) {
289 printk(KERN_ERR "%s %s kmalloc failure at line %d\n",
290 __FILE__, __func__, __LINE__);
291 return;
292 }
293
294 spin_lock(&rtas_data_buf_lock);
295 memset(rtas_data_buf, 0, SPLPAR_MAXLENGTH);
296 call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
297 NULL,
298 SPLPAR_CHARACTERISTICS_TOKEN,
299 __pa(rtas_data_buf),
300 RTAS_DATA_BUF_SIZE);
301 memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
302 spin_unlock(&rtas_data_buf_lock);
303
304 if (call_status != 0) {
305 printk(KERN_INFO
306 "%s %s Error calling get-system-parameter (0x%x)\n",
307 __FILE__, __func__, call_status);
308 } else {
309 int splpar_strlen;
310 int idx, w_idx;
311 char *workbuffer = kzalloc(SPLPAR_MAXLENGTH, GFP_KERNEL);
312 if (!workbuffer) {
313 printk(KERN_ERR "%s %s kmalloc failure at line %d\n",
314 __FILE__, __func__, __LINE__);
315 kfree(local_buffer);
316 return;
317 }
318 #ifdef LPARCFG_DEBUG
319 printk(KERN_INFO "success calling get-system-parameter\n");
320 #endif
321 splpar_strlen = local_buffer[0] * 256 + local_buffer[1];
322 local_buffer += 2; /* step over strlen value */
323
324 w_idx = 0;
325 idx = 0;
326 while ((*local_buffer) && (idx < splpar_strlen)) {
327 workbuffer[w_idx++] = local_buffer[idx++];
328 if ((local_buffer[idx] == ',')
329 || (local_buffer[idx] == '\0')) {
330 workbuffer[w_idx] = '\0';
331 if (w_idx) {
332 /* avoid the empty string */
333 seq_printf(m, "%s\n", workbuffer);
334 }
335 memset(workbuffer, 0, SPLPAR_MAXLENGTH);
336 idx++; /* skip the comma */
337 w_idx = 0;
338 } else if (local_buffer[idx] == '=') {
339 /* code here to replace workbuffer contents
340 with different keyword strings */
341 if (0 == strcmp(workbuffer, "MaxEntCap")) {
342 strcpy(workbuffer,
343 "partition_max_entitled_capacity");
344 w_idx = strlen(workbuffer);
345 }
346 if (0 == strcmp(workbuffer, "MaxPlatProcs")) {
347 strcpy(workbuffer,
348 "system_potential_processors");
349 w_idx = strlen(workbuffer);
350 }
351 }
352 }
353 kfree(workbuffer);
354 local_buffer -= 2; /* back up over strlen value */
355 }
356 kfree(local_buffer);
357 }
On Thu, 2013-04-18 at 12:45 +0800, Chen Gang wrote:
> Hello Maintainers:
>
>
> in arch/powerpc/kernel/lparcfg.c, parse_system_parameter_string()
>
> need set '\0' for 'local_buffer'.
>
> the reason is:
> SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096
> the contents of rtas_data_buf may truncated in memcpy (line 301).
>
> if contents are truncated.
> the splpar_strlen is more than 1026 (line 321)
> the while loop checking will not find the end of buffer (line 326)
> it will cause memory access violation.
>
>
> I find it by reading code, so please help check.
And a signed-off-by please ?
Cheers,
Ben.
> thanks.
>
> gchen.
>
> -------------------------related fix patch--------------------------------------
>
> diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
> index 801a757..d92f387 100644
> --- a/arch/powerpc/kernel/lparcfg.c
> +++ b/arch/powerpc/kernel/lparcfg.c
> @@ -299,6 +299,7 @@ static void parse_system_parameter_string(struct seq_file *m)
> __pa(rtas_data_buf),
> RTAS_DATA_BUF_SIZE);
> memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
> + local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
> spin_unlock(&rtas_data_buf_lock);
>
> if (call_status != 0) {
>
>
>
> -------------------------related source code------------------------------------
>
>
> 283 static void parse_system_parameter_string(struct seq_file *m)
> 284 {
> 285 int call_status;
> 286
> 287 unsigned char *local_buffer = kmalloc(SPLPAR_MAXLENGTH, GFP_KERNEL);
> 288 if (!local_buffer) {
> 289 printk(KERN_ERR "%s %s kmalloc failure at line %d\n",
> 290 __FILE__, __func__, __LINE__);
> 291 return;
> 292 }
> 293
> 294 spin_lock(&rtas_data_buf_lock);
> 295 memset(rtas_data_buf, 0, SPLPAR_MAXLENGTH);
> 296 call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
> 297 NULL,
> 298 SPLPAR_CHARACTERISTICS_TOKEN,
> 299 __pa(rtas_data_buf),
> 300 RTAS_DATA_BUF_SIZE);
> 301 memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
> 302 spin_unlock(&rtas_data_buf_lock);
> 303
> 304 if (call_status != 0) {
> 305 printk(KERN_INFO
> 306 "%s %s Error calling get-system-parameter (0x%x)\n",
> 307 __FILE__, __func__, call_status);
> 308 } else {
> 309 int splpar_strlen;
> 310 int idx, w_idx;
> 311 char *workbuffer = kzalloc(SPLPAR_MAXLENGTH, GFP_KERNEL);
> 312 if (!workbuffer) {
> 313 printk(KERN_ERR "%s %s kmalloc failure at line %d\n",
> 314 __FILE__, __func__, __LINE__);
> 315 kfree(local_buffer);
> 316 return;
> 317 }
> 318 #ifdef LPARCFG_DEBUG
> 319 printk(KERN_INFO "success calling get-system-parameter\n");
> 320 #endif
> 321 splpar_strlen = local_buffer[0] * 256 + local_buffer[1];
> 322 local_buffer += 2; /* step over strlen value */
> 323
> 324 w_idx = 0;
> 325 idx = 0;
> 326 while ((*local_buffer) && (idx < splpar_strlen)) {
> 327 workbuffer[w_idx++] = local_buffer[idx++];
> 328 if ((local_buffer[idx] == ',')
> 329 || (local_buffer[idx] == '\0')) {
> 330 workbuffer[w_idx] = '\0';
> 331 if (w_idx) {
> 332 /* avoid the empty string */
> 333 seq_printf(m, "%s\n", workbuffer);
> 334 }
> 335 memset(workbuffer, 0, SPLPAR_MAXLENGTH);
> 336 idx++; /* skip the comma */
> 337 w_idx = 0;
> 338 } else if (local_buffer[idx] == '=') {
> 339 /* code here to replace workbuffer contents
> 340 with different keyword strings */
> 341 if (0 == strcmp(workbuffer, "MaxEntCap")) {
> 342 strcpy(workbuffer,
> 343 "partition_max_entitled_capacity");
> 344 w_idx = strlen(workbuffer);
> 345 }
> 346 if (0 == strcmp(workbuffer, "MaxPlatProcs")) {
> 347 strcpy(workbuffer,
> 348 "system_potential_processors");
> 349 w_idx = strlen(workbuffer);
> 350 }
> 351 }
> 352 }
> 353 kfree(workbuffer);
> 354 local_buffer -= 2; /* back up over strlen value */
> 355 }
> 356 kfree(local_buffer);
> 357 }
On 2013年04月23日 08:31, Benjamin Herrenschmidt wrote:
> On Thu, 2013-04-18 at 12:45 +0800, Chen Gang wrote:
>> Hello Maintainers:
>>
>>
>> in arch/powerpc/kernel/lparcfg.c, parse_system_parameter_string()
>>
>> need set '\0' for 'local_buffer'.
>>
>> the reason is:
>> SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096
>> the contents of rtas_data_buf may truncated in memcpy (line 301).
>>
>> if contents are truncated.
>> the splpar_strlen is more than 1026 (line 321)
>> the while loop checking will not find the end of buffer (line 326)
>> it will cause memory access violation.
>>
>>
>> I find it by reading code, so please help check.
>
> And a signed-off-by please ?
>
ok, thanks, I should send the related patch.
--
Chen Gang
Asianux Corporation
need set '\0' for 'local_buffer'.
SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
rtas_data_buf may truncated in memcpy.
if contents are really truncated.
the splpar_strlen is more than 1026. the next while loop checking will
not find the end of buffer. that will cause memory access violation.
Signed-off-by: Chen Gang <[email protected]>
---
arch/powerpc/kernel/lparcfg.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 801a757..d92f387 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -299,6 +299,7 @@ static void parse_system_parameter_string(struct seq_file *m)
__pa(rtas_data_buf),
RTAS_DATA_BUF_SIZE);
memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
+ local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
spin_unlock(&rtas_data_buf_lock);
if (call_status != 0) {
--
1.7.7.6
On 04/23/2013 08:42 AM, Chen Gang wrote:
>
> need set '\0' for 'local_buffer'.
>
> SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
> rtas_data_buf may truncated in memcpy.
>
> if contents are really truncated.
> the splpar_strlen is more than 1026. the next while loop checking will
> not find the end of buffer. that will cause memory access violation.
>
Per parameter length in ibm,get-system-parameter RTAS call is limited to 1026
bytes (1024 bytes of data + 2 bytes length). And 'rtas_data_buf' was set to 0
(first 1026 bytes) before call RTAS call. At the worst if we get junk in RTAS
output length field helps to exit from the while loop. So I don't think we need
this patch.
-Vasant
>
> Signed-off-by: Chen Gang<[email protected]>
> ---
> arch/powerpc/kernel/lparcfg.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
> index 801a757..d92f387 100644
> --- a/arch/powerpc/kernel/lparcfg.c
> +++ b/arch/powerpc/kernel/lparcfg.c
> @@ -299,6 +299,7 @@ static void parse_system_parameter_string(struct seq_file *m)
> __pa(rtas_data_buf),
> RTAS_DATA_BUF_SIZE);
> memcpy(local_buffer, rtas_data_buf, SPLPAR_MAXLENGTH);
> + local_buffer[SPLPAR_MAXLENGTH - 1] = '\0';
> spin_unlock(&rtas_data_buf_lock);
>
> if (call_status != 0) {
On 2013年04月24日 14:28, Vasant Hegde wrote:
> On 04/23/2013 08:42 AM, Chen Gang wrote:
>>
>> need set '\0' for 'local_buffer'.
>>
>> SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
>> rtas_data_buf may truncated in memcpy.
>>
>> if contents are really truncated.
>> the splpar_strlen is more than 1026. the next while loop checking will
>> not find the end of buffer. that will cause memory access violation.
>>
>
> Per parameter length in ibm,get-system-parameter RTAS call is limited to
> 1026 bytes (1024 bytes of data + 2 bytes length). And 'rtas_data_buf'
> was set to 0 (first 1026 bytes) before call RTAS call. At the worst if
> we get junk in RTAS output length field helps to exit from the while
> loop. So I don't think we need this patch.
Is get-system-parameter return the NUL terminated string ? if so, it
will no issue (just like your discription).
If it will not return NUL terminated string, please see line 326:
"while ((*local_buffer) && (idx < splpar_strlen))"
(when idx == 1024, *local_buffer is memory access violation).
Since we use the first 2 bytes as length, and also be sure of the real
length will never more than 1024, I suggest to:
---------------------------patch begin--------------------------------
diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
index 801a757..f8bd7cf 100644
--- a/arch/powerpc/kernel/lparcfg.c
+++ b/arch/powerpc/kernel/lparcfg.c
@@ -323,7 +323,7 @@ static void parse_system_parameter_string(struct seq_file *m)
w_idx = 0;
idx = 0;
- while ((*local_buffer) && (idx < splpar_strlen)) {
+ while (idx < splpar_strlen) {
workbuffer[w_idx++] = local_buffer[idx++];
if ((local_buffer[idx] == ',')
|| (local_buffer[idx] == '\0')) {
---------------------------patch end----------------------------------
Thanks.
--
Chen Gang
Asianux Corporation
On 04/24/2013 12:33 PM, Chen Gang wrote:
> On 2013年04月24日 14:28, Vasant Hegde wrote:
>> On 04/23/2013 08:42 AM, Chen Gang wrote:
>>>
>>> need set '\0' for 'local_buffer'.
>>>
>>> SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the contents of
>>> rtas_data_buf may truncated in memcpy.
>>>
>>> if contents are really truncated.
>>> the splpar_strlen is more than 1026. the next while loop checking will
>>> not find the end of buffer. that will cause memory access violation.
>>>
>>
>> Per parameter length in ibm,get-system-parameter RTAS call is limited to
>> 1026 bytes (1024 bytes of data + 2 bytes length). And 'rtas_data_buf'
>> was set to 0 (first 1026 bytes) before call RTAS call. At the worst if
>> we get junk in RTAS output length field helps to exit from the while
>> loop. So I don't think we need this patch.
>
> Is get-system-parameter return the NUL terminated string ? if so, it
> will no issue (just like your discription).
>
Length includes the length of the NULL. So (idx < splpar_strlen)
is safe. IMO existing code is proper.
-Vasant
> If it will not return NUL terminated string, please see line 326:
>
> "while ((*local_buffer)&& (idx< splpar_strlen))"
> (when idx == 1024, *local_buffer is memory access violation).
>
> Since we use the first 2 bytes as length, and also be sure of the real
> length will never more than 1024, I suggest to:
>
> ---------------------------patch begin--------------------------------
>
> diff --git a/arch/powerpc/kernel/lparcfg.c b/arch/powerpc/kernel/lparcfg.c
> index 801a757..f8bd7cf 100644
> --- a/arch/powerpc/kernel/lparcfg.c
> +++ b/arch/powerpc/kernel/lparcfg.c
> @@ -323,7 +323,7 @@ static void parse_system_parameter_string(struct seq_file *m)
>
> w_idx = 0;
> idx = 0;
> - while ((*local_buffer)&& (idx< splpar_strlen)) {
> + while (idx< splpar_strlen) {
> workbuffer[w_idx++] = local_buffer[idx++];
> if ((local_buffer[idx] == ',')
> || (local_buffer[idx] == '\0')) {
>
> ---------------------------patch end----------------------------------
>
> Thanks.
>
On 2013年04月24日 15:23, Vasant Hegde wrote:
> On 04/24/2013 12:33 PM, Chen Gang wrote:
>> On 2013年04月24日 14:28, Vasant Hegde wrote:
>>> On 04/23/2013 08:42 AM, Chen Gang wrote:
>>>>
>>>> need set '\0' for 'local_buffer'.
>>>>
>>>> SPLPAR_MAXLENGTH is 1026, RTAS_DATA_BUF_SIZE is 4096. so the
>>>> contents of
>>>> rtas_data_buf may truncated in memcpy.
>>>>
>>>> if contents are really truncated.
>>>> the splpar_strlen is more than 1026. the next while loop
>>>> checking will
>>>> not find the end of buffer. that will cause memory access
>>>> violation.
>>>>
>>>
>>> Per parameter length in ibm,get-system-parameter RTAS call is limited to
>>> 1026 bytes (1024 bytes of data + 2 bytes length). And 'rtas_data_buf'
>>> was set to 0 (first 1026 bytes) before call RTAS call. At the worst if
>>> we get junk in RTAS output length field helps to exit from the while
>>> loop. So I don't think we need this patch.
>>
>> Is get-system-parameter return the NUL terminated string ? if so, it
>> will no issue (just like your discription).
>>
>
> Length includes the length of the NULL. So (idx < splpar_strlen)
> is safe. IMO existing code is proper.
OK, since it is not an issue, I will try another patches for powerpc POWER7.
:-)
--
Chen Gang
Asianux Corporation