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dprintf: use user_memcpy/user_strlcpy to read the user buffer. 

* also check the user buffer address.
This commit is contained in:
Jérôme Duval 2018-01-08 21:36:25 +01:00
parent a31e05bb68
commit d9e4ef3f76
1 changed files with 11 additions and 2 deletions
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13
src/add-ons/kernel/drivers/common/dprintf.cpp
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@ -11,6 +11,7 @@
#include <debug.h>
#include <kernel.h>
#include <Drivers.h>
#include <KernelExport.h>
@ -70,11 +71,19 @@ dprintf_read(void *cookie, off_t pos, void *buffer, size_t *length)
static status_t
dprintf_write(void *cookie, off_t pos, const void *buffer, size_t *_length)
{
if (!IS_USER_ADDRESS(buffer))
return B_BAD_ADDRESS;
const char *str = (const char*)buffer;
int bytesLeft = *_length;
while (bytesLeft > 0) {
int chunkSize = strnlen(str, bytesLeft);
ssize_t size = user_strlcpy(NULL, str, 0);
// there's no user_strnlen()
if (size < 0)
return 0;
int chunkSize = min_c(bytesLeft, (int)size);
// int chunkSize = strnlen(str, bytesLeft);
if (chunkSize == 0) {
// null bytes -- skip
str++;
@ -91,7 +100,7 @@ dprintf_write(void *cookie, off_t pos, const void *buffer, size_t *_length)
char localBuffer[512];
if (bytesLeft > (int)sizeof(localBuffer) - 1)
chunkSize = (int)sizeof(localBuffer) - 1;
memcpy(localBuffer, str, chunkSize);
user_memcpy(localBuffer, str, chunkSize);
localBuffer[chunkSize] = '\0';
debug_puts(localBuffer, chunkSize);