malloc,free,mbtow problem
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From: Hasber on 30 Apr 2008 08:27 hi i m working on file hooking i had applied two basic hooks i.e NTCreateFile and NtOpenFile i am almost finish but with very simple error and i am unable to resolve: i am allocating dynamic memory to char pointer i.e. char *cPtrDst ; cPtrDst = (char*)malloc(size); and deallocating it by free: free(cPtrDst); and i am converting this array into wchar_t variable using : wchar_t dir[10];//suppose its an array result = mbtowc(dir,cPtrDst,size); when i compile the driver it gives error: error LNK2019: unresolved external symbol __imp__free referenced in function _freePolicyData@0 unresolved external symbol __imp__malloc referenced in function _policyWriteNeither@8 i had included stdlib.h but in vain......... any idea about error?
From: Don Burn on 30 Apr 2008 08:39 Well you are far from done for a lot of reasons. First you cannot use malloc, free or other user space calls in a kernel driver, so essentially all the code you have listed is not going to work in the kernel. But that is not the worst thing, you are hooking two calls that are easily intercepted by approved means. Hooking is extremely dangerous, and is blocked for 64-bit systems. Also, hooking drivers are flagged as MALWARE, so you have created something that is going to be looked at with disdain. Get the WDK, and some good books such as Walter Oney's "Programming the Windows Driver Model, Second Edition" and plan to take some time to understand the environment. -- Don Burn (MVP, Windows DDK) Windows 2k/XP/2k3 Filesystem and Driver Consulting Website: http://www.windrvr.com Blog: http://msmvps.com/blogs/WinDrvr Remove StopSpam to reply "Hasber" <Hasber(a)discussions.microsoft.com> wrote in message news:98B386A7-214B-4708-8EAD-455FE2397339(a)microsoft.com... > hi > i m working on file hooking > i had applied two basic hooks i.e NTCreateFile and NtOpenFile > i am almost finish but with very simple error and i am unable to resolve: > > i am allocating dynamic memory to char pointer i.e. > char *cPtrDst ; > cPtrDst = (char*)malloc(size); > and deallocating it by free: > free(cPtrDst); > > and i am converting this array into wchar_t variable > using : > wchar_t dir[10];//suppose its an array > result = mbtowc(dir,cPtrDst,size); > > > when i compile the driver it gives error: > error LNK2019: unresolved external symbol __imp__free referenced in > function > _freePolicyData@0 > > unresolved external symbol __imp__malloc referenced in function > _policyWriteNeither@8 > > i had included stdlib.h > > but in vain......... > any idea about error? > >
From: Hasber on 30 Apr 2008 08:58 I m happy that i got such a fast response well i am only working for windows XP whatever harmfull....the main thing is task which i have to accomplish ok if i cant allocate memory then can u tell me what to do for that. now do i have to use arrays. and whats about conversion of char data to wide character "Don Burn" wrote: > Well you are far from done for a lot of reasons. First you cannot use > malloc, free or other user space calls in a kernel driver, so essentially > all the code you have listed is not going to work in the kernel. > > But that is not the worst thing, you are hooking two calls that are easily > intercepted by approved means. Hooking is extremely dangerous, and is > blocked for 64-bit systems. Also, hooking drivers are flagged as MALWARE, > so you have created something that is going to be looked at with disdain. > > Get the WDK, and some good books such as Walter Oney's "Programming the > Windows Driver Model, Second Edition" and plan to take some time to > understand the environment. > > > > -- > Don Burn (MVP, Windows DDK) > Windows 2k/XP/2k3 Filesystem and Driver Consulting > Website: http://www.windrvr.com > Blog: http://msmvps.com/blogs/WinDrvr > Remove StopSpam to reply > > > "Hasber" <Hasber(a)discussions.microsoft.com> wrote in message > news:98B386A7-214B-4708-8EAD-455FE2397339(a)microsoft.com... > > hi > > i m working on file hooking > > i had applied two basic hooks i.e NTCreateFile and NtOpenFile > > i am almost finish but with very simple error and i am unable to resolve: > > > > i am allocating dynamic memory to char pointer i.e. > > char *cPtrDst ; > > cPtrDst = (char*)malloc(size); > > and deallocating it by free: > > free(cPtrDst); > > > > and i am converting this array into wchar_t variable > > using : > > wchar_t dir[10];//suppose its an array > > result = mbtowc(dir,cPtrDst,size); > > > > > > when i compile the driver it gives error: > > error LNK2019: unresolved external symbol __imp__free referenced in > > function > > _freePolicyData@0 > > > > unresolved external symbol __imp__malloc referenced in function > > _policyWriteNeither@8 > > > > i had included stdlib.h > > > > but in vain......... > > any idea about error? > > > > > > >
From: Don Burn on 30 Apr 2008 09:17 No, you can allocate memory and do conversion, but you have to use the correct API's not the c runtimes. What are you trying to do, and why do you insist on hooking? As you are obviously a newbie, the odds of your hooking without destroying the system are probably slim to none. -- Don Burn (MVP, Windows DDK) Windows 2k/XP/2k3 Filesystem and Driver Consulting Website: http://www.windrvr.com Blog: http://msmvps.com/blogs/WinDrvr Remove StopSpam to reply "Hasber" <Hasber(a)discussions.microsoft.com> wrote in message news:FEF49D69-D136-4E65-A390-A84080BAA98E(a)microsoft.com... > > I m happy that i got such a fast response > well i am only working for windows XP > whatever harmfull....the main thing is task which i have to accomplish > ok if i cant allocate memory then can u tell me what to do for that. > now do i have to use arrays. > and whats about conversion of char data to wide character > "Don Burn" wrote: > >> Well you are far from done for a lot of reasons. First you cannot use >> malloc, free or other user space calls in a kernel driver, so essentially >> all the code you have listed is not going to work in the kernel. >> >> But that is not the worst thing, you are hooking two calls that are >> easily >> intercepted by approved means. Hooking is extremely dangerous, and is >> blocked for 64-bit systems. Also, hooking drivers are flagged as >> MALWARE, >> so you have created something that is going to be looked at with disdain. >> >> Get the WDK, and some good books such as Walter Oney's "Programming the >> Windows Driver Model, Second Edition" and plan to take some time to >> understand the environment. >> >> >> >> -- >> Don Burn (MVP, Windows DDK) >> Windows 2k/XP/2k3 Filesystem and Driver Consulting >> Website: http://www.windrvr.com >> Blog: http://msmvps.com/blogs/WinDrvr >> Remove StopSpam to reply >> >> >> "Hasber" <Hasber(a)discussions.microsoft.com> wrote in message >> news:98B386A7-214B-4708-8EAD-455FE2397339(a)microsoft.com... >> > hi >> > i m working on file hooking >> > i had applied two basic hooks i.e NTCreateFile and NtOpenFile >> > i am almost finish but with very simple error and i am unable to >> > resolve: >> > >> > i am allocating dynamic memory to char pointer i.e. >> > char *cPtrDst ; >> > cPtrDst = (char*)malloc(size); >> > and deallocating it by free: >> > free(cPtrDst); >> > >> > and i am converting this array into wchar_t variable >> > using : >> > wchar_t dir[10];//suppose its an array >> > result = mbtowc(dir,cPtrDst,size); >> > >> > >> > when i compile the driver it gives error: >> > error LNK2019: unresolved external symbol __imp__free referenced in >> > function >> > _freePolicyData@0 >> > >> > unresolved external symbol __imp__malloc referenced in function >> > _policyWriteNeither@8 >> > >> > i had included stdlib.h >> > >> > but in vain......... >> > any idea about error? >> > >> > >> >> >>
From: Hasber on 30 Apr 2008 09:51
well mr don i am working on a project which will restrict the malicious movement of files across network or any physical media in which i will apply policy like "block delete access of txt files" "block copy paste access of pdf" to do so what i got is just hook the functions. i know now that i cant use it in vista. now do guide me what shud i adopt to work bcoz i have to rewrite things again. "Don Burn" wrote: > No, you can allocate memory and do conversion, but you have to use the > correct API's not the c runtimes. What are you trying to do, and why do you > insist on hooking? As you are obviously a newbie, the odds of your hooking > without destroying the system are probably slim to none. > > > -- > Don Burn (MVP, Windows DDK) > Windows 2k/XP/2k3 Filesystem and Driver Consulting > Website: http://www.windrvr.com > Blog: http://msmvps.com/blogs/WinDrvr > Remove StopSpam to reply > > > > > "Hasber" <Hasber(a)discussions.microsoft.com> wrote in message > news:FEF49D69-D136-4E65-A390-A84080BAA98E(a)microsoft.com... > > > > I m happy that i got such a fast response > > well i am only working for windows XP > > whatever harmfull....the main thing is task which i have to accomplish > > ok if i cant allocate memory then can u tell me what to do for that. > > now do i have to use arrays. > > and whats about conversion of char data to wide character > > "Don Burn" wrote: > > > >> Well you are far from done for a lot of reasons. First you cannot use > >> malloc, free or other user space calls in a kernel driver, so essentially > >> all the code you have listed is not going to work in the kernel. > >> > >> But that is not the worst thing, you are hooking two calls that are > >> easily > >> intercepted by approved means. Hooking is extremely dangerous, and is > >> blocked for 64-bit systems. Also, hooking drivers are flagged as > >> MALWARE, > >> so you have created something that is going to be looked at with disdain. > >> > >> Get the WDK, and some good books such as Walter Oney's "Programming the > >> Windows Driver Model, Second Edition" and plan to take some time to > >> understand the environment. > >> > >> > >> > >> -- > >> Don Burn (MVP, Windows DDK) > >> Windows 2k/XP/2k3 Filesystem and Driver Consulting > >> Website: http://www.windrvr.com > >> Blog: http://msmvps.com/blogs/WinDrvr > >> Remove StopSpam to reply > >> > >> > >> "Hasber" <Hasber(a)discussions.microsoft.com> wrote in message > >> news:98B386A7-214B-4708-8EAD-455FE2397339(a)microsoft.com... > >> > hi > >> > i m working on file hooking > >> > i had applied two basic hooks i.e NTCreateFile and NtOpenFile > >> > i am almost finish but with very simple error and i am unable to > >> > resolve: > >> > > >> > i am allocating dynamic memory to char pointer i.e. > >> > char *cPtrDst ; > >> > cPtrDst = (char*)malloc(size); > >> > and deallocating it by free: > >> > free(cPtrDst); > >> > > >> > and i am converting this array into wchar_t variable > >> > using : > >> > wchar_t dir[10];//suppose its an array > >> > result = mbtowc(dir,cPtrDst,size); > >> > > >> > > >> > when i compile the driver it gives error: > >> > error LNK2019: unresolved external symbol __imp__free referenced in > >> > function > >> > _freePolicyData@0 > >> > > >> > unresolved external symbol __imp__malloc referenced in function > >> > _policyWriteNeither@8 > >> > > >> > i had included stdlib.h > >> > > >> > but in vain......... > >> > any idea about error? > >> > > >> > > >> > >> > >> > > > |