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842aafc888
This query uses data flow for nullness analysis, which is always going to be a large overapproximation. The overapproximation became too big for one of the test cases after the recent change to make data flow go across assignment by reference. To make this query more conservative, it will now only report that the `pDacl` argument can be null if there isn't also evidence that it can be non-null.
133 lines
3.1 KiB
C++
133 lines
3.1 KiB
C++
// semmle-extractor-options: --microsoft
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typedef unsigned long DWORD;
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typedef unsigned long ULONG;
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typedef unsigned char BYTE;
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typedef unsigned short WORD;
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typedef int BOOL;
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typedef void *PVOID;
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#define TRUE 1
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#define FALSE 0
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#define ERROR_SUCCESS 0L
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#define NULL 0
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typedef PVOID PSECURITY_DESCRIPTOR;
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typedef struct _ACL {
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BYTE AclRevision;
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BYTE Sbz1;
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WORD AclSize;
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WORD AceCount;
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WORD Sbz2;
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} ACL;
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typedef ACL *PACL;
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typedef enum _ACCESS_MODE
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{
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NOT_USED_ACCESS = 0,
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GRANT_ACCESS,
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SET_ACCESS,
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DENY_ACCESS,
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REVOKE_ACCESS,
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SET_AUDIT_SUCCESS,
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SET_AUDIT_FAILURE
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} ACCESS_MODE;
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typedef int TRUSTEE_W;
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typedef struct _EXPLICIT_ACCESS_W
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{
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DWORD grfAccessPermissions;
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ACCESS_MODE grfAccessMode;
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DWORD grfInheritance;
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TRUSTEE_W Trustee;
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} EXPLICIT_ACCESS_W, *PEXPLICIT_ACCESS_W, EXPLICIT_ACCESSW, *PEXPLICIT_ACCESSW;
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BOOL
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SetSecurityDescriptorDacl(
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PSECURITY_DESCRIPTOR pSecurityDescriptor,
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BOOL bDaclPresent,
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PACL pDacl,
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BOOL bDaclDefaulted
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) {
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return TRUE;
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}
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DWORD SetEntriesInAcl(
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ULONG cCountOfExplicitEntries,
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PEXPLICIT_ACCESS_W pListOfExplicitEntries,
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PACL OldAcl,
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PACL *NewAcl
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)
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{
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*NewAcl = (PACL)0xFFFFFF;
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return ERROR_SUCCESS;
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}
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void Test()
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{
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PSECURITY_DESCRIPTOR pSecurityDescriptor;
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BOOL b;
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b = SetSecurityDescriptorDacl(pSecurityDescriptor,
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TRUE, // Dacl Present
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NULL, // NULL pointer to DACL == BUG
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FALSE);
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PACL pDacl = NULL;
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b = SetSecurityDescriptorDacl(pSecurityDescriptor,
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TRUE, // Dacl Present
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pDacl, // NULL pointer to DACL == BUG
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FALSE);
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SetEntriesInAcl(0, NULL, NULL, &pDacl);
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b = SetSecurityDescriptorDacl(pSecurityDescriptor,
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TRUE, // Dacl Present
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pDacl, // Should have been set by SetEntriesInAcl ==> should not be flagged
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FALSE);
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b = SetSecurityDescriptorDacl(pSecurityDescriptor,
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FALSE, // Dacl is not Present
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NULL, // DACL is going to be removed from security descriptor. Default/inherited access ==> should not be flagged
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FALSE);
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}
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PACL returnUnknownAcl();
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PACL returnNull() {
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return NULL;
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}
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PACL returnMaybeAcl(bool b) {
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PACL pDacl = NULL;
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if (b) {
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SetEntriesInAcl(0, NULL, NULL, &pDacl);
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}
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return pDacl;
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}
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void Test2()
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{
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PSECURITY_DESCRIPTOR pSecurityDescriptor;
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PACL pDacl1 = returnUnknownAcl();
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SetSecurityDescriptorDacl(
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pSecurityDescriptor,
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TRUE, // Dacl Present
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pDacl1, // Give `returnUnknownAcl` the benefit of the doubt ==> should not be flagged
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FALSE);
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PACL pDacl2 = returnNull();
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SetSecurityDescriptorDacl(
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pSecurityDescriptor,
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TRUE, // Dacl Present
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pDacl2, // NULL pointer to DACL == BUG
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FALSE);
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PACL pDacl3 = returnMaybeAcl(true);
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SetSecurityDescriptorDacl(
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pSecurityDescriptor,
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TRUE, // Dacl Present
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pDacl3, // should not be flagged
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FALSE);
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}
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