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Strengthened the consistency checks on ACLs

N2009_11_14_FIXES
jpandre 2008-12-24 15:27:34 +00:00
parent f0fbd111e0
commit 33cb0cbd7e
1 changed files with 67 additions and 38 deletions
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105
libntfs-3g/acls.c
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@ -529,6 +529,39 @@ gid_t ntfs_find_group(const struct MAPPING* groupmapping, const SID * gsid)
return (gid);
}
/*
* Check the validity of the ACEs in a DACL or SACL
*/
static BOOL valid_acl(const ACL *pacl, unsigned int end)
{
const ACCESS_ALLOWED_ACE *pace;
unsigned int offace;
unsigned int acecnt;
unsigned int acesz;
unsigned int nace;
BOOL ok;
ok = TRUE;
acecnt = le16_to_cpu(pacl->ace_count);
offace = sizeof(ACL);
for (nace = 0; (nace < acecnt) && ok; nace++) {
/* be sure the beginning is within range */
if ((offace + sizeof(ACCESS_ALLOWED_ACE)) > end)
ok = FALSE;
else {
pace = (const ACCESS_ALLOWED_ACE*)
&((const char*)pacl)[offace];
acesz = le16_to_cpu(pace->size);
if (((offace + acesz) > end)
|| !ntfs_valid_sid(&pace->sid))
ok = FALSE;
offace += acesz;
}
}
return (ok);
}
/*
* Do sanity checks on security descriptors read from storage
* basically, we make sure that every field holds within
@ -541,13 +574,12 @@ gid_t ntfs_find_group(const struct MAPPING* groupmapping, const SID * gsid)
BOOL ntfs_valid_descr(const char *securattr, unsigned int attrsz)
{
const SECURITY_DESCRIPTOR_RELATIVE *phead;
const ACL *pacl;
const ACCESS_ALLOWED_ACE *pace;
const ACL *pdacl;
const ACL *psacl;
unsigned int offdacl;
unsigned int offace;
unsigned int acecnt;
unsigned int acesz;
unsigned int nace;
unsigned int offsacl;
unsigned int offowner;
unsigned int offgroup;
BOOL ok;
ok = TRUE;
@ -560,7 +592,11 @@ BOOL ntfs_valid_descr(const char *securattr, unsigned int attrsz)
phead = (const SECURITY_DESCRIPTOR_RELATIVE*)securattr;
offdacl = le32_to_cpu(phead->dacl);
pacl = (const ACL*)&securattr[offdacl];
offsacl = le32_to_cpu(phead->sacl);
offowner = le32_to_cpu(phead->owner);
offgroup = le32_to_cpu(phead->group);
pdacl = (const ACL*)&securattr[offdacl];
psacl = (const ACL*)&securattr[offsacl];
/*
* size check occurs before the above pointers are used
@ -571,47 +607,40 @@ BOOL ntfs_valid_descr(const char *securattr, unsigned int attrsz)
if ((attrsz >= sizeof(SECURITY_DESCRIPTOR_RELATIVE))
&& (ntfs_attr_size(securattr) <= attrsz)
&& (phead->revision == SECURITY_DESCRIPTOR_REVISION)
&& phead->owner
&& phead->group
&& (offowner >= sizeof(SECURITY_DESCRIPTOR_RELATIVE))
&& ((offowner + 2) < attrsz)
&& (offgroup >= sizeof(SECURITY_DESCRIPTOR_RELATIVE))
&& ((offgroup + 2) < attrsz)
&& (!offdacl
|| ((offdacl >= sizeof(SECURITY_DESCRIPTOR_RELATIVE))
&& (offdacl < attrsz)))
&& (!offsacl
|| ((offsacl >= sizeof(SECURITY_DESCRIPTOR_RELATIVE))
&& (offsacl < attrsz)))
&& !(phead->owner & const_cpu_to_le32(3))
&& !(phead->group & const_cpu_to_le32(3))
&& !(phead->dacl & const_cpu_to_le32(3))
&& !(phead->sacl & const_cpu_to_le32(3))
&& ntfs_valid_sid((const SID*)&securattr[le32_to_cpu(phead->owner)])
&& ntfs_valid_sid((const SID*)&securattr[le32_to_cpu(phead->group)])
&& ntfs_valid_sid((const SID*)&securattr[offowner])
&& ntfs_valid_sid((const SID*)&securattr[offgroup])
/*
* if there is an ACL, as indicated by offdacl,
* require SE_DACL_PRESENT
* but "Dr Watson" has SE_DACL_PRESENT though no DACL
*/
&& (!offdacl
|| ((pacl->revision == ACL_REVISION)
&& (phead->control & SE_DACL_PRESENT)))) {
/*
* For each ACE, check it is within limits
* and contains a valid SID
* "DR Watson" has no DACL
*/
if (offdacl) {
acecnt = le16_to_cpu(pacl->ace_count);
offace = offdacl + sizeof(ACL);
for (nace = 0; (nace < acecnt) && ok; nace++) {
/* be sure the beginning is within range */
if ((offace + sizeof(ACCESS_ALLOWED_ACE)) > attrsz)
ok = FALSE;
else {
pace = (const ACCESS_ALLOWED_ACE*)
&securattr[offace];
acesz = le16_to_cpu(pace->size);
if (((offace + acesz) > attrsz)
|| !ntfs_valid_sid(&pace->sid))
ok = FALSE;
offace += acesz;
}
}
}
|| ((pdacl->revision == ACL_REVISION)
&& (phead->control & SE_DACL_PRESENT)))
/* same for SACL */
&& (!offsacl
|| ((psacl->revision == ACL_REVISION)
&& (phead->control & SE_SACL_PRESENT)))) {
/*
* Check the DACL and SACL if present
*/
if ((offdacl && !valid_acl(pdacl,attrsz - offdacl))
|| (offsacl && !valid_acl(psacl,attrsz - offsacl)))
ok = FALSE;
} else
ok = FALSE;
return (ok);