1 files changed, 143 insertions, 69 deletions

diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index ef4784e72b1d..9b7f727b0e88 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -557,30 +557,37 @@ static void copy_sec_desc(const struct cifs_ntsd *pntsd,
    bits to set can be: S_IRWXU, S_IRWXG or S_IRWXO ie 00700 or 00070 or 00007
 */
 static void access_flags_to_mode(__le32 ace_flags, int type, umode_t *pmode,
-				 umode_t *pbits_to_set)
+				 umode_t *pdenied, umode_t mask)
 {
 	__u32 flags = le32_to_cpu(ace_flags);
-	/* the order of ACEs is important.  The canonical order is to begin with
-	   DENY entries followed by ALLOW, otherwise an allow entry could be
-	   encountered first, making the subsequent deny entry like "dead code"
-	   which would be superflous since Windows stops when a match is made
-	   for the operation you are trying to perform for your user */
-
-	/* For deny ACEs we change the mask so that subsequent allow access
-	   control entries do not turn on the bits we are denying */
+	/*
+	 * Do not assume "preferred" or "canonical" order.
+	 * The first DENY or ALLOW ACE which matches perfectly is
+	 * the permission to be used. Once allowed or denied, same
+	 * permission in later ACEs do not matter.
+	 */
+
+	/* If not already allowed, deny these bits */
 	if (type == ACCESS_DENIED) {
-		if (flags & GENERIC_ALL)
-			*pbits_to_set &= ~S_IRWXUGO;
-
-		if ((flags & GENERIC_WRITE) ||
-			((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
-			*pbits_to_set &= ~S_IWUGO;
-		if ((flags & GENERIC_READ) ||
-			((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
-			*pbits_to_set &= ~S_IRUGO;
-		if ((flags & GENERIC_EXECUTE) ||
-			((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
-			*pbits_to_set &= ~S_IXUGO;
+		if (flags & GENERIC_ALL &&
+				!(*pmode & mask & 0777))
+			*pdenied |= mask & 0777;
+
+		if (((flags & GENERIC_WRITE) ||
+				((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS)) &&
+				!(*pmode & mask & 0222))
+			*pdenied |= mask & 0222;
+
+		if (((flags & GENERIC_READ) ||
+				((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS)) &&
+				!(*pmode & mask & 0444))
+			*pdenied |= mask & 0444;
+
+		if (((flags & GENERIC_EXECUTE) ||
+				((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS)) &&
+				!(*pmode & mask & 0111))
+			*pdenied |= mask & 0111;
+
 		return;
 	} else if (type != ACCESS_ALLOWED) {
 		cifs_dbg(VFS, "unknown access control type %d\n", type);
@@ -588,20 +595,27 @@ static void access_flags_to_mode(__le32 ace_flags, int type, umode_t *pmode,
 	}
 	/* else ACCESS_ALLOWED type */
 
-	if (flags & GENERIC_ALL) {
-		*pmode |= (S_IRWXUGO & (*pbits_to_set));
+	if ((flags & GENERIC_ALL) &&
+			!(*pdenied & mask & 0777)) {
+		*pmode |= mask & 0777;
 		cifs_dbg(NOISY, "all perms\n");
 		return;
 	}
-	if ((flags & GENERIC_WRITE) ||
-			((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
-		*pmode |= (S_IWUGO & (*pbits_to_set));
-	if ((flags & GENERIC_READ) ||
-			((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
-		*pmode |= (S_IRUGO & (*pbits_to_set));
-	if ((flags & GENERIC_EXECUTE) ||
-			((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
-		*pmode |= (S_IXUGO & (*pbits_to_set));
+
+	if (((flags & GENERIC_WRITE) ||
+			((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS)) &&
+			!(*pdenied & mask & 0222))
+		*pmode |= mask & 0222;
+
+	if (((flags & GENERIC_READ) ||
+			((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS)) &&
+			!(*pdenied & mask & 0444))
+		*pmode |= mask & 0444;
+
+	if (((flags & GENERIC_EXECUTE) ||
+			((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS)) &&
+			!(*pdenied & mask & 0111))
+		*pmode |= mask & 0111;
 
 	cifs_dbg(NOISY, "access flags 0x%x mode now %04o\n", flags, *pmode);
 	return;
@@ -638,17 +652,19 @@ static void mode_to_access_flags(umode_t mode, umode_t bits_to_use,
 }
 
 static __u16 fill_ace_for_sid(struct cifs_ace *pntace,
-			const struct cifs_sid *psid, __u64 nmode, umode_t bits)
+			const struct cifs_sid *psid, __u64 nmode, umode_t bits, __u8 access_type)
 {
 	int i;
 	__u16 size = 0;
 	__u32 access_req = 0;
 
-	pntace->type = ACCESS_ALLOWED;
+	pntace->type = access_type;
 	pntace->flags = 0x0;
 	mode_to_access_flags(nmode, bits, &access_req);
-	if (!access_req)
+	if (access_type == ACCESS_ALLOWED && !access_req)
 		access_req = SET_MINIMUM_RIGHTS;
+	else if (access_type == ACCESS_DENIED)
+		access_req &= ~SET_MINIMUM_RIGHTS;
 	pntace->access_req = cpu_to_le32(access_req);
 
 	pntace->sid.revision = psid->revision;
@@ -701,6 +717,10 @@ static void dump_ace(struct cifs_ace *pace, char *end_of_acl)
 }
 #endif
 
+#define ACL_OWNER_MASK 0700
+#define ACL_GROUP_MASK 0770
+#define ACL_EVERYONE_MASK 0777
+
 static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
 		       struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
 		       struct cifs_fattr *fattr, bool mode_from_special_sid)
@@ -716,7 +736,7 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
 	if (!pdacl) {
 		/* no DACL in the security descriptor, set
 		   all the permissions for user/group/other */
-		fattr->cf_mode |= S_IRWXUGO;
+		fattr->cf_mode |= 0777;
 		return;
 	}
 
@@ -733,16 +753,14 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
 	/* reset rwx permissions for user/group/other.
 	   Also, if num_aces is 0 i.e. DACL has no ACEs,
 	   user/group/other have no permissions */
-	fattr->cf_mode &= ~(S_IRWXUGO);
+	fattr->cf_mode &= ~(0777);
 
 	acl_base = (char *)pdacl;
 	acl_size = sizeof(struct cifs_acl);
 
 	num_aces = le32_to_cpu(pdacl->num_aces);
 	if (num_aces > 0) {
-		umode_t user_mask = S_IRWXU;
-		umode_t group_mask = S_IRWXG;
-		umode_t other_mask = S_IRWXU | S_IRWXG | S_IRWXO;
+		umode_t denied_mode = 0;
 
 		if (num_aces > ULONG_MAX / sizeof(struct cifs_ace *))
 			return;
@@ -768,26 +786,28 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
 				fattr->cf_mode |=
 					le32_to_cpu(ppace[i]->sid.sub_auth[2]);
 				break;
-			} else if (compare_sids(&(ppace[i]->sid), pownersid) == 0)
-				access_flags_to_mode(ppace[i]->access_req,
-						     ppace[i]->type,
-						     &fattr->cf_mode,
-						     &user_mask);
-			else if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0)
-				access_flags_to_mode(ppace[i]->access_req,
-						     ppace[i]->type,
-						     &fattr->cf_mode,
-						     &group_mask);
-			else if (compare_sids(&(ppace[i]->sid), &sid_everyone) == 0)
-				access_flags_to_mode(ppace[i]->access_req,
-						     ppace[i]->type,
-						     &fattr->cf_mode,
-						     &other_mask);
-			else if (compare_sids(&(ppace[i]->sid), &sid_authusers) == 0)
-				access_flags_to_mode(ppace[i]->access_req,
-						     ppace[i]->type,
-						     &fattr->cf_mode,
-						     &other_mask);
+			} else {
+				if (compare_sids(&(ppace[i]->sid), pownersid) == 0) {
+					access_flags_to_mode(ppace[i]->access_req,
+							ppace[i]->type,
+							&fattr->cf_mode,
+							&denied_mode,
+							ACL_OWNER_MASK);
+				} else if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0) {
+					access_flags_to_mode(ppace[i]->access_req,
+							ppace[i]->type,
+							&fattr->cf_mode,
+							&denied_mode,
+							ACL_GROUP_MASK);
+				} else if ((compare_sids(&(ppace[i]->sid), &sid_everyone) == 0) ||
+						(compare_sids(&(ppace[i]->sid), &sid_authusers) == 0)) {
+					access_flags_to_mode(ppace[i]->access_req,
+							ppace[i]->type,
+							&fattr->cf_mode,
+							&denied_mode,
+							ACL_EVERYONE_MASK);
+				}
+			}
 
 
 /*			memcpy((void *)(&(cifscred->aces[i])),
@@ -873,32 +893,86 @@ unsigned int setup_special_user_owner_ACE(struct cifs_ace *pntace)
 }
 
 static int set_chmod_dacl(struct cifs_acl *pndacl, struct cifs_sid *pownersid,
-			struct cifs_sid *pgrpsid, __u64 nmode, bool modefromsid)
+			struct cifs_sid *pgrpsid, __u64 *pnmode, bool modefromsid)
 {
 	u16 size = 0;
 	u32 num_aces = 0;
 	struct cifs_acl *pnndacl;
+	__u64 nmode;
+	__u64 user_mode;
+	__u64 group_mode;
+	__u64 other_mode;
+	__u64 deny_user_mode = 0;
+	__u64 deny_group_mode = 0;
 
 	pnndacl = (struct cifs_acl *)((char *)pndacl + sizeof(struct cifs_acl));
 
+	nmode = *pnmode;
+
 	if (modefromsid) {
 		struct cifs_ace *pntace =
 			(struct cifs_ace *)((char *)pnndacl + size);
 
 		size += setup_special_mode_ACE(pntace, nmode);
 		num_aces++;
+		goto set_size;
 	}
 
+	/*
+	 * We'll try to keep the mode as requested by the user.
+	 * But in cases where we cannot meaningfully convert that
+	 * into ACL, return back the updated mode, so that it is
+	 * updated in the inode.
+	 */
+
+	if (!memcmp(pownersid, pgrpsid, sizeof(struct cifs_sid))) {
+		/*
+		 * Case when owner and group SIDs are the same.
+		 * Set the more restrictive of the two modes.
+		 */
+		user_mode = nmode & (nmode << 3) & 0700;
+		group_mode = nmode & (nmode >> 3) & 0070;
+	} else {
+		user_mode = nmode & 0700;
+		group_mode = nmode & 0070;
+	}
+
+	other_mode = nmode & 0007;
+
+	/* We need DENY ACE when the perm is more restrictive than the next sets. */
+	deny_user_mode = ~(user_mode) & ((group_mode << 3) | (other_mode << 6)) & 0700;
+	deny_group_mode = ~(group_mode) & (other_mode << 3) & 0070;
+
+	*pnmode = user_mode | group_mode | other_mode | (nmode & ~0777);
+
+	if (deny_user_mode) {
+		size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
+				pownersid, deny_user_mode, 0700, ACCESS_DENIED);
+		num_aces++;
+	}
+	/* Group DENY ACE does not conflict with owner ALLOW ACE. Keep in preferred order*/
+	if (deny_group_mode && !(deny_group_mode & (user_mode >> 3))) {
+		size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
+				pgrpsid, deny_group_mode, 0070, ACCESS_DENIED);
+		num_aces++;
+	}
 	size += fill_ace_for_sid((struct cifs_ace *) ((char *)pnndacl + size),
-					pownersid, nmode, S_IRWXU);
+			pownersid, user_mode, 0700, ACCESS_ALLOWED);
 	num_aces++;
+	/* Group DENY ACE conflicts with owner ALLOW ACE. So keep it after. */
+	if (deny_group_mode && (deny_group_mode & (user_mode >> 3))) {
+		size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
+				pgrpsid, deny_group_mode, 0070, ACCESS_DENIED);
+		num_aces++;
+	}
 	size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
-					pgrpsid, nmode, S_IRWXG);
+			pgrpsid, group_mode, 0070, ACCESS_ALLOWED);
 	num_aces++;
 	size += fill_ace_for_sid((struct cifs_ace *)((char *)pnndacl + size),
-					 &sid_everyone, nmode, S_IRWXO);
+			&sid_everyone, other_mode, 0007, ACCESS_ALLOWED);
 	num_aces++;
 
+set_size:
 	pndacl->num_aces = cpu_to_le32(num_aces);
 	pndacl->size = cpu_to_le16(size + sizeof(struct cifs_acl));
 
@@ -1000,7 +1074,7 @@ static int parse_sec_desc(struct cifs_sb_info *cifs_sb,
 
 /* Convert permission bits from mode to equivalent CIFS ACL */
 static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
-	__u32 secdesclen, __u64 nmode, kuid_t uid, kgid_t gid,
+	__u32 secdesclen, __u64 *pnmode, kuid_t uid, kgid_t gid,
 	bool mode_from_sid, bool id_from_sid, int *aclflag)
 {
 	int rc = 0;
@@ -1012,7 +1086,7 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
 	struct cifs_acl *dacl_ptr = NULL;  /* no need for SACL ptr */
 	struct cifs_acl *ndacl_ptr = NULL; /* no need for SACL ptr */
 
-	if (nmode != NO_CHANGE_64) { /* chmod */
+	if (pnmode && *pnmode != NO_CHANGE_64) { /* chmod */
 		owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
 				le32_to_cpu(pntsd->osidoffset));
 		group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
@@ -1026,7 +1100,7 @@ static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
 		ndacl_ptr->num_aces = 0;
 
 		rc = set_chmod_dacl(ndacl_ptr, owner_sid_ptr, group_sid_ptr,
-				    nmode, mode_from_sid);
+				    pnmode, mode_from_sid);
 		sidsoffset = ndacloffset + le16_to_cpu(ndacl_ptr->size);
 		/* copy sec desc control portion & owner and group sids */
 		copy_sec_desc(pntsd, pnntsd, sidsoffset);
@@ -1282,7 +1356,7 @@ cifs_acl_to_fattr(struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
 
 /* Convert mode bits to an ACL so we can update the ACL on the server */
 int
-id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 nmode,
+id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 *pnmode,
 			kuid_t uid, kgid_t gid)
 {
 	int rc = 0;
@@ -1341,7 +1415,7 @@ id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 nmode,
 	else
 		id_from_sid = false;
 
-	rc = build_sec_desc(pntsd, pnntsd, secdesclen, nmode, uid, gid,
+	rc = build_sec_desc(pntsd, pnntsd, secdesclen, pnmode, uid, gid,
 			    mode_from_sid, id_from_sid, &aclflag);
 
 	cifs_dbg(NOISY, "build_sec_desc rc: %d\n", rc);