1 files changed, 71 insertions, 58 deletions

diff --git a/security/commoncap.c b/security/commoncap.c
index f88119c..d7eff57 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -202,17 +202,70 @@ int cap_inode_killpriv(struct dentry *dentry)
 	return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
 }
 
-static inline int cap_from_disk(struct vfs_cap_data *caps,
-				struct linux_binprm *bprm, unsigned size)
+static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
+					  struct linux_binprm *bprm)
 {
+	unsigned i;
+	int ret = 0;
+
+	if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE)
+		bprm->cap_effective = true;
+	else
+		bprm->cap_effective = false;
+
+	CAP_FOR_EACH_U32(i) {
+		__u32 permitted = caps->permitted.cap[i];
+		__u32 inheritable = caps->inheritable.cap[i];
+
+		/*
+		 * pP' = (X & fP) | (pI & fI)
+		 */
+		bprm->cap_post_exec_permitted.cap[i] =
+			(current->cap_bset.cap[i] & permitted) |
+			(current->cap_inheritable.cap[i] & inheritable);
+
+		if (permitted & ~bprm->cap_post_exec_permitted.cap[i]) {
+			/*
+			 * insufficient to execute correctly
+			 */
+			ret = -EPERM;
+		}
+	}
+
+	/*
+	 * For legacy apps, with no internal support for recognizing they
+	 * do not have enough capabilities, we return an error if they are
+	 * missing some "forced" (aka file-permitted) capabilities.
+	 */
+	return bprm->cap_effective ? ret : 0;
+}
+
+int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
+{
+	struct inode *inode = dentry->d_inode;
 	__u32 magic_etc;
 	unsigned tocopy, i;
-	int ret;
+	int size;
+	struct vfs_cap_data caps;
+
+	memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
+
+	if (!inode || !inode->i_op || !inode->i_op->getxattr)
+		return -ENODATA;
+
+	size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps,
+				   XATTR_CAPS_SZ);
+	if (size == -ENODATA || size == -EOPNOTSUPP) {
+		/* no data, that's ok */
+		return -ENODATA;
+	}
+	if (size < 0)
+		return size;
 
 	if (size < sizeof(magic_etc))
 		return -EINVAL;
 
-	magic_etc = le32_to_cpu(caps->magic_etc);
+	cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc);
 
 	switch ((magic_etc & VFS_CAP_REVISION_MASK)) {
 	case VFS_CAP_REVISION_1:
@@ -229,46 +282,13 @@ static inline int cap_from_disk(struct vfs_cap_data *caps,
 		return -EINVAL;
 	}
 
-	if (magic_etc & VFS_CAP_FLAGS_EFFECTIVE) {
-		bprm->cap_effective = true;
-	} else {
-		bprm->cap_effective = false;
-	}
-
-	ret = 0;
-
 	CAP_FOR_EACH_U32(i) {
-		__u32 value_cpu;
-
-		if (i >= tocopy) {
-			/*
-			 * Legacy capability sets have no upper bits
-			 */
-			bprm->cap_post_exec_permitted.cap[i] = 0;
-			continue;
-		}
-		/*
-		 * pP' = (X & fP) | (pI & fI)
-		 */
-		value_cpu = le32_to_cpu(caps->data[i].permitted);
-		bprm->cap_post_exec_permitted.cap[i] =
-			(current->cap_bset.cap[i] & value_cpu) |
-			(current->cap_inheritable.cap[i] &
-				le32_to_cpu(caps->data[i].inheritable));
-		if (value_cpu & ~bprm->cap_post_exec_permitted.cap[i]) {
-			/*
-			 * insufficient to execute correctly
-			 */
-			ret = -EPERM;
-		}
+		if (i >= tocopy)
+			break;
+		cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted);
+		cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable);
 	}
-
-	/*
-	 * For legacy apps, with no internal support for recognizing they
-	 * do not have enough capabilities, we return an error if they are
-	 * missing some "forced" (aka file-permitted) capabilities.
-	 */
-	return bprm->cap_effective ? ret : 0;
+	return 0;
 }
 
 /* Locate any VFS capabilities: */
@@ -276,8 +296,7 @@ static int get_file_caps(struct linux_binprm *bprm)
 {
 	struct dentry *dentry;
 	int rc = 0;
-	struct vfs_cap_data vcaps;
-	struct inode *inode;
+	struct cpu_vfs_cap_data vcaps;
 
 	bprm_clear_caps(bprm);
 
@@ -288,24 +307,18 @@ static int get_file_caps(struct linux_binprm *bprm)
 		return 0;
 
 	dentry = dget(bprm->file->f_dentry);
-	inode = dentry->d_inode;
-	if (!inode->i_op || !inode->i_op->getxattr)
-		goto out;
 
-	rc = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, &vcaps,
-				   XATTR_CAPS_SZ);
-	if (rc == -ENODATA || rc == -EOPNOTSUPP) {
-		/* no data, that's ok */
-		rc = 0;
+	rc = get_vfs_caps_from_disk(dentry, &vcaps);
+	if (rc < 0) {
+		if (rc == -EINVAL)
+			printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n",
+				__func__, rc, bprm->filename);
+		else if (rc == -ENODATA)
+			rc = 0;
 		goto out;
 	}
-	if (rc < 0)
-		goto out;
 
-	rc = cap_from_disk(&vcaps, bprm, rc);
-	if (rc == -EINVAL)
-		printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n",
-		       __func__, rc, bprm->filename);
+	rc = bprm_caps_from_vfs_caps(&vcaps, bprm);
 
 out:
 	dput(dentry);