Kernel - Fixed a possible infinite loop in VFS_ParsePath
[tpg/acess2.git] / Kernel / vfs / open.c
index 655272e..02c9266 100644 (file)
@@ -1,32 +1,30 @@
 /*
- * AcessMicro VFS
+ * Acess2 VFS
  * - Open, Close and ChDir
  */
 #define DEBUG  0
-#include <common.h>
+#include <acess.h>
 #include "vfs.h"
 #include "vfs_int.h"
 #include "vfs_ext.h"
 
 // === CONSTANTS ===
 #define        OPEN_MOUNT_ROOT 1
-#define MAX_KERNEL_FILES       128
 #define MAX_PATH_SLASHES       256
+#define MAX_NESTED_LINKS       4
+#define MAX_PATH_LEN   255
 
 // === IMPORTS ===
 extern tVFS_Node       gVFS_MemRoot;
 extern tVFS_Mount      *gVFS_RootMount;
-
-// === GLOBALS ===
-tVFS_Handle    *gaUserHandles = (void*)MM_PPD_VFS;
-tVFS_Handle    *gaKernelHandles = (void*)MM_KERNEL_VFS;
+extern int     VFS_AllocHandle(int bIsUser, tVFS_Node *Node, int Mode);
 
 // === CODE ===
 /**
- * \fn char *VFS_GetAbsPath(char *Path)
+ * \fn char *VFS_GetAbsPath(const char *Path)
  * \brief Create an absolute path from a relative one
  */
-char *VFS_GetAbsPath(char *Path)
+char *VFS_GetAbsPath(const char *Path)
 {
        char    *ret;
         int    pathLen = strlen(Path);
@@ -34,9 +32,9 @@ char *VFS_GetAbsPath(char *Path)
        char    *tmpStr;
        int             iPos = 0;
        int             iPos2 = 0;
-       char    *chroot = CFGPTR(CFG_VFS_CHROOT);
+       const char      *chroot = CFGPTR(CFG_VFS_CHROOT);
         int    chrootLen;
-       char    *cwd = CFGPTR(CFG_VFS_CWD);
+       const char      *cwd = CFGPTR(CFG_VFS_CWD);
         int    cwdLen;
        
        ENTER("sPath", Path);
@@ -45,7 +43,7 @@ char *VFS_GetAbsPath(char *Path)
        if(Path[0] == '$') {
                ret = malloc(strlen(Path)+1);
                if(!ret) {
-                       Warning("VFS_GetAbsPath - malloc() returned NULL");
+                       Log_Warning("VFS", "VFS_GetAbsPath: malloc() returned NULL");
                        return NULL;
                }
                strcpy(ret, Path);
@@ -65,7 +63,7 @@ char *VFS_GetAbsPath(char *Path)
        if(Path[0] == '/') {
                ret = malloc(pathLen + 1);
                if(!ret) {
-                       Warning("VFS_GetAbsPath - malloc() returned NULL");
+                       Log_Warning("VFS", "VFS_GetAbsPath: malloc() returned NULL");
                        return NULL;
                }
                strcpy(ret, Path);
@@ -82,7 +80,7 @@ char *VFS_GetAbsPath(char *Path)
                strcpy(ret, cwd);
                ret[cwdLen] = '/';
                strcpy(&ret[cwdLen+1], Path);
-               //Log("ret = '%s'\n", ret);
+               //Log("ret = '%s'", ret);
        }
        
        // Parse Path
@@ -166,17 +164,18 @@ char *VFS_GetAbsPath(char *Path)
 }
 
 /**
- * \fn char *VFS_ParsePath(char *Path, char **TruePath)
+ * \fn char *VFS_ParsePath(const char *Path, char **TruePath)
  * \brief Parses a path, resolving sysmlinks and applying permissions
  */
-tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
+tVFS_Node *VFS_ParsePath(const char *Path, char **TruePath)
 {
-       tVFS_Mount      *mnt;
-       tVFS_Mount      *longestMount = gVFS_RootMount; // Root is first
+       tVFS_Mount      *mnt, *longestMount;
         int    cmp, retLength = 0;
         int    ofs, nextSlash;
+        int    iNestedLinks = 0;
        tVFS_Node       *curNode, *tmpNode;
        char    *tmp;
+       char    path_buffer[MAX_PATH_LEN+1];
        
        ENTER("sPath pTruePath", Path, TruePath);
        
@@ -190,8 +189,9 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                LEAVE('p', curNode);
                return curNode;
        }
+
+restart_parse: 
        // For root we always fast return
-       
        if(Path[0] == '/' && Path[1] == '\0') {
                if(TruePath) {
                        *TruePath = malloc( gVFS_RootMount->MountPointLen+1 );
@@ -208,6 +208,7 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
        }
        
        // Find Mountpoint
+       longestMount = gVFS_RootMount;
        for(mnt = gVFS_Mounts;
                mnt;
                mnt = mnt->Next)
@@ -236,12 +237,6 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                longestMount = mnt;
        }
        
-       // Sanity Check
-       /*if(!longestMount) {
-               Log("VFS_ParsePath - ERROR: No Root Node\n");
-               return NULL;
-       }*/
-       
        // Save to shorter variable
        mnt = longestMount;
        
@@ -250,7 +245,8 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
        // Initialise String
        if(TruePath)
        {
-               *TruePath = malloc( mnt->MountPointLen+1 );
+               // Assumes that the resultant path (here) will not be > strlen(Path) + 1
+               *TruePath = malloc( strlen(Path) + 1 );
                strcpy(*TruePath, mnt->MountPoint);
                retLength = mnt->MountPointLen;
        }
@@ -259,17 +255,19 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
        curNode->ReferenceCount ++;     
        // Parse Path
        ofs = mnt->MountPointLen+1;
-       for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; Path[nextSlash]='/',ofs = nextSlash + 1)
+       for(; (nextSlash = strpos(&Path[ofs], '/')) != -1; ofs += nextSlash + 1)
        {
-               nextSlash += ofs;
-               Path[nextSlash] = '\0';
-       
-               // Check for empty string
-               if( Path[ofs] == '\0' ) continue;
+               char    pathEle[nextSlash+1];
+               
+               // Empty String
+               if(nextSlash == 0)      continue;
+               
+               memcpy(pathEle, &Path[ofs], nextSlash);
+               pathEle[nextSlash] = 0;
        
                // Check permissions on root of filesystem
                if( !VFS_CheckACL(curNode, VFS_PERM_EXECUTE) ) {
-                       curNode->Close( curNode );
+                       if(curNode->Close)      curNode->Close( curNode );
                        if(TruePath) {
                                free(*TruePath);
                                *TruePath = NULL;
@@ -280,34 +278,35 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                }
                
                // Check if the node has a FindDir method
-               if(!curNode->FindDir) {
+               if( !curNode->FindDir )
+               {
                        if(curNode->Close)      curNode->Close(curNode);
                        if(TruePath) {
                                free(*TruePath);
                                *TruePath = NULL;
                        }
-                       Path[nextSlash] = '/';
                        //Log("FindDir fail on '%s'", Path);
                        LEAVE('n');
                        return NULL;
                }
-               LOG("FindDir(%p, '%s')", curNode, &Path[ofs]);
+               LOG("FindDir{=%p}(%p, '%s')", curNode->FindDir, curNode, pathEle);
                // Get Child Node
-               tmpNode = curNode->FindDir(curNode, &Path[ofs]);
+               tmpNode = curNode->FindDir(curNode, pathEle);
                LOG("tmpNode = %p", tmpNode);
-               if(curNode->Close)
+               if(curNode->Close) {
+                       //LOG2("curNode->Close = %p", curNode->Close);
                        curNode->Close(curNode);
+               }
                curNode = tmpNode;
                
                // Error Check
                if(!curNode) {
-                       LOG("Node '%s' not found in dir '%s'", &Path[ofs], Path);
+                       LOG("Node '%s' not found in dir '%s'", pathEle, Path);
                        if(TruePath) {
                                free(*TruePath);
                                *TruePath = NULL;
                        }
-                       //Log("Child fail on '%s' ('%s)", Path, &Path[ofs]);
-                       Path[nextSlash] = '/';
+                       //Log("Child fail on '%s' ('%s)", Path, pathEle);
                        LEAVE('n');
                        return NULL;
                }
@@ -318,30 +317,43 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                                free(*TruePath);
                                *TruePath = NULL;
                        }
-                       tmp = malloc( curNode->Size + 1 );
-                       curNode->Read( curNode, 0, curNode->Size, tmp );
-                       tmp[ curNode->Size ] = '\0';
-                       
-                       // Parse Symlink Path
-                       curNode = VFS_ParsePath(tmp, TruePath);
+                       if(!curNode->Read) {
+                               Warning("VFS_ParsePath - Read of node %p is NULL (%s)",
+                                       curNode, Path);
+                               if(curNode->Close)      curNode->Close(curNode);
+                               // No need to free *TruePath, it should already be NULL
+                               LEAVE('n');
+                               return NULL;
+                       }
                        
-                       // Error Check
-                       if(!curNode) {
-                               Log("Symlink fail '%s'", tmp);
-                               free(tmp);      // Free temp string
+                       if(iNestedLinks > MAX_NESTED_LINKS) {
+                               if(curNode->Close)      curNode->Close(curNode);
                                LEAVE('n');
                                return NULL;
                        }
                        
-                       // Set Path Variable
-                       if(TruePath) {
-                               *TruePath = tmp;
-                               retLength = strlen(tmp);
-                       } else {
-                               free(tmp);      // Free temp string
+                       // Parse Symlink Path
+                       // - Just update the path variable and restart the function
+                       // > Count nested symlinks and limit to some value (counteracts loops)
+                       {
+                                int    remlen = strlen(Path) - (ofs + nextSlash);
+                               if( curNode->Size + remlen > MAX_PATH_LEN ) {
+                                       if(curNode->Close)      curNode->Close(curNode);
+                                       Log_Warning("VFS", "VFS_ParsePath - Symlinked path too long");
+                                       LEAVE('n');
+                                       return NULL;
+                               }
+                               curNode->Read( curNode, 0, curNode->Size, path_buffer );
+                               path_buffer[ curNode->Size ] = '\0';
+                               strcat(path_buffer, &Path[ofs+nextSlash]);
+                               
+                               Path = path_buffer;
+                               iNestedLinks ++;
                        }
                        
-                       continue;
+
+                       // EVIL: Goto :)
+                       goto restart_parse;
                }
                
                // Handle Non-Directories
@@ -357,11 +369,12 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                if(!TruePath)   continue;
                
                // Increase buffer space
-               tmp = realloc( *TruePath, retLength + strlen(&Path[ofs]) + 1 + 1 );
+               tmp = realloc( *TruePath, retLength + strlen(pathEle) + 1 + 1 );
                // Check if allocation succeeded
                if(!tmp) {
                        Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
                        free(*TruePath);
+                       *TruePath = NULL;
                        if(curNode->Close)      curNode->Close(curNode);
                        LEAVE('n');
                        return NULL;
@@ -369,9 +382,23 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                *TruePath = tmp;
                // Append to path
                (*TruePath)[retLength] = '/';
-               strcpy(*TruePath+retLength+1, &Path[ofs]);
+               strcpy(*TruePath+retLength+1, pathEle);
+               
+               LOG("*TruePath = '%s'", *TruePath);
+               
                // - Extend Path
-               retLength += strlen(&Path[ofs])+1;
+               retLength += nextSlash + 1;
+       }
+       
+       if( !curNode->FindDir ) {
+               if(curNode->Close)      curNode->Close(curNode);
+               if(TruePath) {
+                       free(*TruePath);
+                       *TruePath = NULL;
+               }
+               Log("FindDir fail on '%s'", Path);
+               LEAVE('n');
+               return NULL;
        }
        
        // Get last node
@@ -395,7 +422,7 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
                tmp = realloc(*TruePath, retLength + strlen(&Path[ofs]) + 1 + 1);
                // Check if allocation succeeded
                if(!tmp) {
-                       Warning("VFS_ParsePath -  Unable to reallocate true path buffer");
+                       Log_Warning("VFS", "VFS_ParsePath -  Unable to reallocate true path buffer");
                        free(*TruePath);
                        if(tmpNode->Close)      tmpNode->Close(curNode);
                        LEAVE('n');
@@ -414,10 +441,10 @@ tVFS_Node *VFS_ParsePath(char *Path, char **TruePath)
 }
 
 /**
- * \fn int VFS_Open(char *Path, Uint Mode)
+ * \fn int VFS_Open(const char *Path, Uint Mode)
  * \brief Open a file
  */
-int VFS_Open(char *Path, Uint Mode)
+int VFS_Open(const char *Path, Uint Mode)
 {
        tVFS_Node       *node;
        char    *absPath;
@@ -427,6 +454,10 @@ int VFS_Open(char *Path, Uint Mode)
        
        // Get absolute path
        absPath = VFS_GetAbsPath(Path);
+       if(absPath == NULL) {
+               Log_Warning("VFS", "VFS_Open: Path expansion failed '%s'", Path);
+               return -1;
+       }
        LOG("absPath = \"%s\"", absPath);
        // Parse path and get mount point
        node = VFS_ParsePath(absPath, NULL);
@@ -471,56 +502,16 @@ int VFS_Open(char *Path, Uint Mode)
        
        // Permissions Check
        if( !VFS_CheckACL(node, i) ) {
-               node->Close( node );
+               if(node->Close) node->Close( node );
                Log("VFS_Open: Permissions Failed");
                LEAVE('i', -1);
                return -1;
        }
        
-       // Check for a user open
-       if(Mode & VFS_OPENFLAG_USER)
-       {
-               // Allocate Buffer
-               if( MM_GetPhysAddr( (Uint)gaUserHandles ) == 0 )
-               {
-                       Uint    addr, size;
-                       size = CFGINT(CFG_VFS_MAXFILES) * sizeof(tVFS_Handle);
-                       for(addr = 0; addr < size; addr += 0x1000)
-                               MM_Allocate( (Uint)gaUserHandles + addr );
-                       memset( gaUserHandles, 0, size );
-               }
-               // Get a handle
-               for(i=0;i<CFGINT(CFG_VFS_MAXFILES);i++)
-               {
-                       if(gaUserHandles[i].Node)       continue;
-                       gaUserHandles[i].Node = node;
-                       gaUserHandles[i].Position = 0;
-                       gaUserHandles[i].Mode = Mode;
-                       LEAVE('i', i);
-                       return i;
-               }
-       }
-       else
-       {
-               // Allocate space if not already
-               if( MM_GetPhysAddr( (Uint)gaKernelHandles ) == 0 )
-               {
-                       Uint    addr, size;
-                       size = MAX_KERNEL_FILES * sizeof(tVFS_Handle);
-                       for(addr = 0; addr < size; addr += 0x1000)
-                               MM_Allocate( (Uint)gaKernelHandles + addr );
-                       memset( gaKernelHandles, 0, size );
-               }
-               // Get a handle
-               for(i=0;i<MAX_KERNEL_FILES;i++)
-               {
-                       if(gaKernelHandles[i].Node)     continue;
-                       gaKernelHandles[i].Node = node;
-                       gaKernelHandles[i].Position = 0;
-                       gaKernelHandles[i].Mode = Mode;
-                       LEAVE('x', i|VFS_KERNEL_FLAG);
-                       return i|VFS_KERNEL_FLAG;
-               }
+       i = VFS_AllocHandle( !!(Mode & VFS_OPENFLAG_USER), node, Mode );
+       if( i >= 0 ) {
+               LEAVE('x', i);
+               return i;
        }
        
        Log("VFS_Open: Out of handles");
@@ -528,6 +519,67 @@ int VFS_Open(char *Path, Uint Mode)
        return -1;
 }
 
+
+/**
+ * \brief Open a file from an open directory
+ */
+int VFS_OpenChild(Uint *Errno, int FD, const char *Name, Uint Mode)
+{
+       tVFS_Handle     *h;
+       tVFS_Node       *node;
+        int    i;
+       
+       // Get handle
+       h = VFS_GetHandle(FD);
+       if(h == NULL) {
+               Log_Warning("VFS", "VFS_OpenChild - Invalid file handle 0x%x", FD);
+               if(Errno)       *Errno = EINVAL;
+               LEAVE('i', -1);
+               return -1;
+       }
+       
+       // Check for directory
+       if( !(h->Node->Flags & VFS_FFLAG_DIRECTORY) ) {
+               Log_Warning("VFS", "VFS_OpenChild - Passed handle is not a directory", FD);
+               if(Errno)       *Errno = ENOTDIR;
+               LEAVE('i', -1);
+               return -1;
+       }
+       
+       // Find Child
+       node = h->Node->FindDir(h->Node, Name);
+       if(!node) {
+               if(Errno)       *Errno = ENOENT;
+               LEAVE('i', -1);
+               return -1;
+       }
+       
+       i = 0;
+       i |= (Mode & VFS_OPENFLAG_EXEC) ? VFS_PERM_EXECUTE : 0;
+       i |= (Mode & VFS_OPENFLAG_READ) ? VFS_PERM_READ : 0;
+       i |= (Mode & VFS_OPENFLAG_WRITE) ? VFS_PERM_WRITE : 0;
+       
+       // Permissions Check
+       if( !VFS_CheckACL(node, i) ) {
+               if(node->Close) node->Close( node );
+               Log_Notice("VFS", "VFS_OpenChild - Permissions Failed");
+               if(Errno)       *Errno = EACCES;
+               LEAVE('i', -1);
+               return -1;
+       }
+       
+       i = VFS_AllocHandle( !!(Mode & VFS_OPENFLAG_USER), node, Mode );
+       if( i >= 0 ) {
+               LEAVE('x', i);
+               return i;
+       }
+       
+       Log_Error("VFS", "VFS_OpenChild - Out of handles");
+       if(Errno)       *Errno = ENFILE;
+       LEAVE('i', -1);
+       return -1;
+}
+
 /**
  * \fn void VFS_Close(int FD)
  * \brief Closes an open file handle
@@ -539,10 +591,18 @@ void VFS_Close(int FD)
        // Get handle
        h = VFS_GetHandle(FD);
        if(h == NULL) {
-               Warning("Invalid file handle passed to VFS_Close, 0x%x\n", FD);
+               Log_Warning("VFS", "Invalid file handle passed to VFS_Close, 0x%x", FD);
                return;
        }
        
+       #if VALIDATE_VFS_FUNCTIPONS
+       if(h->Node->Close && !MM_GetPhysAddr(h->Node->Close)) {
+               Log_Warning("VFS", "Node %p's ->Close method is invalid (%p)",
+                       h->Node, h->Node->Close);
+               return ;
+       }
+       #endif
+       
        if(h->Node->Close)
                h->Node->Close( h->Node );
        
@@ -552,7 +612,7 @@ void VFS_Close(int FD)
 /**
  * \brief Change current working directory
  */
-int VFS_ChDir(char *Dest)
+int VFS_ChDir(const char *Dest)
 {
        char    *buf;
         int    fd;
@@ -598,7 +658,7 @@ int VFS_ChDir(char *Dest)
  * \fn int VFS_ChRoot(char *New)
  * \brief Change current root directory
  */
-int VFS_ChRoot(char *New)
+int VFS_ChRoot(const char *New)
 {
        char    *buf;
         int    fd;
@@ -643,29 +703,6 @@ int VFS_ChRoot(char *New)
        return 1;
 }
 
-/**
- * \fn tVFS_Handle *VFS_GetHandle(int FD)
- * \brief Gets a pointer to the handle information structure
- */
-tVFS_Handle *VFS_GetHandle(int FD)
-{
-       tVFS_Handle     *h;
-       
-       if(FD < 0)      return NULL;
-       
-       if(FD & VFS_KERNEL_FLAG) {
-               FD &= (VFS_KERNEL_FLAG - 1);
-               if(FD >= MAX_KERNEL_FILES)      return NULL;
-               h = &gaKernelHandles[ FD ];
-       } else {
-               if(FD >= CFGINT(CFG_VFS_MAXFILES))      return NULL;
-               h = &gaUserHandles[ FD ];
-       }
-       
-       if(h->Node == NULL)     return NULL;
-       return h;
-}
-
 // === EXPORTS ===
 EXPORT(VFS_Open);
 EXPORT(VFS_Close);

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