ar: hopefully fix out-of-bounds read in get_header_ar()
[oweals/busybox.git] / archival / ar.c
index 61ce830293131aab876dc5d43a695211af5c08cc..f4edeb087c2cf7aa8661d06687e58aadb4170b07 100644 (file)
 /* vi: set sw=4 ts=4: */
 /*
- * Mini ar implementation for busybox 
+ * Mini ar implementation for busybox
  *
  * Copyright (C) 2000 by Glenn McGrath
- * Written by Glenn McGrath <bug1@netconnect.com.au> 1 June 2000
- *             
- * Based in part on BusyBox tar, Debian dpkg-deb and GNU ar.
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * Based in part on BusyBox tar, Debian dpkg-deb and GNU ar.
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Archive creation support:
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Written by Alexander Shishkin.
  *
- * Last modified 9 September 2000
+ * There is no single standard to adhere to so ar may not portable
+ * between different systems
+ * http://www.unix-systems.org/single_unix_specification_v2/xcu/ar.html
  */
-#include <stdio.h>
-#include <string.h>
-#include <fcntl.h>
-#include <errno.h>
-#include <ctype.h>
-#include <time.h>
-#include <utime.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <malloc.h>
-#include "internal.h"
-
-#define BLOCK_SIZE 60
-#define PRESERVE_DATE 1        /* preserve original dates */
-#define VERBOSE       2        /* be verbose */
-#define DISPLAY       4        /* display contents */
-#define EXT_TO_FILE   8        /* extract contents of archive */
-#define EXT_TO_STDOUT 16       /* extract to stdout */
-#define RECURSIVE     32        
-
-#define MAX_NAME_LENGTH 100
-
-//#define BB_DECLARE_EXTERN
-//#define bb_need_io_error
-//#include "messages.c"
-
-typedef struct rawArHeader {    /* Byte Offset */
-        char name[16];          /*  0-15 */
-        char date[12];          /* 16-27 */
-        char uid[6], gid[6];    /* 28-39 */
-        char mode[8];           /* 40-47 */
-        char size[10];          /* 48-57 */
-        char fmag[2];           /* 58-59 */
-} rawArHeader_t;
-
-typedef struct headerL {
-       char name[MAX_NAME_LENGTH];
-        size_t size;
-        uid_t uid;
-        gid_t gid;
-        mode_t mode;
-        time_t mtime;
-        off_t offset;
-       struct headerL *next;
-} headerL_t;
+//config:config AR
+//config:      bool "ar (9.5 kb)"
+//config:      default n  # needs to be improved to be able to replace binutils ar
+//config:      help
+//config:      ar is an archival utility program used to create, modify, and
+//config:      extract contents from archives. In practice, it is used exclusively
+//config:      for object module archives used by compilers.
+//config:
+//config:      Unless you have a specific application which requires ar, you should
+//config:      probably say N here: most compilers come with their own ar utility.
+//config:
+//config:config FEATURE_AR_LONG_FILENAMES
+//config:      bool "Support long filenames (not needed for debs)"
+//config:      default y
+//config:      depends on AR
+//config:      help
+//config:      By default the ar format can only store the first 15 characters
+//config:      of the filename, this option removes that limitation.
+//config:      It supports the GNU ar long filename method which moves multiple long
+//config:      filenames into a the data section of a new ar entry.
+//config:
+//config:config FEATURE_AR_CREATE
+//config:      bool "Support archive creation"
+//config:      default y
+//config:      depends on AR
+//config:      help
+//config:      This enables archive creation (-c and -r) with busybox ar.
 
-/*
- * identify Ar header (magic) and set srcFd to first header entry 
- */
-static int checkArMagic(int srcFd)
+//applet:IF_AR(APPLET(ar, BB_DIR_USR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_AR) += ar.o
+
+//usage:#define ar_trivial_usage
+//usage:       "[-o] [-v] [-p] [-t] [-x] ARCHIVE FILES"
+//usage:#define ar_full_usage "\n\n"
+//usage:       "Extract or list FILES from an ar archive\n"
+//usage:     "\n       -o      Preserve original dates"
+//usage:     "\n       -p      Extract to stdout"
+//usage:     "\n       -t      List"
+//usage:     "\n       -x      Extract"
+//usage:     "\n       -v      Verbose"
+
+#include "libbb.h"
+#include "bb_archive.h"
+#include "ar.h"
+
+#if ENABLE_FEATURE_AR_CREATE
+/* filter out entries with same names as specified on the command line */
+static char FAST_FUNC filter_replaceable(archive_handle_t *handle)
 {
-        char arMagic[8];
-        if (fullRead(srcFd, arMagic, 8) != 8)
-                return (FALSE);
-        
-       if (strncmp(arMagic,"!<arch>",7) != 0)
-                return(FALSE);
-       return(TRUE);
+       if (find_list_entry(handle->accept, handle->file_header->name))
+               return EXIT_FAILURE;
+
+       return EXIT_SUCCESS;
 }
 
-/*
- * read, convert and check the raw ar header
- * srcFd should be pointing to the start of header prior to entry
- * srcFd will be pointing at the start of data after successful exit
- * if returns FALSE srcFd is reset to initial position
- */
-static int readRawArHeader(int srcFd, headerL_t *header)
+static void output_ar_header(archive_handle_t *handle)
 {
-       rawArHeader_t rawArHeader;
-       off_t   initialOffset;
-       size_t nameLength;
-       
-       initialOffset = lseek(srcFd, 0, SEEK_CUR);
-       if (fullRead(srcFd, (char *) &rawArHeader, 60) != 60) {
-               lseek(srcFd, initialOffset, SEEK_SET);
-               return(FALSE);
+       /* GNU ar 2.19.51.0.14 creates malformed archives
+        * if input files are >10G. It also truncates files >4GB
+        * (uses "size mod 4G"). We abort in this case:
+        * We could add support for up to 10G files, but this is unlikely to be useful.
+        * Note that unpacking side limits all fields to "unsigned int" data type,
+        * and treats "all ones" as an error indicator. Thus max we allow here is UINT_MAX-1.
+        */
+       enum {
+               /* for 2nd field: mtime */
+               MAX11CHARS = UINT_MAX > 0xffffffff ? (unsigned)99999999999 : UINT_MAX-1,
+               /* for last field: filesize */
+               MAX10CHARS = UINT_MAX > 0xffffffff ? (unsigned)9999999999 : UINT_MAX-1,
+       };
+
+       struct file_header_t *fh = handle->file_header;
+
+       if (handle->offset & 1) {
+               xwrite(handle->src_fd, "\n", 1);
+               handle->offset++;
        }
-       if ((rawArHeader.fmag[0]!='`') || (rawArHeader.fmag[1]!='\n')) {
-               lseek(srcFd, initialOffset, SEEK_SET);
-               return(FALSE);
+
+       /* Careful! The widths should be exact. Fields must be separated */
+       if (sizeof(off_t) > 4 && fh->size > (off_t)MAX10CHARS) {
+               bb_error_msg_and_die("'%s' is bigger than ar can handle", fh->name);
        }
+       fdprintf(handle->src_fd, "%-16.16s%-12lu%-6u%-6u%-8o%-10"OFF_FMT"u`\n",
+                       fh->name,
+                       (sizeof(time_t) > 4 && fh->mtime > MAX11CHARS) ? (long)0 : (long)fh->mtime,
+                       fh->uid > 99999 ? 0 : (int)fh->uid,
+                       fh->gid > 99999 ? 0 : (int)fh->gid,
+                       (int)fh->mode & 07777777,
+                       fh->size
+       );
 
-       strncpy(header->name, rawArHeader.name, 16);
-       nameLength=strcspn(header->name, " \\");
-       header->name[nameLength]='\0';
-       parse_mode(rawArHeader.mode, &header->mode);
-        header->mtime = atoi(rawArHeader.date);
-        header->uid = atoi(rawArHeader.uid);
-        header->gid = atoi(rawArHeader.gid);
-        header->size = (size_t) atoi(rawArHeader.size);
-        header->offset = initialOffset + (off_t) 60;
-       return(TRUE); 
+       handle->offset += AR_HEADER_LEN;
 }
 
 /*
- * get, check and correct the converted header
- */ 
-static int readArEntry(int srcFd, headerL_t *newEntry)
+ * when replacing files in an existing archive, copy from the
+ * original archive those files that are to be left intact
+ */
+static void FAST_FUNC copy_data(archive_handle_t *handle)
 {
-       size_t nameLength;
-
-       if(readRawArHeader(srcFd, newEntry)==FALSE)
-               return(FALSE);
-       
-       nameLength = strcspn(newEntry->name, "/");
-       
-       /* handle GNU style short filenames, strip trailing '/' */
-       if (nameLength > 0)
-               newEntry->name[nameLength]='\0';
-       
-       /* handle GNU style long filenames */ 
-       if (nameLength == 0) {
-               /* escape from recursive call */
-               if (newEntry->name[1]=='0') 
-                       return(TRUE);
-
-               /* the data section contains the real filename */
-               if (newEntry->name[1]=='/') {
-                       char tempName[MAX_NAME_LENGTH];
-
-                       if (newEntry->size > MAX_NAME_LENGTH)
-                               newEntry->size = MAX_NAME_LENGTH;
-                       fullRead(srcFd, tempName, newEntry->size);
-                       tempName[newEntry->size-3]='\0';
-                       
-                       /* read the second header for this entry */
-                       /* be carefull, this is recursive */
-                       if (readArEntry(srcFd, newEntry)==FALSE)
-                               return(FALSE);
-               
-                       if ((newEntry->name[0]='/') && (newEntry->name[1]='0'))
-                               strcpy(newEntry->name, tempName);
-                       else {
-                               errorMsg("Invalid long filename\n");
-                               return(FALSE);
-                       }
-               }
-       }
-       return(TRUE);   
+       archive_handle_t *out_handle = handle->ar__out;
+       struct file_header_t *fh = handle->file_header;
+
+       out_handle->file_header = fh;
+       output_ar_header(out_handle);
+
+       bb_copyfd_exact_size(handle->src_fd, out_handle->src_fd, fh->size);
+       out_handle->offset += fh->size;
 }
 
-/*
- * return the headerL_t struct for the specified filename
- */
-static headerL_t *getHeaders(int srcFd, headerL_t *head, int funct)
+static int write_ar_header(archive_handle_t *handle)
 {
-       headerL_t *list;
-        list = (headerL_t *) malloc(sizeof(headerL_t));
-
-        if (checkArMagic(srcFd)==TRUE) {
-               while(readArEntry(srcFd, list) == TRUE) {
-                       list->next = (headerL_t *) malloc(sizeof(headerL_t));
-                       *list->next = *head;
-                       *head = *list;
-               
-                       /* recursive check for sub-archives */
-                       if ( funct & RECURSIVE ) 
-                               head = getHeaders(srcFd, head, funct);
-                       lseek(srcFd, head->offset + head->size, SEEK_SET);
-               }
-       }
-        return(head);
+       char *fn;
+       char fn_h[17]; /* 15 + "/" + NUL */
+       struct stat st;
+       int fd;
+
+       fn = llist_pop(&handle->accept);
+       if (!fn)
+               return -1;
+
+       xstat(fn, &st);
+
+       handle->file_header->mtime = st.st_mtime;
+       handle->file_header->uid = st.st_uid;
+       handle->file_header->gid = st.st_gid;
+       handle->file_header->mode = st.st_mode;
+       handle->file_header->size = st.st_size;
+       handle->file_header->name = fn_h;
+//TODO: if ENABLE_FEATURE_AR_LONG_FILENAMES...
+       sprintf(fn_h, "%.15s/", bb_basename(fn));
+
+       output_ar_header(handle);
+
+       fd = xopen(fn, O_RDONLY);
+       bb_copyfd_exact_size(fd, handle->src_fd, st.st_size);
+       close(fd);
+       handle->offset += st.st_size;
+
+       return 0;
 }
 
-/*
- * find an entry in the linked list matching the filename
- */
-static headerL_t *findEntry(headerL_t *head, const char *filename)
+static int write_ar_archive(archive_handle_t *handle)
 {
-       while(head->next != NULL) {
-               if (strcmp(filename, head->name)==0) 
-                       return(head);
-               head=head->next;
+       struct stat st;
+       archive_handle_t *out_handle;
+
+       xfstat(handle->src_fd, &st, handle->ar__name);
+
+       /* if archive exists, create a new handle for output.
+        * we create it in place of the old one.
+        */
+       if (st.st_size != 0) {
+               out_handle = init_handle();
+               xunlink(handle->ar__name);
+               out_handle->src_fd = xopen(handle->ar__name, O_WRONLY | O_CREAT | O_TRUNC);
+               out_handle->accept = handle->accept;
+       } else {
+               out_handle = handle;
        }
-       return(NULL);
-}
 
-/*
- * populate linked list with all ar file entries and offset 
- */
-static int displayEntry(headerL_t *head, int funct)
-{
-       if ( funct & VERBOSE ) {
-               printf("%s %d/%d %8d %s ", modeString(head->mode), head->uid, head->gid, head->size, timeString(head->mtime));
+       handle->ar__out = out_handle;
+
+       xwrite(out_handle->src_fd, AR_MAGIC "\n", AR_MAGIC_LEN + 1);
+       out_handle->offset += AR_MAGIC_LEN + 1;
+
+       /* skip to the end of the archive if we have to append stuff */
+       if (st.st_size != 0) {
+               handle->filter = filter_replaceable;
+               handle->action_data = copy_data;
+               unpack_ar_archive(handle);
        }
-       printf("%s\n", head->name);
-       head = head->next;
-       return(TRUE);
+
+       while (write_ar_header(out_handle) == 0)
+               continue;
+
+       /* optional, since we exit right after we return */
+       if (ENABLE_FEATURE_CLEAN_UP) {
+               close(handle->src_fd);
+               if (out_handle->src_fd != handle->src_fd)
+                       close(out_handle->src_fd);
+       }
+
+       return EXIT_SUCCESS;
 }
+#endif /* FEATURE_AR_CREATE */
 
-static int extractAr(int srcFd, int dstFd, headerL_t *file)
+static void FAST_FUNC header_verbose_list_ar(const file_header_t *file_header)
 {
-       lseek(srcFd, file->offset, SEEK_SET);
-       if (copySubFile(srcFd, dstFd, (size_t) file->size) == TRUE)
-               return(TRUE);   
-       return(FALSE);
+       const char *mode = bb_mode_string(file_header->mode);
+       char *mtime;
+
+       mtime = ctime(&file_header->mtime);
+       mtime[16] = ' ';
+       memmove(&mtime[17], &mtime[20], 4);
+       mtime[21] = '\0';
+       printf("%s %u/%u%7"OFF_FMT"u %s %s\n", &mode[1],
+                       (int)file_header->uid, (int)file_header->gid,
+                       file_header->size,
+                       &mtime[4], file_header->name
+       );
 }
 
-extern int ar_main(int argc, char **argv)
+#define AR_OPT_VERBOSE          (1 << 0)
+#define AR_OPT_PRESERVE_DATE    (1 << 1)
+/* "ar r" implies create, but warns about it. c suppresses warning.
+ * bbox accepts but ignores it: */
+#define AR_OPT_CREATE           (1 << 2)
+
+#define AR_CMD_PRINT            (1 << 3)
+#define FIRST_CMD               AR_CMD_PRINT
+#define AR_CMD_LIST             (1 << 4)
+#define AR_CMD_EXTRACT          (1 << 5)
+#define AR_CMD_INSERT           (1 << 6)
+
+int ar_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int ar_main(int argc UNUSED_PARAM, char **argv)
 {
-        int funct = 0, opt=0;
-       int srcFd=0, dstFd=0;
-       headerL_t *header, *entry, *extractList;
-
-       while ((opt = getopt(argc, argv, "ovtpxR")) != -1) {
-               switch (opt) {
-               case 'o':
-                       funct |= PRESERVE_DATE;
-                       break;
-               case 'v':
-                       funct |= VERBOSE;
-                       break;
-               case 't':
-                       funct |= DISPLAY;
-                       break;
-               case 'x':
-                       funct |= EXT_TO_FILE;
-                       break;
-               case 'p':
-                       funct |= EXT_TO_STDOUT;
-                       break;
-               case 'R':
-                       funct |= RECURSIVE;
-                       break;
-               default:
-                       usage(ar_usage);
-               }
+       archive_handle_t *archive_handle;
+       unsigned opt, t;
+
+       archive_handle = init_handle();
+
+       /* prepend '-' to the first argument if required */
+       if (argv[1] && argv[1][0] != '-' && argv[1][0] != '\0')
+               argv[1] = xasprintf("-%s", argv[1]);
+       opt = getopt32(argv, "^"
+               "voc""ptx"IF_FEATURE_AR_CREATE("r")
+               "\0"
+               /* -1: at least one arg is reqd */
+               /* one of p,t,x[,r] is required */
+               "-1:p:t:x"IF_FEATURE_AR_CREATE(":r")
+       );
+       argv += optind;
+
+       t = opt / FIRST_CMD;
+       if (t & (t-1)) /* more than one of p,t,x[,r] are specified */
+               bb_show_usage();
+
+       if (opt & AR_CMD_PRINT) {
+               archive_handle->action_data = data_extract_to_stdout;
+       }
+       if (opt & AR_CMD_LIST) {
+               archive_handle->action_header = header_list;
        }
-        /* check the src filename was specified */
-       if (optind == argc) {
-                usage(ar_usage);
-                return(FALSE);
-        }
-       
-        if ( (srcFd = open(argv[optind], O_RDONLY)) < 0) {
-               errorMsg("Cannot read %s\n", optarg);
-                return (FALSE);
-        }
-       optind++;       
-       entry = (headerL_t *) malloc(sizeof(headerL_t));
-       header = (headerL_t *) malloc(sizeof(headerL_t));
-       extractList = (headerL_t *) malloc(sizeof(headerL_t));  
-
-       header = getHeaders(srcFd, header, funct);
-       
-       /* find files to extract or display */
-       if (optind<argc) {
-               /* only handle specified files */
-               while(optind < argc) { 
-                       if ( (entry = findEntry(header, argv[optind])) != NULL) {
-                               entry->next = (headerL_t *) malloc(sizeof(headerL_t));
-                               *entry->next = *extractList;
-                               *extractList = *entry;
-                       }
-                       optind++;
-               }       
+       if (opt & AR_CMD_EXTRACT) {
+               archive_handle->action_data = data_extract_all;
        }
-       else 
-               /* extract everything */
-               extractList = header;
-       
-       while(extractList->next != NULL) {      
-               if ( funct & EXT_TO_FILE ) {
-                       dstFd = open(extractList->name, O_WRONLY | O_CREAT, extractList->mode);
-                       
-                       extractAr(srcFd, dstFd, extractList);
-               }
-               if ( funct & EXT_TO_STDOUT )    
-                       extractAr(srcFd, fileno(stdout), extractList);  
-               if ( (funct & DISPLAY) || (funct & VERBOSE))
-                       displayEntry(extractList, funct);
-               extractList=extractList->next;
+       if (opt & AR_OPT_PRESERVE_DATE) {
+               archive_handle->ah_flags |= ARCHIVE_RESTORE_DATE;
        }
-       return (TRUE);
+       if (opt & AR_OPT_VERBOSE) {
+               archive_handle->action_header = header_verbose_list_ar;
+       }
+#if ENABLE_FEATURE_AR_CREATE
+       archive_handle->ar__name = *argv;
+#endif
+       archive_handle->src_fd = xopen(*argv++,
+                       (opt & AR_CMD_INSERT)
+                               ? O_RDWR | O_CREAT
+                               : O_RDONLY
+       );
+
+       if (*argv)
+               archive_handle->filter = filter_accept_list;
+       while (*argv) {
+               llist_add_to_end(&archive_handle->accept, *argv++);
+       }
+
+#if ENABLE_FEATURE_AR_CREATE
+       if (opt & AR_CMD_INSERT)
+               return write_ar_archive(archive_handle);
+#endif
+
+       unpack_ar_archive(archive_handle);
+
+       return EXIT_SUCCESS;
 }