usr/src/uts/common/exec/java/java.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  * Copyright 2019 Joyent, Inc.
  25  */
  26
  27 /*
  28  * Launch Java executables via exec(2).
  29  *
  30  * Java executables are platform-independent executable files
  31  * based on the JAR file format.  Executable JAR files contain a
  32  * special 'extra field' header in the first file of the archive
  33  * that marks the file as a true executable.   The data in that field
  34  * is used to pass additional run-time information to the Java VM.
  35  *
  36  * This handler looks for the appropriate magic number on the
  37  * front of the file, checks that the JAR file is executable, then
  38  * invokes the Java runtime environment to do the rest of the work.
  39  */
  40
  41 #include <sys/types.h>
  42 #include <sys/proc.h>
  43 #include <sys/vnode.h>
  44 #include <sys/exec.h>
  45 #include <sys/modctl.h>
  46 #include <sys/cmn_err.h>
  47 #include <sys/pathname.h>
  48
  49 /*
  50  * These variables can be tweaked via /etc/system to allow prototyping
  51  * and debugging.  See PSARC/1997/123.
  52  *
  53  * Modified by PSARC/1999/012 to be Contract Private between Solaris and
  54  * the Java Technology Group.  It is expected that any future change to
  55  * these variables be coordinated between the consolidations.
  56  */
  57 #if defined(__sparc)
  58 char *jexec = "/usr/java/jre/lib/sparc/jexec";
  59 #elif defined(__x86)
  60 char *jexec = "/usr/java/jre/lib/i386/jexec";
  61 #else
  62 #error "Unknown ISA"
  63 #endif
  64 char *jexec_arg = "-jar";
  65
  66 /*
  67  * ZIP/JAR file header information
  68  */
  69 #define SIGSIZ          4
  70 #define LOCSIG          "PK\003\004"
  71 #define LOCHDRSIZ       30
  72
  73 #define CH(b, n)        (((unsigned char *)(b))[n])
  74 #define SH(b, n)        (CH(b, n) | (CH(b, n+1) << 8))
  75 #define LG(b, n)        (SH(b, n) | (SH(b, n+2) << 16))
  76
  77 #define LOCNAM(b)       (SH(b, 26))     /* filename size */
  78 #define LOCEXT(b)       (SH(b, 28))     /* extra field size */
  79
  80 #define XFHSIZ          4               /* header id, data size */
  81 #define XFHID(b)        (SH(b, 0))      /* extract field header id */
  82 #define XFDATASIZ(b)    (SH(b, 2))      /* extract field data size */
  83 #define XFJAVASIG       0xcafe          /* java executables */
  84
  85 /*ARGSUSED3*/
  86 static int
  87 javaexec(vnode_t *vp, struct execa *uap, struct uarg *args,
  88     struct intpdata *idatap, int level, size_t *execsz, int setid,
  89     caddr_t execfile, cred_t *cred, int brand_action)
  90 {
  91         struct intpdata idata;
  92         int error;
  93         ssize_t resid;
  94         vnode_t *nvp;
  95         off_t xoff, xoff_end;
  96         char lochdr[LOCHDRSIZ];
  97         struct pathname lookpn;
  98         struct pathname resolvepn;
  99         char *opath;
 100
 101         if (level)
 102                 return (ENOEXEC);       /* no recursion */
 103
 104         /*
 105          * Read in the full local file header, and validate
 106          * the initial signature.
 107          */
 108         if ((error = vn_rdwr(UIO_READ, vp, lochdr, sizeof (lochdr),
 109             0, UIO_SYSSPACE, 0, (rlim64_t)0, cred, &resid)) != 0)
 110                 return (error);
 111         if (resid != 0 || strncmp(lochdr, LOCSIG, SIGSIZ) != 0)
 112                 return (ENOEXEC);
 113
 114         /*
 115          * Ok, so this -is- a ZIP file, and might even be a JAR file.
 116          * Is it a Java executable?
 117          */
 118         xoff = sizeof (lochdr) + LOCNAM(lochdr);
 119         xoff_end = xoff + LOCEXT(lochdr);
 120
 121         while (xoff < xoff_end) {
 122                 char xfhdr[XFHSIZ];
 123
 124                 if ((error = vn_rdwr(UIO_READ, vp, xfhdr, sizeof (xfhdr),
 125                     xoff, UIO_SYSSPACE, 0, (rlim64_t)0, cred, &resid)) != 0)
 126                         return (error);
 127                 if (resid != 0)
 128                         return (ENOEXEC);
 129                 if (XFHID(xfhdr) == XFJAVASIG)
 130                         break;
 131                 xoff += sizeof (xfhdr) + XFDATASIZ(xfhdr);
 132         }
 133
 134         if (xoff >= xoff_end)
 135                 return (ENOEXEC);
 136
 137         /*
 138          * Note: If we ever make setid execution work, we need to ensure
 139          * that we use /dev/fd to avoid the classic setuid shell script
 140          * security hole.
 141          */
 142         if (setid)
 143                 return (EACCES);
 144
 145         /*
 146          * Find and invoke the Java runtime environment on the file
 147          */
 148         bzero(&idata, sizeof (intpdata_t));
 149         idata.intp = NULL;
 150         idata.intp_name[0] = jexec;
 151         idata.intp_arg[0] = jexec_arg;
 152         if (error = pn_get(idata.intp_name[0], UIO_SYSSPACE, &lookpn))
 153                 return (error);
 154         pn_alloc(&resolvepn);
 155         if (error = lookuppn(&lookpn, &resolvepn, FOLLOW, NULLVPP, &nvp)) {
 156                 pn_free(&resolvepn);
 157                 pn_free(&lookpn);
 158                 return (ENOEXEC);
 159         }
 160         opath = args->pathname;
 161         args->pathname = resolvepn.pn_path;
 162         /* don't free resolvepn until we are done with args */
 163         pn_free(&lookpn);
 164         error = gexec(&nvp, uap, args, &idata, level + 1, execsz, execfile,
 165             cred, EBA_NONE);
 166
 167         if (!error) {
 168                 /*
 169                  * Close this Java executable as the interpreter
 170                  * will open and close it later on.
 171                  */
 172                 (void) VOP_CLOSE(vp, FREAD, 1, (offset_t)0, cred, NULL);
 173         }
 174
 175         VN_RELE(nvp);
 176         args->pathname = opath;
 177         pn_free(&resolvepn);
 178         return (error);
 179 }
 180
 181 static struct execsw jexecsw = {
 182         javamagicstr,
 183         0,
 184         4,
 185         javaexec,
 186         NULL
 187 };
 188
 189 static struct modlexec jmodlexec = {
 190         &mod_execops, "exec for Java", &jexecsw
 191 };
 192
 193 static struct modlinkage jmodlinkage = {
 194         MODREV_1, &jmodlexec, NULL
 195 };
 196
 197 int
 198 _init(void)
 199 {
 200         return (mod_install(&jmodlinkage));
 201 }
 202
 203 int
 204 _fini(void)
 205 {
 206         return (mod_remove(&jmodlinkage));
 207 }
 208
 209 int
 210 _info(struct modinfo *modinfop)
 211 {
 212         return (mod_info(&jmodlinkage, modinfop));
 213 }