3260 linker is insufficiently careful with strtok

[illumos-gate.git] / usr / src / cmd / sgs / rtld / common / cap.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include        <sys/types.h>
#include        <sys/mman.h>
#include        <dirent.h>
#include        <stdio.h>
#include        <stdlib.h>
#include        <string.h>
#include        <limits.h>
#include        <debug.h>
#include        <conv.h>
#include        <elfcap.h>
#include        "_rtld.h"
#include        "_elf.h"
#include        "_audit.h"
#include        "msg.h"

/*
 * qsort(3c) capability comparison function.
 */
static int
compare(const void *vp_a, const void *vp_b)
{
        Fdesc   *fdp_a = (Fdesc *)vp_a, *fdp_b = (Fdesc *)vp_b;
        char    *strcap_a, *strcap_b;
        Xword   hwcap_a, hwcap_b;

        /*
         * First, investigate any platform capability.
         */
        strcap_a = fdp_a->fd_scapset.sc_plat;
        strcap_b = fdp_b->fd_scapset.sc_plat;

        if (strcap_a && (strcap_b == NULL))
                return (-1);
        if (strcap_b && (strcap_a == NULL))
                return (1);

        /*
         * Second, investigate any machine capability.
         */
        strcap_a = fdp_a->fd_scapset.sc_mach;
        strcap_b = fdp_b->fd_scapset.sc_mach;

        if (strcap_a && (strcap_b == NULL))
                return (-1);
        if (strcap_b && (strcap_a == NULL))
                return (1);

        /*
         * Third, investigate any CA_SUNW_HW_2 hardware capabilities.
         */
        hwcap_a = fdp_a->fd_scapset.sc_hw_2;
        hwcap_b = fdp_b->fd_scapset.sc_hw_2;

        if (hwcap_a > hwcap_b)
                return (-1);
        if (hwcap_a < hwcap_b)
                return (1);

        /*
         * Finally, investigate any CA_SUNW_HW_1 hardware capabilities.
         */
        hwcap_a = fdp_a->fd_scapset.sc_hw_1;
        hwcap_b = fdp_b->fd_scapset.sc_hw_1;

        if (hwcap_a > hwcap_b)
                return (-1);
        if (hwcap_a < hwcap_b)
                return (1);

        /*
         * Normally, a capabilities directory contains one or more capabilities
         * files, each with different capabilities.  The role of ld.so.1 is to
         * select the best candidate from these variants.  However, we've come
         * across cases where files containing the same capabilities have been
         * placed in the same capabilities directory.  As we can't tell which
         * file is the best, we select neither, and diagnose this suspicious
         * scenario.
         */
        DBG_CALL(Dbg_cap_identical(fdp_a->fd_lml, fdp_a->fd_nname,
            fdp_b->fd_nname));

        fdp_a->fd_flags |= FLG_FD_IGNORE;
        fdp_b->fd_flags |= FLG_FD_IGNORE;

        return (0);
}

/*
 * Determine whether HWCAP1 capabilities value is supported.
 */
int
hwcap1_check(Syscapset *scapset, Xword val, Rej_desc *rej)
{
        Xword   mval;

        /*
         * Ensure that the kernel can cope with the required capabilities.
         */
        if ((rtld_flags2 & RT_FL2_HWCAP) &&
            ((mval = (val & ~scapset->sc_hw_1)) != 0)) {
                if (rej) {
                        static Conv_cap_val_hw1_buf_t   cap_buf;

                        rej->rej_type = SGS_REJ_HWCAP_1;
                        rej->rej_str = conv_cap_val_hw1(mval,
                            M_MACH, 0, &cap_buf);
                }
                return (0);
        }
        return (1);
}

/*
 * Determine whether HWCAP2 capabilities value is supported.
 */
int
hwcap2_check(Syscapset *scapset, Xword val, Rej_desc *rej)
{
        Xword   mval;

        /*
         * Ensure that the kernel can cope with the required capabilities.
         */
        if ((mval = (val & ~scapset->sc_hw_2)) != 0) {
                if (rej) {
                        static Conv_cap_val_hw2_buf_t   cap_buf;

                        rej->rej_type = SGS_REJ_HWCAP_2;
                        rej->rej_str = conv_cap_val_hw2(mval,
                            M_MACH, 0, &cap_buf);
                }
                return (0);
        }
        return (1);
}

/*
 * Process any software capabilities.
 */
/* ARGSUSED0 */
int
sfcap1_check(Syscapset *scapset, Xword val, Rej_desc *rej)
{
#if     defined(_ELF64)
        /*
         * A 64-bit executable that started the process can be restricted to a
         * 32-bit address space.  A 64-bit dependency that is restricted to a
         * 32-bit address space can not be loaded unless the executable has
         * established this requirement.
         */
        if ((val & SF1_SUNW_ADDR32) && ((rtld_flags2 & RT_FL2_ADDR32) == 0)) {
                if (rej) {
                        static Conv_cap_val_sf1_buf_t   cap_buf;

                        rej->rej_type = SGS_REJ_SFCAP_1;
                        rej->rej_str = conv_cap_val_sf1(SF1_SUNW_ADDR32,
                            M_MACH, 0, &cap_buf);
                }
                return (0);
        }
#endif
        return (1);
}

/*
 * Process any platform capability.
 */
int
platcap_check(Syscapset *scapset, const char *str, Rej_desc *rej)
{
        /*
         * If the platform name hasn't been set, try and obtain it.
         */
        if ((scapset->sc_plat == NULL) &&
            (scapset->sc_platsz == 0))
                platform_name(scapset);

        if ((scapset->sc_plat == NULL) ||
            (str && strcmp(scapset->sc_plat, str))) {
                if (rej) {
                        /*
                         * Note, the platform name points to a string within an
                         * objects string table, and if that object can't be
                         * loaded, it will be unloaded and thus invalidate the
                         * string.  Duplicate the string here for rejection
                         * message inheritance.
                         */
                        rej->rej_type = SGS_REJ_PLATCAP;
                        rej->rej_str = stravl_insert(str, 0, 0, 0);
                }
                return (0);
        }
        return (1);
}

/*
 * Process any machine capability.
 */
int
machcap_check(Syscapset *scapset, const char *str, Rej_desc *rej)
{
        /*
         * If the machine name hasn't been set, try and obtain it.
         */
        if ((scapset->sc_mach == NULL) &&
            (scapset->sc_machsz == 0))
                machine_name(scapset);

        if ((scapset->sc_mach == NULL) ||
            (str && strcmp(scapset->sc_mach, str))) {
                if (rej) {
                        /*
                         * Note, the machine name points to a string within an
                         * objects string table, and if that object can't be
                         * loaded, it will be unloaded and thus invalidate the
                         * string.  Duplicate the string here for rejection
                         * message inheritance.
                         */
                        rej->rej_type = SGS_REJ_MACHCAP;
                        rej->rej_str = stravl_insert(str, 0, 0, 0);
                }
                return (0);
        }
        return (1);
}

/*
 * Generic front-end to capabilities validation.
 */
static int
cap_check(Cap *cptr, char *strs, int alt, Fdesc *fdp, Rej_desc *rej)
{
        Syscapset       *scapset;
        int             totplat, ivlplat, totmach, ivlmach;

        /*
         * If the caller has no capabilities, then the object is valid.
         */
        if (cptr == NULL)
                return (1);

        if (alt)
                scapset = alt_scapset;
        else
                scapset = org_scapset;

        totplat = ivlplat = totmach = ivlmach = 0;

        while (cptr->c_tag != CA_SUNW_NULL) {
                Xword   val = cptr->c_un.c_val;
                char    *str;

                switch (cptr->c_tag) {
                case CA_SUNW_HW_1:
                        /*
                         * Remove any historic values that should not be
                         * involved with any validation.
                         */
                        val &= ~AV_HW1_IGNORE;

                        if (hwcap1_check(scapset, val, rej) == 0)
                                return (0);
                        if (fdp)
                                fdp->fd_scapset.sc_hw_1 = val;
                        break;
                case CA_SUNW_SF_1:
                        if (sfcap1_check(scapset, val, rej) == 0)
                                return (0);
                        if (fdp)
                                fdp->fd_scapset.sc_sf_1 = val;
                        break;
                case CA_SUNW_HW_2:
                        if (hwcap2_check(scapset, val, rej) == 0)
                                return (0);
                        if (fdp)
                                fdp->fd_scapset.sc_hw_2 = val;
                        break;
                case CA_SUNW_PLAT:
                        /*
                         * A capabilities group can define multiple platform
                         * names that are appropriate.  Only if all the names
                         * are deemed invalid is the group determined
                         * inappropriate.
                         */
                        if (totplat == ivlplat) {
                                totplat++;

                                str = strs + val;

                                if (platcap_check(scapset, str, rej) == 0)
                                        ivlplat++;
                                else if (fdp)
                                        fdp->fd_scapset.sc_plat = str;
                        }
                        break;
                case CA_SUNW_MACH:
                        /*
                         * A capabilities group can define multiple machine
                         * names that are appropriate.  Only if all the names
                         * are deemed invalid is the group determined
                         * inappropriate.
                         */
                        if (totmach == ivlmach) {
                                totmach++;

                                str = strs + val;

                                if (machcap_check(scapset, str, rej) == 0)
                                        ivlmach++;
                                else if (fdp)
                                        fdp->fd_scapset.sc_mach = str;
                        }
                        break;
                case CA_SUNW_ID:
                        /*
                         * Capabilities identifiers provide for diagnostics,
                         * but are not attributes that must be compared with
                         * the system.  They are ignored.
                         */
                        break;
                default:
                        rej->rej_type = SGS_REJ_UNKCAP;
                        rej->rej_info = cptr->c_tag;
                        return (0);
                }
                cptr++;
        }

        /*
         * If any platform names, or machine names were found, and all were
         * invalid, indicate that the object is inappropriate.
         */
        if ((totplat && (totplat == ivlplat)) ||
            (totmach && (totmach == ivlmach)))
                return (0);

        return (1);
}

#define HWAVL_RECORDED(n)       pnavl_recorded(&capavl, n, NULL, NULL)

/*
 * Determine whether a link-map should use alternative system capabilities.
 */
static void
cap_check_lmp_init(Rt_map *lmp)
{
        int     alt = 0;

        /*
         * If an alternative set of system capabilities have been established,
         * and only specific files should use these alternative system
         * capabilities, determine whether this file is one of those specified.
         */
        if (capavl) {
                const char      *file;

                /*
                 * The simplest way to reference a file is to use its file name
                 * (soname), however try all of the names that this file is
                 * known by.
                 */
                if ((file = strrchr(NAME(lmp), '/')) != NULL)
                        file++;
                else
                        file = NULL;

                if ((file && (HWAVL_RECORDED(file) != 0)) ||
                    (HWAVL_RECORDED(NAME(lmp)) != 0) ||
                    ((PATHNAME(lmp) != NAME(lmp)) &&
                    (HWAVL_RECORDED(PATHNAME(lmp)) != 0)))
                        alt = 1;

                if (alt == 0) {
                        Aliste          idx;
                        const char      *cp;

                        for (APLIST_TRAVERSE(ALIAS(lmp), idx, cp)) {
                                if ((alt = HWAVL_RECORDED(cp)) != 0)
                                        break;
                        }
                }
        }

        /*
         * Indicate if this link-map should use alternative system capabilities,
         * and that the alternative system capabilities check has been carried
         * out.
         */
        if ((org_scapset != alt_scapset) && ((capavl == NULL) || alt))
                FLAGS1(lmp) |= FL1_RT_ALTCAP;
        FLAGS1(lmp) |= FL1_RT_ALTCHECK;
}

/*
 * Validate the capabilities requirements of a link-map.
 *
 * This routine is called for main, where a link-map is constructed from the
 * mappings returned from exec(), and for any symbol capabilities comparisons.
 */
int
cap_check_lmp(Rt_map *lmp, Rej_desc *rej)
{
        if ((FLAGS1(lmp) & FL1_RT_ALTCHECK) == 0)
                cap_check_lmp_init(lmp);

        return (cap_check(CAP(lmp), STRTAB(lmp),
            (FLAGS1(lmp) & FL1_RT_ALTCAP), NULL, rej));
}

/*
 * Validate the capabilities requirements of a file under inspection.
 * This file is still under the early stages of loading, and has no link-map
 * yet.  The file must have an object capabilities definition (PT_SUNWCAP), to
 * have gotten us here.  The logic here is the same as cap_check_lmp().
 */
int
cap_check_fdesc(Fdesc *fdp, Cap *cptr, char *strs, Rej_desc *rej)
{
        int     alt = 0;

        /*
         * If an alternative set of system capabilities have been established,
         * and only specific files should use these alternative system
         * capabilities, determine whether this file is one of those specified.
         */
        if (capavl) {
                const char      *file;

                /*
                 * The simplest way to reference a file is to use its file name
                 * (soname), however try all of the names that this file is
                 * known by.
                 */
                if (fdp->fd_oname &&
                    ((file = strrchr(fdp->fd_oname, '/')) != NULL))
                        file++;
                else
                        file = NULL;

                if ((file && (HWAVL_RECORDED(file) != 0)) ||
                    (fdp->fd_oname && (HWAVL_RECORDED(fdp->fd_oname) != 0)) ||
                    (fdp->fd_nname && (HWAVL_RECORDED(fdp->fd_nname) != 0)) ||
                    (fdp->fd_pname && (fdp->fd_pname != fdp->fd_nname) &&
                    (HWAVL_RECORDED(fdp->fd_pname) != 0)))
                        alt = 1;
        }

        /*
         * Indicate if this file descriptor should use alternative system
         * capabilities, and that the alternative system capabilities check has
         * been carried out.
         */
        if ((org_scapset != alt_scapset) && ((capavl == NULL) || alt))
                fdp->fd_flags |= FLG_FD_ALTCAP;
        fdp->fd_flags |= FLG_FD_ALTCHECK;

        /*
         * Verify that the required capabilities are supported by the reference.
         */
        return (cap_check(cptr, strs, (fdp->fd_flags & FLG_FD_ALTCAP),
            fdp, rej));
}

/*
 * Free a file descriptor list.  As part of building this list, the original
 * names for each capabilities candidate were duplicated for use in later
 * diagnostics.  These names need to be freed.
 */
void
free_fd(Alist *fdalp)
{
        if (fdalp) {
                Aliste  idx;
                Fdesc   *fdp;

                for (ALIST_TRAVERSE(fdalp, idx, fdp)) {
                        if (fdp->fd_oname)
                                free((void *)fdp->fd_oname);
                }
                free(fdalp);
        }
}

/*
 * When $CAPABILITY (or $HWCAP) is used to represent dependencies, take the
 * associated directory and analyze all the files it contains.
 */
static int
cap_dir(Alist **fdalpp, Lm_list *lml, const char *dname, Rt_map *clmp,
    uint_t flags, Rej_desc *rej, int *in_nfavl)
{
        char            path[PATH_MAX], *dst;
        const char      *src;
        DIR             *dir;
        struct dirent   *dirent;
        Alist           *fdalp = NULL;
        Aliste          idx;
        Fdesc           *fdp;
        int             error = 0;

        /*
         * Access the directory in preparation for reading its entries.  If
         * successful, establish the initial pathname.
         */
        if ((dir = opendir(dname)) == NULL) {
                Rej_desc        _rej = { 0 };

                _rej.rej_type = SGS_REJ_STR;
                _rej.rej_name = dname;
                _rej.rej_str = strerror(errno);
                DBG_CALL(Dbg_file_rejected(lml, &_rej, M_MACH));
                rejection_inherit(rej, &_rej);
                return (0);
        }

        for (dst = path, src = dname; *src; dst++, src++)
                *dst = *src;
        *dst++ = '/';

        /*
         * Read each entry from the directory and determine whether it is a
         * valid ELF file.
         */
        while ((dirent = readdir(dir)) != NULL) {
                const char      *file = dirent->d_name;
                char            *_dst;
                Fdesc           fd = { 0 };
                Rej_desc        _rej = { 0 };
                Pdesc           pd = { 0 };

                /*
                 * Ignore "." and ".." entries.
                 */
                if ((file[0] == '.') && ((file[1] == '\0') ||
                    ((file[1] == '.') && (file[2] == '\0'))))
                        continue;

                /*
                 * Complete the full pathname.
                 */
                for (_dst = dst, src = file, file = dst; *src; _dst++, src++)
                        *_dst = *src;
                *_dst = '\0';

                /*
                 * Trace the inspection of this file, and determine any
                 * auditor substitution.
                 */
                pd.pd_pname = path;
                pd.pd_flags = PD_FLG_PNSLASH;

                if (load_trace(lml, &pd, clmp, &fd) == NULL)
                        continue;

                /*
                 * Note, all directory entries are processed by find_path(),
                 * even entries that are directories themselves.  This single
                 * point for control keeps the number of stat()'s down, and
                 * provides a single point for error diagnostics.
                 */
                if (find_path(lml, clmp, flags, &fd, &_rej, in_nfavl) == 0) {
                        rejection_inherit(rej, &_rej);
                        continue;
                }

                DBG_CALL(Dbg_cap_candidate(lml, fd.fd_nname));

                /*
                 * If this object has already been loaded, save the capabilities
                 * for later sorting.  Otherwise we have a new candidate.
                 */
                if (fd.fd_lmp)
                        fd.fd_scapset = CAPSET(fd.fd_lmp);
                fd.fd_lml = lml;

                /*
                 * Duplicate the original name, as this may be required for
                 * later diagnostics.  Keep a copy of the file descriptor for
                 * analysis once all capabilities candidates have been
                 * determined.
                 */
                if (((fd.fd_oname = strdup(fd.fd_oname)) == NULL) ||
                    (alist_append(&fdalp, &fd, sizeof (Fdesc),
                    AL_CNT_CAP) == NULL)) {
                        error = 1;
                        break;
                }
        }
        (void) closedir(dir);

        /*
         * If no objects have been found, we're done.  Also, if an allocation
         * error occurred while processing any object, remove any objects that
         * had already been added to the list and return.
         */
        if ((fdalp == NULL) || error) {
                if (fdalp)
                        free_fd(fdalp);
                return (0);
        }

        /*
         * Having processed and retained all candidates from this directory,
         * sort them, based on the precedence of their hardware capabilities.
         */
        qsort(fdalp->al_data, fdalp->al_nitems, fdalp->al_size, compare);

        /*
         * If any objects were found to have the same capabilities, then these
         * objects must be rejected, as we can't tell which object is more
         * appropriate.
         */
        for (ALIST_TRAVERSE(fdalp, idx, fdp)) {
                if (fdp->fd_flags & FLG_FD_IGNORE)
                        alist_delete(fdalp, &idx);
        }

        if (fdalp->al_nitems == 0) {
                free_fd(fdalp);
                return (0);
        }

        *fdalpp = fdalp;
        return (1);
}

int
cap_filtees(Alist **alpp, Aliste oidx, const char *dir, Aliste nlmco,
    Rt_map *flmp, Rt_map *clmp, const char *ref, int mode, uint_t flags,
    int *in_nfavl)
{
        Alist           *fdalp = NULL;
        Aliste          idx;
        Fdesc           *fdp;
        Lm_list         *lml = LIST(flmp);
        int             unused = 0;
        Rej_desc        rej = { 0 };

        if (cap_dir(&fdalp, lml, dir, flmp, flags, &rej, in_nfavl) == 0)
                return (0);

        /*
         * Now complete the mapping of each of the ordered objects, adding
         * each object to a new pathname descriptor.
         */
        for (ALIST_TRAVERSE(fdalp, idx, fdp)) {
                Rt_map  *nlmp;
                Grp_hdl *ghp = NULL;
                Pdesc   *pdp;
                int     audit = 0;

                if (unused)
                        continue;

                /*
                 * Complete mapping the file, obtaining a handle, and continue
                 * to analyze the object, establishing dependencies and
                 * relocating.  Remove the file descriptor at this point, as it
                 * is no longer required.
                 */
                DBG_CALL(Dbg_file_filtee(lml, NAME(flmp), fdp->fd_nname, 0));

                nlmp = load_path(lml, nlmco, flmp, mode,
                    (flags | FLG_RT_PUBHDL), &ghp, fdp, &rej, in_nfavl);
                if (nlmp == NULL)
                        continue;

                /*
                 * Create a new pathname descriptor to represent this filtee,
                 * and insert this descriptor in the Alist following the
                 * hardware descriptor that seeded this processing.
                 */
                if ((pdp = alist_insert(alpp, 0, sizeof (Pdesc),
                    AL_CNT_FILTEES, ++oidx)) == NULL) {
                        if (ghp)
                                remove_lmc(lml, flmp, nlmco, NAME(nlmp));
                        return (0);
                }

                pdp->pd_pname = NAME(nlmp);
                pdp->pd_plen = strlen(NAME(nlmp));

                /*
                 * Establish the filter handle to prevent any recursion.
                 */
                if (nlmp && ghp) {
                        ghp->gh_flags |= GPH_FILTEE;
                        pdp->pd_info = (void *)ghp;
                }

                /*
                 * Audit the filter/filtee established.  A return of 0
                 * indicates the auditor wishes to ignore this filtee.
                 */
                if (nlmp && (lml->lm_tflags | FLAGS1(flmp)) &
                    LML_TFLG_AUD_OBJFILTER) {
                        if (audit_objfilter(flmp, ref, nlmp, 0) == 0) {
                                audit = 1;
                                nlmp = NULL;
                        }
                }

                /*
                 * Finish processing the objects associated with this request.
                 */
                if (nlmp && ghp && (((nlmp = analyze_lmc(lml, nlmco, nlmp,
                    clmp, in_nfavl)) == NULL) ||
                    (relocate_lmc(lml, nlmco, flmp, nlmp, in_nfavl) == 0)))
                        nlmp = NULL;

                /*
                 * If the filtee has been successfully processed, then create
                 * an association between the filter and the filtee.  This
                 * association provides sufficient information to tear down the
                 * filter and filtee if necessary.
                 */
                DBG_CALL(Dbg_file_hdl_title(DBG_HDL_ADD));
                if (nlmp && ghp &&
                    (hdl_add(ghp, flmp, GPD_FILTER, NULL) == NULL))
                        nlmp = NULL;

                /*
                 * If this object is marked an end-filtee, we're done.
                 */
                if (nlmp && ghp && (FLAGS1(nlmp) & FL1_RT_ENDFILTE))
                        unused = 1;

                /*
                 * If this filtee loading has failed, generate a diagnostic.
                 * Null out the path name descriptor entry, and continue the
                 * search.
                 */
                if (nlmp == NULL) {
                        DBG_CALL(Dbg_file_filtee(lml, 0, pdp->pd_pname, audit));

                        /*
                         * If attempting to load this filtee required a new
                         * link-map control list to which this request has
                         * added objects, then remove all the objects that
                         * have been associated to this request.
                         */
                        if (nlmco != ALIST_OFF_DATA)
                                remove_lmc(lml, flmp, nlmco, pdp->pd_pname);

                        pdp->pd_plen = 0;
                        pdp->pd_info = NULL;
                }
        }

        free_fd(fdalp);
        return (1);
}

/*
 * Load an individual capabilities object.
 */
Rt_map *
load_cap(Lm_list *lml, Aliste lmco, const char *dir, Rt_map *clmp,
    uint_t mode, uint_t flags, Grp_hdl **hdl, Rej_desc *rej, int *in_nfavl)
{
        Alist   *fdalp = NULL;
        Aliste  idx;
        Fdesc   *fdp;
        int     found = 0;
        Rt_map  *lmp = NULL;

        /*
         * Obtain the sorted list of hardware capabilities objects available.
         */
        if (cap_dir(&fdalp, lml, dir, clmp, flags, rej, in_nfavl) == 0)
                return (NULL);

        /*
         * From the list of hardware capability objects, use the first and
         * discard the rest.
         */
        for (ALIST_TRAVERSE(fdalp, idx, fdp)) {
                Fdesc   fd = *fdp;

                if ((found == 0) && ((lmp = load_path(lml, lmco, clmp, mode,
                    flags, hdl, &fd, rej, in_nfavl)) != NULL))
                        found++;
        }

        free_fd(fdalp);
        return (lmp);
}

/*
 * Use a case insensitive string match when looking up capability mask
 * values by name, and omit the AV_ prefix.
 */
#define ELFCAP_STYLE    ELFCAP_STYLE_LC | ELFCAP_STYLE_F_ICMP

/*
 * To aid in the development and testing of capabilities, an alternative system
 * capabilities group can be specified.  This alternative set is initialized
 * from the system capabilities that are normally used to validate all object
 * loading.  However, the user can disable, enable or override flags within
 * this alternative set, and thus affect object loading.
 *
 * This technique is usually combined with defining the family of objects
 * that should be compared against this alternative set.  Without defining the
 * family of objects, all objects loaded by ld.so.1 are validated against the
 * alternative set.  This can prevent the loading of critical system objects
 * like libc, and thus prevent process execution.
 */
typedef enum {
        CAP_OVERRIDE =  0,              /* override existing capabilities */
        CAP_ENABLE =    1,              /* enable capabilities */
        CAP_DISABLE =   2               /* disable capabilities */
} cap_mode;

static struct {
        elfcap_mask_t   cs_val[3];      /* value settings, and indicator for */
        int             cs_set[3];      /*      OVERRIDE, ENABLE and DISABLE */
        elfcap_mask_t   *cs_aval;       /* alternative variable for final */
                                        /*      update */
} cap_settings[3] = {
        { { 0, 0, 0 }, { 0, 0, 0 }, NULL },             /* CA_SUNW_HW_1 */
        { { 0, 0, 0 }, { 0, 0, 0 }, NULL },             /* CA_SUNW_SF_1 */
        { { 0, 0, 0 }, { 0, 0, 0 }, NULL }              /* CA_SUNW_HW_2 */
};

static int
cap_modify(Xword tag, const char *str)
{
        char            *caps, *ptr, *next;
        cap_mode        mode = CAP_OVERRIDE;
        Xword           ndx;

        if ((caps = strdup(str)) == NULL)
                return (0);

        for (ptr = strtok_r(caps, MSG_ORIG(MSG_CAP_DELIMIT), &next);
            ptr != NULL;
            ptr = strtok_r(NULL, MSG_ORIG(MSG_CAP_DELIMIT), &next)) {
                Xword           val = 0;

                /*
                 * Determine whether this token should be enabled (+),
                 * disabled (-), or override any existing settings.
                 */
                if (*ptr == '+') {
                        mode = CAP_ENABLE;
                        ptr++;
                } else if (*ptr == '-') {
                        mode = CAP_DISABLE;
                        ptr++;
                }

                /*
                 * Process the capabilities as directed by the calling tag.
                 */
                switch (tag) {
                case CA_SUNW_HW_1:
                        /*
                         * Determine whether the capabilities string matches
                         * a known hardware capability mask.  Note, the caller
                         * indicates that these are hardware capabilities by
                         * passing in the CA_SUNW_HW_1 tag.  However, the
                         * tokens could be CA_SUNW_HW_1 or CA_SUNW_HW_2.
                         */
                        if ((val = (Xword)elfcap_hw2_from_str(ELFCAP_STYLE,
                            ptr, M_MACH)) != 0) {
                                ndx = CA_SUNW_HW_2;
                                break;
                        }
                        if ((val = (Xword)elfcap_hw1_from_str(ELFCAP_STYLE,
                            ptr, M_MACH)) != 0)
                                ndx = CA_SUNW_HW_1;
                        break;
                case CA_SUNW_SF_1:
                        /*
                         * Determine whether the capabilities string matches a
                         * known software capability mask.  Note, the callers
                         * indication of what capabilities to process are
                         * triggered by a tag of CA_SUNW_SF_1, but the tokens
                         * processed could be CA_SUNW_SF_1, CA_SUNW_SF_2, etc.
                         */
                        if ((val = (Xword)elfcap_sf1_from_str(ELFCAP_STYLE,
                            ptr, M_MACH)) != 0)
                                ndx = CA_SUNW_SF_1;
                        break;
                }

                /*
                 * If a capabilities token has not been matched, interpret the
                 * string as a number.  To provide for setting the various
                 * families (CA_SUNW_HW_1, CA_SUNW_HW_2), the number can be
                 * prefixed with the (bracketed) family index.
                 *
                 *      LD_HWCAP=[1]0x40    sets CA_SUNW_HW_1 with 0x40
                 *      LD_HWCAP=[2]0x80    sets CA_SUNW_HW_2 with 0x80
                 *
                 * Invalid indexes are ignored.
                 */
                if (val == 0) {
                        if ((*ptr == '[') && (*(ptr + 2) == ']')) {
                                if (*(ptr + 1) == '1') {
                                        ndx = tag;
                                        ptr += 3;
                                } else if (*(ptr + 1) == '2') {
                                        if (tag == CA_SUNW_HW_1) {
                                                ndx = CA_SUNW_HW_2;
                                                ptr += 3;
                                        } else {
                                                /* invalid index */
                                                continue;
                                        }
                                } else {
                                        /* invalid index */
                                        continue;
                                }
                        } else
                                ndx = tag;

                        errno = 0;
                        if (((val = strtol(ptr, NULL, 16)) == 0) && errno)
                                continue;
                }
                cap_settings[ndx - 1].cs_val[mode] |= val;
                cap_settings[ndx - 1].cs_set[mode]++;

        }

        /*
         * If the "override" token was supplied, set the alternative
         * system capabilities, then enable or disable others.
         */
        for (ndx = 0; ndx < CA_SUNW_HW_2; ndx++) {
                if (cap_settings[ndx].cs_set[CAP_OVERRIDE])
                        *(cap_settings[ndx].cs_aval) =
                            cap_settings[ndx].cs_val[CAP_OVERRIDE];
                if (cap_settings[ndx].cs_set[CAP_ENABLE])
                        *(cap_settings[ndx].cs_aval) |=
                            cap_settings[ndx].cs_val[CAP_ENABLE];
                if (cap_settings[ndx].cs_set[CAP_DISABLE])
                        *(cap_settings[ndx].cs_aval) &=
                            ~cap_settings[ndx].cs_val[CAP_DISABLE];
        }
        free(caps);
        return (1);
}
#undef  ELFCAP_STYLE

/*
 * Create an AVL tree of objects that are to be validated against an alternative
 * system capabilities value.
 */
static int
cap_files(const char *str)
{
        char    *caps, *name, *next;

        if ((caps = strdup(str)) == NULL)
                return (0);

        for (name = strtok_r(caps, MSG_ORIG(MSG_CAP_DELIMIT), &next);
            name != NULL;
            name = strtok_r(NULL, MSG_ORIG(MSG_CAP_DELIMIT), &next)) {
                avl_index_t     where;
                PathNode        *pnp;
                uint_t          hash = sgs_str_hash(name);

                /*
                 * Determine whether this pathname has already been recorded.
                 */
                if (pnavl_recorded(&capavl, name, hash, &where))
                        continue;

                if ((pnp = calloc(sizeof (PathNode), 1)) != NULL) {
                        pnp->pn_name = name;
                        pnp->pn_hash = hash;
                        avl_insert(capavl, pnp, where);
                }
        }

        return (1);
}

/*
 * Set alternative system capabilities.  A user can establish alternative system
 * capabilities from the environment, or from a configuration file.  This
 * routine is called in each instance.  Environment variables only set the
 * replaceable (rpl) variables.  Configuration files can set both replaceable
 * (rpl) and permanent (prm) variables.
 */
int
cap_alternative(void)
{
        /*
         * If no capabilities have been set, we're done.
         */
        if ((rpl_hwcap == NULL) && (rpl_sfcap == NULL) &&
            (rpl_machcap == NULL) && (rpl_platcap == NULL) &&
            (prm_hwcap == NULL) && (prm_sfcap == NULL) &&
            (prm_machcap == NULL) && (prm_platcap == NULL))
                return (1);

        /*
         * If the user has requested to modify any capabilities, establish a
         * unique set from the present system capabilities.
         */
        if ((alt_scapset = malloc(sizeof (Syscapset))) == NULL)
                return (0);
        *alt_scapset = *org_scapset;

        cap_settings[CA_SUNW_HW_1 - 1].cs_aval = &alt_scapset->sc_hw_1;
        cap_settings[CA_SUNW_SF_1 - 1].cs_aval = &alt_scapset->sc_sf_1;
        cap_settings[CA_SUNW_HW_2 - 1].cs_aval = &alt_scapset->sc_hw_2;

        /*
         * Process any replaceable variables.
         */
        if (rpl_hwcap && (cap_modify(CA_SUNW_HW_1, rpl_hwcap) == 0))
                return (0);
        if (rpl_sfcap && (cap_modify(CA_SUNW_SF_1, rpl_sfcap) == 0))
                return (0);

        if (rpl_platcap) {
                alt_scapset->sc_plat = (char *)rpl_platcap;
                alt_scapset->sc_platsz = strlen(rpl_platcap);
        }
        if (rpl_machcap) {
                alt_scapset->sc_mach = (char *)rpl_machcap;
                alt_scapset->sc_machsz = strlen(rpl_machcap);
        }

        if (rpl_cap_files && (cap_files(rpl_cap_files) == 0))
                return (0);

        /*
         * Process any permanent variables.
         */
        if (prm_hwcap && (cap_modify(CA_SUNW_HW_1, prm_hwcap) == 0))
                return (0);
        if (prm_sfcap && (cap_modify(CA_SUNW_SF_1, prm_sfcap) == 0))
                return (0);

        if (prm_platcap) {
                alt_scapset->sc_plat = (char *)prm_platcap;
                alt_scapset->sc_platsz = strlen(prm_platcap);
        }
        if (prm_machcap) {
                alt_scapset->sc_mach = (char *)prm_machcap;
                alt_scapset->sc_machsz = strlen(prm_machcap);
        }

        if (prm_cap_files && (cap_files(prm_cap_files) == 0))
                return (0);

        /*
         * Reset the replaceable variables.  If this is the environment variable
         * processing, these variables are now available for configuration file
         * initialization.
         */
        rpl_hwcap = rpl_sfcap = rpl_machcap = rpl_platcap =
            rpl_cap_files = NULL;

        return (1);
}

/*
 * Take the index from a Capinfo entry and determine the associated capabilities
 * set.  Verify that the capabilities are available for this system.
 */
static int
sym_cap_check(Cap *cptr, uint_t cndx, Syscapset *bestcapset, Rt_map *lmp,
    const char *name, uint_t ndx)
{
        Syscapset       *scapset;
        int             totplat, ivlplat, totmach, ivlmach, capfail = 0;

        /*
         * Determine whether this file requires validation against alternative
         * system capabilities.
         */
        if ((FLAGS1(lmp) & FL1_RT_ALTCHECK) == 0)
                cap_check_lmp_init(lmp);

        if (FLAGS1(lmp) & FL1_RT_ALTCAP)
                scapset = alt_scapset;
        else
                scapset = org_scapset;

        totplat = ivlplat = totmach = ivlmach = 0;

        /*
         * A capabilities index points to a capabilities group that can consist
         * of one or more capabilities, terminated with a CA_SUNW_NULL entry.
         */
        for (cptr += cndx; cptr->c_tag != CA_SUNW_NULL; cptr++) {
                Xword   val = cptr->c_un.c_val;
                char    *str;

                switch (cptr->c_tag) {
                case CA_SUNW_HW_1:
                        /*
                         * Remove any historic values that should not be
                         * involved with any validation.
                         */
                        val &= ~AV_HW1_IGNORE;

                        bestcapset->sc_hw_1 = val;
                        DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_HW_1,
                            name, ndx, M_MACH, bestcapset));

                        if (hwcap1_check(scapset, val, NULL) == 0)
                                capfail++;
                        break;
                case CA_SUNW_SF_1:
                        bestcapset->sc_sf_1 = val;
                        DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_SF_1,
                            name, ndx, M_MACH, bestcapset));

                        if (sfcap1_check(scapset, val, NULL) == 0)
                                capfail++;
                        break;
                case CA_SUNW_HW_2:
                        bestcapset->sc_hw_2 = val;
                        DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_HW_2,
                            name, ndx, M_MACH, bestcapset));

                        if (hwcap2_check(scapset, val, NULL) == 0)
                                capfail++;
                        break;
                case CA_SUNW_PLAT:
                        /*
                         * A capabilities set can define multiple platform names
                         * that are appropriate.  Only if all the names are
                         * deemed invalid is the group determined inappropriate.
                         */
                        if (totplat == ivlplat) {
                                totplat++;

                                str = STRTAB(lmp) + val;
                                bestcapset->sc_plat = str;

                                DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_PLAT,
                                    name, ndx, M_MACH, bestcapset));

                                if (platcap_check(scapset, str, NULL) == 0)
                                        ivlplat++;
                        }
                        break;
                case CA_SUNW_MACH:
                        /*
                         * A capabilities set can define multiple machine names
                         * that are appropriate.  Only if all the names are
                         * deemed invalid is the group determined inappropriate.
                         */
                        if (totmach == ivlmach) {
                                totmach++;

                                str = STRTAB(lmp) + val;
                                bestcapset->sc_mach = str;

                                DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_MACH,
                                    name, ndx, M_MACH, bestcapset));

                                if (machcap_check(scapset, str, NULL) == 0)
                                        ivlmach++;
                        }
                        break;
                default:
                        break;
                }
        }

        /*
         * If any platform definitions, or machine definitions were found, and
         * all were invalid, indicate that the object is inappropriate.
         */
        if (capfail || (totplat && (totplat == ivlplat)) ||
            (totmach && (totmach == ivlmach))) {
                DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_REJECTED, name, ndx,
                    M_MACH, NULL));
                return (0);
        }

        DBG_CALL(Dbg_syms_cap_lookup(lmp, DBG_CAP_CANDIDATE, name, ndx,
            M_MACH, NULL));
        return (1);
}

/*
 * Determine whether a symbols capabilities are more significant than any that
 * have already been validated.  The precedence of capabilities are:
 *
 *   PLATCAP -> MACHCAP -> HWCAP_2 -> HWCAP_1
 *
 *
 * Presently we make no comparisons of software capabilities.  However, should
 * this symbol capability have required the SF1_SUNW_ADDR32 attribute, then
 * this would have been validated as appropriate or not.
 *
 * bestcapset is the presently available 'best' capabilities group, and
 * symcapset is the present capabilities group under investigation.  Return 0
 * if the bestcapset should remain in affect, or 1 if the symcapset is better.
 */
inline static int
is_sym_the_best(Syscapset *bestcapset, Syscapset *symcapset)
{
        /*
         * Check any platform capability.  If the new symbol isn't associated
         * with a CA_SUNW_PLAT capability, and the best symbol is, then retain
         * the best capabilities group.  If the new symbol is associated with a
         * CA_SUNW_PLAT capability, and the best symbol isn't, then the new
         * symbol needs to be taken.
         */
        if (bestcapset->sc_plat && (symcapset->sc_plat == NULL))
                return (0);

        if ((bestcapset->sc_plat == NULL) && symcapset->sc_plat)
                return (1);

        /*
         * Check any machine name capability.  If the new symbol isn't
         * associated with a CA_SUNW_MACH capability, and the best symbol is,
         * then retain the best capabilities group.  If the new symbol is
         * associated with a CA_SUNW_MACH capability, and the best symbol isn't,
         * then the new symbol needs to be taken.
         */
        if (bestcapset->sc_mach && (symcapset->sc_mach == NULL))
                return (0);

        if ((bestcapset->sc_mach == NULL) && symcapset->sc_mach)
                return (1);

        /*
         * Check the hardware capabilities.  If the best symbols CA_SUNW_HW_2
         * capabilities are greater than the new symbols capabilities, then
         * retain the best capabilities group.  If the new symbols CA_SUNW_HW_2
         * capabilities are greater than the best symbol, then the new symbol
         * needs to be taken.
         */
        if (bestcapset->sc_hw_2 > symcapset->sc_hw_2)
                return (0);

        if (bestcapset->sc_hw_2 < symcapset->sc_hw_2)
                return (1);

        /*
         * Check the remaining hardware capabilities.  If the best symbols
         * CA_SUNW_HW_1 capabilities are greater than the new symbols
         * capabilities, then retain the best capabilities group.  If the new
         * symbols CA_SUNW_HW_1 capabilities are greater than the best symbol,
         * then the new symbol needs to be taken.
         */
        if (bestcapset->sc_hw_1 > symcapset->sc_hw_1)
                return (0);

        if (bestcapset->sc_hw_1 < symcapset->sc_hw_1)
                return (1);

        /*
         * Both capabilities are the same.  Retain the best on a first-come
         * first-served basis.
         */
        return (0);
}

/*
 * Initiate symbol capabilities processing.  If an initial symbol lookup
 * results in binding to a symbol that has an associated SUNW_capinfo entry,
 * we arrive here.
 *
 * The standard model is that this initial symbol is the lead capabilities
 * symbol (defined as CAPINFO_SUNW_GLOB) of a capabilities family.  This lead
 * symbol's SUNW_capinfo information points to the SUNW_capchain entry that
 * provides the family symbol indexes.  We traverse this chain, looking at
 * each family member, to discover the best capabilities instance.  This
 * instance name and symbol information is returned to establish the final
 * symbol binding.
 *
 * If the symbol that got us here is not CAPINFO_SUNW_GLOB, then we've bound
 * directly to a capabilities symbol which must be verified.  This is not the
 * model created by ld(1) using -z symbolcap, but might be created directly
 * within a relocatable object by the compilation system.
 */
int
cap_match(Sresult *srp, uint_t symndx, Sym *symtabptr, char *strtabptr)
{
        Rt_map          *ilmp = srp->sr_dmap;
        Sym             *bsym = NULL;
        const char      *bname;
        Syscapset       bestcapset = { 0 };
        Cap             *cap;
        Capchain        *capchain;
        uchar_t         grpndx;
        uint_t          ochainndx, nchainndx, bndx;

        cap = CAP(ilmp);
        capchain = CAPCHAIN(ilmp);

        grpndx = (uchar_t)ELF_C_GROUP(CAPINFO(ilmp)[symndx]);

        /*
         * If this symbols capability group is not a lead symbol, then simply
         * verify the symbol.
         */
        if (grpndx != CAPINFO_SUNW_GLOB) {
                Syscapset       symcapset = { 0 };

                return (sym_cap_check(cap, grpndx, &symcapset, ilmp,
                    srp->sr_name, symndx));
        }

        /*
         * If there is no capabilities chain, return the lead symbol.
         */
        if (capchain == NULL)
                return (1);

        ochainndx = (uint_t)ELF_C_SYM(CAPINFO(ilmp)[symndx]);

        /*
         * If there is only one member for this family, take it.  Once a family
         * has been processed, the best family instance is written to the head
         * of the chain followed by a null entry.  This caching ensures that the
         * same family comparison doesn't have to be undertaken more than once.
         */
        if (capchain[ochainndx] && (capchain[ochainndx + 1] == 0)) {
                Sym             *fsym = symtabptr + capchain[ochainndx];
                const char      *fname = strtabptr + fsym->st_name;

                DBG_CALL(Dbg_syms_cap_lookup(ilmp, DBG_CAP_USED, fname,
                    capchain[ochainndx], M_MACH, NULL));

                srp->sr_sym = fsym;
                srp->sr_name = fname;
                return (1);
        }

        /*
         * As this symbol is the lead symbol of a capabilities family, it is
         * considered the generic member, and therefore forms the basic
         * fall-back for the capabilities family.
         */
        DBG_CALL(Dbg_syms_cap_lookup(ilmp, DBG_CAP_DEFAULT, srp->sr_name,
            symndx, M_MACH, NULL));
        bsym = srp->sr_sym;
        bname = srp->sr_name;
        bndx = symndx;

        /*
         * Traverse the capabilities chain analyzing each family member.
         */
        for (nchainndx = ochainndx + 1, symndx = capchain[nchainndx]; symndx;
            nchainndx++, symndx = capchain[nchainndx]) {
                Sym             *nsym = symtabptr + symndx;
                const char      *nname = strtabptr + nsym->st_name;
                Syscapset       symcapset = { 0 };

                if ((grpndx =
                    (uchar_t)ELF_C_GROUP(CAPINFO(ilmp)[symndx])) == 0)
                        continue;

                if (sym_cap_check(cap, grpndx, &symcapset, ilmp,
                    nname, symndx) == 0)
                        continue;

                /*
                 * Determine whether a symbol's capabilities are more
                 * significant than any that have already been validated.
                 */
                if (is_sym_the_best(&bestcapset, &symcapset)) {
                        bestcapset = symcapset;
                        bsym = nsym;
                        bname = nname;
                        bndx = symndx;
                }
        }

        DBG_CALL(Dbg_syms_cap_lookup(ilmp, DBG_CAP_USED, bname, bndx,
            M_MACH, NULL));

        /*
         * Having found the best symbol, cache the results by overriding the
         * first element of the associated chain.
         */
        capchain[ochainndx] = bndx;
        capchain[ochainndx + 1] = 0;

        /*
         * Update the symbol result information for return to the user.
         */
        srp->sr_sym = bsym;
        srp->sr_name = bname;
        return (1);
}