Factor out retrieving the interpreter path from the main ELF
loader routine. Reviewed by: kib MFC after: 2 weeks Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D19715
This commit is contained in:
Edward Tomasz Napierala
parent
dd3b96ecec
commit
09c78d53bf
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=345661
@ -88,7 +88,7 @@ __FBSDID("$FreeBSD$");
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static int __elfN(check_header)(const Elf_Ehdr *hdr);
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static Elf_Brandinfo *__elfN(get_brandinfo)(struct image_params *imgp,
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const char *interp, int interp_name_len, int32_t *osrel, uint32_t *fctl0);
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const char *interp, int32_t *osrel, uint32_t *fctl0);
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static int __elfN(load_file)(struct proc *p, const char *file, u_long *addr,
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u_long *entry);
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static int __elfN(load_section)(struct image_params *imgp, vm_ooffset_t offset,
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@ -272,12 +272,14 @@ __elfN(brand_inuse)(Elf_Brandinfo *entry)
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static Elf_Brandinfo *
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__elfN(get_brandinfo)(struct image_params *imgp, const char *interp,
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int interp_name_len, int32_t *osrel, uint32_t *fctl0)
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int32_t *osrel, uint32_t *fctl0)
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{
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const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;
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Elf_Brandinfo *bi, *bi_m;
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boolean_t ret;
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int i;
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int i, interp_name_len;
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interp_name_len = interp != NULL ? strlen(interp) : 0;
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/*
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* We support four types of branding -- (1) the ELF EI_OSABI field
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@ -889,6 +891,60 @@ __elfN(enforce_limits)(struct image_params *imgp, const Elf_Ehdr *hdr,
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return (0);
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}
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static int
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__elfN(get_interp)(struct image_params *imgp, const Elf_Phdr *phdr,
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char **interpp, bool *free_interpp)
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{
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struct thread *td;
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char *interp;
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int error, interp_name_len;
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KASSERT(phdr->p_type == PT_INTERP,
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("%s: p_type %u != PT_INTERP", __func__, phdr->p_type));
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KASSERT(VOP_ISLOCKED(imgp->vp),
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("%s: vp %p is not locked", __func__, imgp->vp));
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td = curthread;
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/* Path to interpreter */
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if (phdr->p_filesz < 2 || phdr->p_filesz > MAXPATHLEN) {
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uprintf("Invalid PT_INTERP\n");
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return (ENOEXEC);
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}
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interp_name_len = phdr->p_filesz;
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if (phdr->p_offset > PAGE_SIZE ||
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interp_name_len > PAGE_SIZE - phdr->p_offset) {
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VOP_UNLOCK(imgp->vp, 0);
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interp = malloc(interp_name_len + 1, M_TEMP, M_WAITOK);
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vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
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error = vn_rdwr(UIO_READ, imgp->vp, interp,
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interp_name_len, phdr->p_offset,
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UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
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NOCRED, NULL, td);
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if (error != 0) {
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free(interp, M_TEMP);
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uprintf("i/o error PT_INTERP %d\n", error);
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return (error);
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}
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interp[interp_name_len] = '\0';
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*interpp = interp;
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*free_interpp = true;
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return (0);
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}
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interp = __DECONST(char *, imgp->image_header) + phdr->p_offset;
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if (interp[interp_name_len - 1] != '\0') {
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uprintf("Invalid PT_INTERP\n");
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return (ENOEXEC);
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}
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*interpp = interp;
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*free_interpp = false;
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return (0);
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}
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/*
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* Impossible et_dyn_addr initial value indicating that the real base
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* must be calculated later with some randomization applied.
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@ -905,7 +961,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
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struct vmspace *vmspace;
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vm_map_t map;
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const char *newinterp;
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char *interp, *interp_buf, *path;
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char *interp, *path;
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Elf_Brandinfo *brand_info;
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struct sysentvec *sv;
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vm_prot_t prot;
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@ -913,7 +969,8 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
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u_long maxalign, mapsz, maxv, maxv1;
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uint32_t fctl0;
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int32_t osrel;
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int error, i, n, interp_name_len, have_interp;
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bool free_interp;
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int error, i, n, have_interp;
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hdr = (const Elf_Ehdr *)imgp->image_header;
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@ -949,9 +1006,8 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
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osrel = 0;
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fctl0 = 0;
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entry = proghdr = 0;
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interp_name_len = 0;
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newinterp = NULL;
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interp = interp_buf = NULL;
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newinterp = interp = NULL;
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free_interp = false;
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td = curthread;
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maxalign = PAGE_SIZE;
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mapsz = 0;
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@ -968,44 +1024,15 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
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break;
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case PT_INTERP:
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/* Path to interpreter */
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if (phdr[i].p_filesz < 2 ||
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phdr[i].p_filesz > MAXPATHLEN) {
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uprintf("Invalid PT_INTERP\n");
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error = ENOEXEC;
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goto ret;
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}
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if (interp != NULL) {
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uprintf("Multiple PT_INTERP headers\n");
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error = ENOEXEC;
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goto ret;
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}
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interp_name_len = phdr[i].p_filesz;
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if (phdr[i].p_offset > PAGE_SIZE ||
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interp_name_len > PAGE_SIZE - phdr[i].p_offset) {
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VOP_UNLOCK(imgp->vp, 0);
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interp_buf = malloc(interp_name_len + 1, M_TEMP,
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M_WAITOK);
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vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
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error = vn_rdwr(UIO_READ, imgp->vp, interp_buf,
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interp_name_len, phdr[i].p_offset,
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UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
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NOCRED, NULL, td);
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if (error != 0) {
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uprintf("i/o error PT_INTERP %d\n",
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error);
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goto ret;
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}
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interp_buf[interp_name_len] = '\0';
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interp = interp_buf;
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} else {
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interp = __DECONST(char *, imgp->image_header) +
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phdr[i].p_offset;
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if (interp[interp_name_len - 1] != '\0') {
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uprintf("Invalid PT_INTERP\n");
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error = ENOEXEC;
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goto ret;
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}
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}
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error = __elfN(get_interp)(imgp, &phdr[i], &interp,
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&free_interp);
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if (error != 0)
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goto ret;
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break;
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case PT_GNU_STACK:
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if (__elfN(nxstack))
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@ -1016,8 +1043,7 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
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}
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}
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brand_info = __elfN(get_brandinfo)(imgp, interp, interp_name_len,
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&osrel, &fctl0);
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brand_info = __elfN(get_brandinfo)(imgp, interp, &osrel, &fctl0);
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if (brand_info == NULL) {
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uprintf("ELF binary type \"%u\" not known.\n",
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hdr->e_ident[EI_OSABI]);
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@ -1238,7 +1264,8 @@ __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
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imgp->proc->p_elf_flags = hdr->e_flags;
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ret:
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free(interp_buf, M_TEMP);
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if (free_interp)
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free(interp, M_TEMP);
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return (error);
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}
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