| |
| /*--------------------------------------------------------------------*/ |
| /*--- User-mode execve() for ELF executables m_ume_elf.c ---*/ |
| /*--------------------------------------------------------------------*/ |
| |
| /* |
| This file is part of Valgrind, a dynamic binary instrumentation |
| framework. |
| |
| Copyright (C) 2000-2015 Julian Seward |
| jseward@acm.org |
| |
| 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. |
| |
| 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. |
| |
| 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. |
| |
| The GNU General Public License is contained in the file COPYING. |
| */ |
| |
| #if defined(VGO_linux) || defined(VGO_solaris) |
| |
| #include "pub_core_basics.h" |
| #include "pub_core_vki.h" |
| |
| #include "pub_core_aspacemgr.h" // various mapping fns |
| #include "pub_core_debuglog.h" |
| #include "pub_core_libcassert.h" // VG_(exit), vg_assert |
| #include "pub_core_libcbase.h" // VG_(memcmp), etc |
| #include "pub_core_libcprint.h" |
| #include "pub_core_libcfile.h" // VG_(open) et al |
| #include "pub_core_machine.h" // VG_ELF_CLASS (XXX: which should be moved) |
| #include "pub_core_mallocfree.h" // VG_(malloc), VG_(free) |
| #include "pub_core_syscall.h" // VG_(strerror) |
| #include "pub_core_ume.h" // self |
| |
| #include "priv_ume.h" |
| |
| /* --- !!! --- EXTERNAL HEADERS start --- !!! --- */ |
| #if defined(VGO_linux) |
| # define _GNU_SOURCE |
| # define _FILE_OFFSET_BITS 64 |
| #endif |
| /* This is for ELF types etc, and also the AT_ constants. */ |
| #include <elf.h> |
| #if defined(VGO_solaris) |
| # include <sys/fasttrap.h> // PT_SUNWDTRACE_SIZE |
| #endif |
| /* --- !!! --- EXTERNAL HEADERS end --- !!! --- */ |
| |
| |
| #if VG_WORDSIZE == 8 |
| #define ESZ(x) Elf64_##x |
| #elif VG_WORDSIZE == 4 |
| #define ESZ(x) Elf32_##x |
| #else |
| #error VG_WORDSIZE needs to ==4 or ==8 |
| #endif |
| |
| struct elfinfo |
| { |
| ESZ(Ehdr) e; |
| ESZ(Phdr) *p; |
| Int fd; |
| }; |
| |
| static void check_mmap(SysRes res, Addr base, SizeT len) |
| { |
| if (sr_isError(res)) { |
| VG_(printf)("valgrind: mmap(0x%llx, %lld) failed in UME " |
| "with error %lu (%s).\n", |
| (ULong)base, (Long)len, |
| sr_Err(res), VG_(strerror)(sr_Err(res)) ); |
| if (sr_Err(res) == VKI_EINVAL) { |
| VG_(printf)("valgrind: this can be caused by executables with " |
| "very large text, data or bss segments.\n"); |
| } |
| VG_(exit)(1); |
| } |
| } |
| |
| /*------------------------------------------------------------*/ |
| /*--- Loading ELF files ---*/ |
| /*------------------------------------------------------------*/ |
| |
| static |
| struct elfinfo *readelf(Int fd, const HChar *filename) |
| { |
| SysRes sres; |
| struct elfinfo *e = VG_(malloc)("ume.re.1", sizeof(*e)); |
| Int phsz; |
| |
| e->fd = fd; |
| |
| sres = VG_(pread)(fd, &e->e, sizeof(e->e), 0); |
| if (sr_isError(sres) || sr_Res(sres) != sizeof(e->e)) { |
| VG_(printf)("valgrind: %s: can't read ELF header: %s\n", |
| filename, VG_(strerror)(sr_Err(sres))); |
| goto bad; |
| } |
| |
| if (VG_(memcmp)(&e->e.e_ident[0], ELFMAG, SELFMAG) != 0) { |
| VG_(printf)("valgrind: %s: bad ELF magic number\n", filename); |
| goto bad; |
| } |
| if (e->e.e_ident[EI_CLASS] != VG_ELF_CLASS) { |
| VG_(printf)("valgrind: wrong ELF executable class " |
| "(eg. 32-bit instead of 64-bit)\n"); |
| goto bad; |
| } |
| if (e->e.e_ident[EI_DATA] != VG_ELF_DATA2XXX) { |
| VG_(printf)("valgrind: executable has wrong endian-ness\n"); |
| goto bad; |
| } |
| if (!(e->e.e_type == ET_EXEC || e->e.e_type == ET_DYN)) { |
| VG_(printf)("valgrind: this is not an executable\n"); |
| goto bad; |
| } |
| |
| if (e->e.e_machine != VG_ELF_MACHINE) { |
| VG_(printf)("valgrind: executable is not for " |
| "this architecture\n"); |
| goto bad; |
| } |
| |
| if (e->e.e_phentsize != sizeof(ESZ(Phdr))) { |
| VG_(printf)("valgrind: sizeof ELF Phdr wrong\n"); |
| goto bad; |
| } |
| |
| phsz = sizeof(ESZ(Phdr)) * e->e.e_phnum; |
| e->p = VG_(malloc)("ume.re.2", phsz); |
| |
| sres = VG_(pread)(fd, e->p, phsz, e->e.e_phoff); |
| if (sr_isError(sres) || sr_Res(sres) != phsz) { |
| VG_(printf)("valgrind: can't read phdr: %s\n", |
| VG_(strerror)(sr_Err(sres))); |
| VG_(free)(e->p); |
| goto bad; |
| } |
| |
| return e; |
| |
| bad: |
| VG_(free)(e); |
| return NULL; |
| } |
| |
| /* Map an ELF file. Returns the brk address. */ |
| static |
| ESZ(Addr) mapelf(struct elfinfo *e, ESZ(Addr) base) |
| { |
| Int i; |
| SysRes res; |
| ESZ(Addr) elfbrk = 0; |
| |
| for (i = 0; i < e->e.e_phnum; i++) { |
| ESZ(Phdr) *ph = &e->p[i]; |
| ESZ(Addr) addr, brkaddr; |
| ESZ(Word) memsz; |
| |
| if (ph->p_type != PT_LOAD) |
| continue; |
| |
| addr = ph->p_vaddr+base; |
| memsz = ph->p_memsz; |
| brkaddr = addr+memsz; |
| |
| if (brkaddr > elfbrk) |
| elfbrk = brkaddr; |
| } |
| |
| for (i = 0; i < e->e.e_phnum; i++) { |
| ESZ(Phdr) *ph = &e->p[i]; |
| ESZ(Addr) addr, bss, brkaddr; |
| ESZ(Off) off; |
| ESZ(Word) filesz; |
| ESZ(Word) memsz; |
| unsigned prot = 0; |
| |
| if (ph->p_type != PT_LOAD) |
| continue; |
| |
| if (ph->p_flags & PF_X) prot |= VKI_PROT_EXEC; |
| if (ph->p_flags & PF_W) prot |= VKI_PROT_WRITE; |
| if (ph->p_flags & PF_R) prot |= VKI_PROT_READ; |
| |
| addr = ph->p_vaddr+base; |
| off = ph->p_offset; |
| filesz = ph->p_filesz; |
| bss = addr+filesz; |
| memsz = ph->p_memsz; |
| brkaddr = addr+memsz; |
| |
| // Tom says: In the following, do what the Linux kernel does and only |
| // map the pages that are required instead of rounding everything to |
| // the specified alignment (ph->p_align). (AMD64 doesn't work if you |
| // use ph->p_align -- part of stage2's memory gets trashed somehow.) |
| // |
| // The condition handles the case of a zero-length segment. |
| if (VG_PGROUNDUP(bss)-VG_PGROUNDDN(addr) > 0) { |
| if (0) VG_(debugLog)(0,"ume","mmap_file_fixed_client #1\n"); |
| res = VG_(am_mmap_file_fixed_client)( |
| VG_PGROUNDDN(addr), |
| VG_PGROUNDUP(bss)-VG_PGROUNDDN(addr), |
| prot, /*VKI_MAP_FIXED|VKI_MAP_PRIVATE, */ |
| e->fd, VG_PGROUNDDN(off) |
| ); |
| if (0) VG_(am_show_nsegments)(0,"after #1"); |
| check_mmap(res, VG_PGROUNDDN(addr), |
| VG_PGROUNDUP(bss)-VG_PGROUNDDN(addr)); |
| } |
| |
| // if memsz > filesz, fill the remainder with zeroed pages |
| if (memsz > filesz) { |
| UInt bytes; |
| |
| bytes = VG_PGROUNDUP(brkaddr)-VG_PGROUNDUP(bss); |
| if (bytes > 0) { |
| if (0) VG_(debugLog)(0,"ume","mmap_anon_fixed_client #2\n"); |
| res = VG_(am_mmap_anon_fixed_client)( |
| VG_PGROUNDUP(bss), bytes, |
| prot |
| ); |
| if (0) VG_(am_show_nsegments)(0,"after #2"); |
| check_mmap(res, VG_PGROUNDUP(bss), bytes); |
| } |
| |
| bytes = bss & (VKI_PAGE_SIZE - 1); |
| |
| // The 'prot' condition allows for a read-only bss |
| if ((prot & VKI_PROT_WRITE) && (bytes > 0)) { |
| bytes = VKI_PAGE_SIZE - bytes; |
| VG_(memset)((void *)bss, 0, bytes); |
| } |
| } |
| } |
| |
| return elfbrk; |
| } |
| |
| Bool VG_(match_ELF)(const void *hdr, SizeT len) |
| { |
| const ESZ(Ehdr) *e = hdr; |
| return (len > sizeof(*e)) && VG_(memcmp)(&e->e_ident[0], ELFMAG, SELFMAG) == 0; |
| } |
| |
| |
| /* load_ELF pulls an ELF executable into the address space, prepares |
| it for execution, and writes info about it into INFO. In |
| particular it fills in .init_eip, which is the starting point. |
| |
| Returns zero on success, non-zero (a VKI_E.. value) on failure. |
| |
| The sequence of activities is roughly as follows: |
| |
| - use readelf() to extract program header info from the exe file. |
| |
| - scan the program header, collecting info (not sure what all those |
| info-> fields are, or whether they are used, but still) and in |
| particular looking out fo the PT_INTERP header, which describes |
| the interpreter. If such a field is found, the space needed to |
| hold the interpreter is computed into interp_size. |
| |
| - map the executable in, by calling mapelf(). This maps in all |
| loadable sections, and I _think_ also creates any .bss areas |
| required. mapelf() returns the address just beyond the end of |
| the furthest-along mapping it creates. The executable is mapped |
| starting at EBASE, which is usually read from it (eg, 0x8048000 |
| etc) except if it's a PIE, in which case I'm not sure what |
| happens. |
| |
| The returned address is recorded in info->brkbase as the start |
| point of the brk (data) segment, as it is traditional to place |
| the data segment just after the executable. Neither load_ELF nor |
| mapelf creates the brk segment, though: that is for the caller of |
| load_ELF to attend to. |
| |
| - If the initial phdr scan didn't find any mention of an |
| interpreter (interp == NULL), this must be a statically linked |
| executable, and we're pretty much done. |
| |
| - Otherwise, we need to use mapelf() a second time to load the |
| interpreter. The interpreter can go anywhere, but mapelf() wants |
| to be told a specific address to put it at. So an advisory query |
| is passed to aspacem, asking where it would put an anonymous |
| client mapping of size INTERP_SIZE. That address is then used |
| as the mapping address for the interpreter. |
| |
| - The entry point in INFO is set to the interpreter's entry point, |
| and we're done. */ |
| Int VG_(load_ELF)(Int fd, const HChar* name, /*MOD*/ExeInfo* info) |
| { |
| SysRes sres; |
| struct elfinfo *e; |
| struct elfinfo *interp = NULL; |
| ESZ(Addr) minaddr = ~0; /* lowest mapped address */ |
| ESZ(Addr) maxaddr = 0; /* highest mapped address */ |
| ESZ(Addr) interp_addr = 0; /* interpreter (ld.so) address */ |
| ESZ(Word) interp_size = 0; /* interpreter size */ |
| /* ESZ(Word) interp_align = VKI_PAGE_SIZE; */ /* UNUSED */ |
| Int i; |
| void *entry; |
| ESZ(Addr) ebase = 0; |
| # if defined(VGO_solaris) |
| ESZ(Addr) thrptr_addr = 0; |
| # endif |
| |
| # if defined(HAVE_PIE) |
| ebase = info->exe_base; |
| # endif |
| |
| e = readelf(fd, name); |
| |
| if (e == NULL) |
| return VKI_ENOEXEC; |
| |
| /* The kernel maps position-independent executables at TASK_SIZE*2/3; |
| duplicate this behavior as close as we can. */ |
| if (e->e.e_type == ET_DYN && ebase == 0) { |
| ebase = VG_PGROUNDDN(info->exe_base |
| + (info->exe_end - info->exe_base) * 2 / 3); |
| /* We really don't want to load PIEs at zero or too close. It |
| works, but it's unrobust (NULL pointer reads and writes |
| become legit, which is really bad) and causes problems for |
| exp-ptrcheck, which assumes all numbers below 1MB are |
| nonpointers. So, hackily, move it above 1MB. */ |
| /* Later .. it appears ppc32-linux tries to put [vdso] at 1MB, |
| which totally screws things up, because nothing else can go |
| there. The size of [vdso] is around 2 or 3 pages, so bump |
| the hacky load addess along by 8 * VKI_PAGE_SIZE to be safe. */ |
| /* Later .. on mips64 we can't use 0x108000, because mapelf will |
| fail. */ |
| # if defined(VGP_mips64_linux) |
| if (ebase < 0x100000) |
| ebase = 0x100000; |
| # else |
| vg_assert(VKI_PAGE_SIZE >= 4096); /* stay sane */ |
| ESZ(Addr) hacky_load_address = 0x100000 + 8 * VKI_PAGE_SIZE; |
| if (ebase < hacky_load_address) |
| ebase = hacky_load_address; |
| # endif |
| |
| # if defined(VGO_solaris) |
| /* Record for later use in AT_BASE. */ |
| info->interp_offset = ebase; |
| # endif |
| } |
| |
| info->phnum = e->e.e_phnum; |
| info->entry = e->e.e_entry + ebase; |
| info->phdr = 0; |
| info->stack_prot = VKI_PROT_READ|VKI_PROT_WRITE|VKI_PROT_EXEC; |
| |
| for (i = 0; i < e->e.e_phnum; i++) { |
| ESZ(Phdr) *ph = &e->p[i]; |
| |
| switch(ph->p_type) { |
| case PT_PHDR: |
| info->phdr = ph->p_vaddr + ebase; |
| # if defined(VGO_solaris) |
| info->real_phdr_present = True; |
| # endif |
| break; |
| |
| case PT_LOAD: |
| if (ph->p_vaddr < minaddr) |
| minaddr = ph->p_vaddr; |
| if (ph->p_vaddr+ph->p_memsz > maxaddr) |
| maxaddr = ph->p_vaddr+ph->p_memsz; |
| break; |
| |
| # if defined(VGO_solaris) |
| case PT_SUNWDTRACE: |
| if (ph->p_memsz < PT_SUNWDTRACE_SIZE || |
| (ph->p_flags & (PF_R | PF_W | PF_X)) != (PF_R | PF_W | PF_X)) { |
| VG_(printf)("valgrind: m_ume.c: too small SUNWDTRACE size\n"); |
| return VKI_ENOEXEC; |
| } |
| |
| info->init_thrptr = ph->p_vaddr + ebase; |
| break; |
| # endif |
| |
| case PT_INTERP: { |
| HChar *buf = VG_(malloc)("ume.LE.1", ph->p_filesz+1); |
| Int j; |
| Int intfd; |
| Int baseaddr_set; |
| |
| VG_(pread)(fd, buf, ph->p_filesz, ph->p_offset); |
| buf[ph->p_filesz] = '\0'; |
| |
| sres = VG_(open)(buf, VKI_O_RDONLY, 0); |
| if (sr_isError(sres)) { |
| VG_(printf)("valgrind: m_ume.c: can't open interpreter\n"); |
| VG_(exit)(1); |
| } |
| intfd = sr_Res(sres); |
| |
| interp = readelf(intfd, buf); |
| if (interp == NULL) { |
| VG_(printf)("valgrind: m_ume.c: can't read interpreter\n"); |
| return 1; |
| } |
| VG_(free)(buf); |
| |
| baseaddr_set = 0; |
| for (j = 0; j < interp->e.e_phnum; j++) { |
| ESZ(Phdr) *iph = &interp->p[j]; |
| ESZ(Addr) end; |
| |
| # if defined(VGO_solaris) |
| if (iph->p_type == PT_SUNWDTRACE) { |
| if (iph->p_memsz < PT_SUNWDTRACE_SIZE || |
| (iph->p_flags & (PF_R | PF_W | PF_X)) |
| != (PF_R | PF_W | PF_X)) { |
| VG_(printf)("valgrind: m_ume.c: too small SUNWDTRACE size\n"); |
| return VKI_ENOEXEC; |
| } |
| |
| /* Store the thrptr value into a temporary because we do not |
| know yet where the interpreter is mapped. */ |
| thrptr_addr = iph->p_vaddr; |
| } |
| # endif |
| |
| if (iph->p_type != PT_LOAD || iph->p_memsz == 0) |
| continue; |
| |
| if (!baseaddr_set) { |
| interp_addr = iph->p_vaddr; |
| /* interp_align = iph->p_align; */ /* UNUSED */ |
| baseaddr_set = 1; |
| } |
| |
| /* assumes that all segments in the interp are close */ |
| end = (iph->p_vaddr - interp_addr) + iph->p_memsz; |
| |
| if (end > interp_size) |
| interp_size = end; |
| } |
| break; |
| } |
| |
| # if defined(PT_GNU_STACK) || defined(PT_SUNWSTACK) |
| # if defined(PT_GNU_STACK) |
| /* Android's elf.h doesn't appear to have PT_GNU_STACK. */ |
| case PT_GNU_STACK: |
| # endif |
| # if defined(PT_SUNWSTACK) |
| /* Solaris-specific program header. */ |
| case PT_SUNWSTACK: |
| # endif |
| if ((ph->p_flags & PF_X) == 0) info->stack_prot &= ~VKI_PROT_EXEC; |
| if ((ph->p_flags & PF_W) == 0) info->stack_prot &= ~VKI_PROT_WRITE; |
| if ((ph->p_flags & PF_R) == 0) info->stack_prot &= ~VKI_PROT_READ; |
| break; |
| # endif |
| |
| # if defined(PT_SUNW_SYSSTAT) |
| /* Solaris-specific program header which requires link-time support. */ |
| case PT_SUNW_SYSSTAT: |
| VG_(unimplemented)("Support for program header PT_SUNW_SYSSTAT."); |
| break; |
| # endif |
| # if defined(PT_SUNW_SYSSTAT_ZONE) |
| /* Solaris-specific program header which requires link-time support. */ |
| case PT_SUNW_SYSSTAT_ZONE: |
| VG_(unimplemented)("Support for program header PT_SUNW_SYSSTAT_ZONE."); |
| break; |
| # endif |
| |
| default: |
| // do nothing |
| break; |
| } |
| } |
| |
| if (info->phdr == 0) |
| info->phdr = minaddr + ebase + e->e.e_phoff; |
| |
| if (info->exe_base != info->exe_end) { |
| if (minaddr >= maxaddr || |
| (minaddr + ebase < info->exe_base || |
| maxaddr + ebase > info->exe_end)) { |
| VG_(printf)("Executable range %p-%p is outside the\n" |
| "acceptable range %p-%p\n", |
| (char *)minaddr + ebase, (char *)maxaddr + ebase, |
| (char *)info->exe_base, (char *)info->exe_end); |
| return VKI_ENOMEM; |
| } |
| } |
| |
| info->brkbase = mapelf(e, ebase); /* map the executable */ |
| |
| if (info->brkbase == 0) |
| return VKI_ENOMEM; |
| |
| if (interp != NULL) { |
| /* reserve a chunk of address space for interpreter */ |
| MapRequest mreq; |
| Addr advised; |
| Bool ok; |
| |
| /* Don't actually reserve the space. Just get an advisory |
| indicating where it would be allocated, and pass that to |
| mapelf(), which in turn asks aspacem to do some fixed maps at |
| the specified address. This is a bit of hack, but it should |
| work because there should be no intervening transactions with |
| aspacem which could cause those fixed maps to fail. |
| |
| Placement policy is: |
| |
| if the interpreter asks to be loaded at zero |
| ignore that and put it wherever we like (mappings at zero |
| are bad news) |
| else |
| try and put it where it asks for, but if that doesn't work, |
| just put it anywhere. |
| */ |
| if (interp_addr == 0) { |
| mreq.rkind = MAny; |
| mreq.start = 0; |
| mreq.len = interp_size; |
| } else { |
| mreq.rkind = MHint; |
| mreq.start = interp_addr; |
| mreq.len = interp_size; |
| } |
| |
| advised = VG_(am_get_advisory)( &mreq, True/*client*/, &ok ); |
| |
| if (!ok) { |
| /* bomb out */ |
| SysRes res = VG_(mk_SysRes_Error)(VKI_EINVAL); |
| if (0) VG_(printf)("reserve for interp: failed\n"); |
| check_mmap(res, (Addr)interp_addr, interp_size); |
| /*NOTREACHED*/ |
| } |
| |
| (void)mapelf(interp, (ESZ(Addr))advised - interp_addr); |
| |
| VG_(close)(interp->fd); |
| |
| entry = (void *)(advised - interp_addr + interp->e.e_entry); |
| |
| info->interp_offset = advised - interp_addr; |
| # if defined(VGO_solaris) |
| if (thrptr_addr) |
| info->init_thrptr = thrptr_addr + info->interp_offset; |
| # endif |
| |
| VG_(free)(interp->p); |
| VG_(free)(interp); |
| } else { |
| entry = (void *)(ebase + e->e.e_entry); |
| |
| # if defined(VGO_solaris) |
| if (e->e.e_type == ET_DYN) |
| info->ldsoexec = True; |
| # endif |
| } |
| |
| info->exe_base = minaddr + ebase; |
| info->exe_end = maxaddr + ebase; |
| |
| #if defined(VGP_ppc64be_linux) |
| /* On PPC64BE, ELF ver 1, a func ptr is represented by a TOC entry ptr. |
| This TOC entry contains three words; the first word is the function |
| address, the second word is the TOC ptr (r2), and the third word |
| is the static chain value. */ |
| info->init_ip = ((ULong*)entry)[0]; |
| info->init_toc = ((ULong*)entry)[1]; |
| info->init_ip += info->interp_offset; |
| info->init_toc += info->interp_offset; |
| #elif defined(VGP_ppc64le_linux) |
| /* On PPC64LE, ELF ver 2. API doesn't use a func ptr */ |
| info->init_ip = (Addr)entry; |
| info->init_toc = 0; /* meaningless on this platform */ |
| #else |
| info->init_ip = (Addr)entry; |
| info->init_toc = 0; /* meaningless on this platform */ |
| #endif |
| VG_(free)(e->p); |
| VG_(free)(e); |
| |
| return 0; |
| } |
| |
| #endif // defined(VGO_linux) || defined(VGO_solaris) |
| |
| /*--------------------------------------------------------------------*/ |
| /*--- end ---*/ |
| /*--------------------------------------------------------------------*/ |
