diff options
Diffstat (limited to 'linux-user/elfload.c')
| -rw-r--r-- | linux-user/elfload.c | 326 |
1 files changed, 270 insertions, 56 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index f6022fd704..bf8c1bd253 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -12,6 +12,7 @@ #include "qemu/guest-random.h" #include "qemu/units.h" #include "qemu/selfmap.h" +#include "qapi/error.h" #ifdef _ARCH_PPC64 #undef ARCH_DLINFO @@ -1521,6 +1522,39 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, #include "elf.h" +/* We must delay the following stanzas until after "elf.h". */ +#if defined(TARGET_AARCH64) + +static bool arch_parse_elf_property(uint32_t pr_type, uint32_t pr_datasz, + const uint32_t *data, + struct image_info *info, + Error **errp) +{ + if (pr_type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { + if (pr_datasz != sizeof(uint32_t)) { + error_setg(errp, "Ill-formed GNU_PROPERTY_AARCH64_FEATURE_1_AND"); + return false; + } + /* We will extract GNU_PROPERTY_AARCH64_FEATURE_1_BTI later. */ + info->note_flags = *data; + } + return true; +} +#define ARCH_USE_GNU_PROPERTY 1 + +#else + +static bool arch_parse_elf_property(uint32_t pr_type, uint32_t pr_datasz, + const uint32_t *data, + struct image_info *info, + Error **errp) +{ + g_assert_not_reached(); +} +#define ARCH_USE_GNU_PROPERTY 0 + +#endif + struct exec { unsigned int a_info; /* Use macros N_MAGIC, etc for access */ @@ -2372,6 +2406,150 @@ void probe_guest_base(const char *image_name, abi_ulong guest_loaddr, "@ 0x%" PRIx64 "\n", (uint64_t)guest_base); } +enum { + /* The string "GNU\0" as a magic number. */ + GNU0_MAGIC = const_le32('G' | 'N' << 8 | 'U' << 16), + NOTE_DATA_SZ = 1 * KiB, + NOTE_NAME_SZ = 4, + ELF_GNU_PROPERTY_ALIGN = ELF_CLASS == ELFCLASS32 ? 4 : 8, +}; + +/* + * Process a single gnu_property entry. + * Return false for error. + */ +static bool parse_elf_property(const uint32_t *data, int *off, int datasz, + struct image_info *info, bool have_prev_type, + uint32_t *prev_type, Error **errp) +{ + uint32_t pr_type, pr_datasz, step; + + if (*off > datasz || !QEMU_IS_ALIGNED(*off, ELF_GNU_PROPERTY_ALIGN)) { + goto error_data; + } + datasz -= *off; + data += *off / sizeof(uint32_t); + + if (datasz < 2 * sizeof(uint32_t)) { + goto error_data; + } + pr_type = data[0]; + pr_datasz = data[1]; + data += 2; + datasz -= 2 * sizeof(uint32_t); + step = ROUND_UP(pr_datasz, ELF_GNU_PROPERTY_ALIGN); + if (step > datasz) { + goto error_data; + } + + /* Properties are supposed to be unique and sorted on pr_type. */ + if (have_prev_type && pr_type <= *prev_type) { + if (pr_type == *prev_type) { + error_setg(errp, "Duplicate property in PT_GNU_PROPERTY"); + } else { + error_setg(errp, "Unsorted property in PT_GNU_PROPERTY"); + } + return false; + } + *prev_type = pr_type; + + if (!arch_parse_elf_property(pr_type, pr_datasz, data, info, errp)) { + return false; + } + + *off += 2 * sizeof(uint32_t) + step; + return true; + + error_data: + error_setg(errp, "Ill-formed property in PT_GNU_PROPERTY"); + return false; +} + +/* Process NT_GNU_PROPERTY_TYPE_0. */ +static bool parse_elf_properties(int image_fd, + struct image_info *info, + const struct elf_phdr *phdr, + char bprm_buf[BPRM_BUF_SIZE], + Error **errp) +{ + union { + struct elf_note nhdr; + uint32_t data[NOTE_DATA_SZ / sizeof(uint32_t)]; + } note; + + int n, off, datasz; + bool have_prev_type; + uint32_t prev_type; + + /* Unless the arch requires properties, ignore them. */ + if (!ARCH_USE_GNU_PROPERTY) { + return true; + } + + /* If the properties are crazy large, that's too bad. */ + n = phdr->p_filesz; + if (n > sizeof(note)) { + error_setg(errp, "PT_GNU_PROPERTY too large"); + return false; + } + if (n < sizeof(note.nhdr)) { + error_setg(errp, "PT_GNU_PROPERTY too small"); + return false; + } + + if (phdr->p_offset + n <= BPRM_BUF_SIZE) { + memcpy(¬e, bprm_buf + phdr->p_offset, n); + } else { + ssize_t len = pread(image_fd, ¬e, n, phdr->p_offset); + if (len != n) { + error_setg_errno(errp, errno, "Error reading file header"); + return false; + } + } + + /* + * The contents of a valid PT_GNU_PROPERTY is a sequence + * of uint32_t -- swap them all now. + */ +#ifdef BSWAP_NEEDED + for (int i = 0; i < n / 4; i++) { + bswap32s(note.data + i); + } +#endif + + /* + * Note that nhdr is 3 words, and that the "name" described by namesz + * immediately follows nhdr and is thus at the 4th word. Further, all + * of the inputs to the kernel's round_up are multiples of 4. + */ + if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 || + note.nhdr.n_namesz != NOTE_NAME_SZ || + note.data[3] != GNU0_MAGIC) { + error_setg(errp, "Invalid note in PT_GNU_PROPERTY"); + return false; + } + off = sizeof(note.nhdr) + NOTE_NAME_SZ; + + datasz = note.nhdr.n_descsz + off; + if (datasz > n) { + error_setg(errp, "Invalid note size in PT_GNU_PROPERTY"); + return false; + } + + have_prev_type = false; + prev_type = 0; + while (1) { + if (off == datasz) { + return true; /* end, exit ok */ + } + if (!parse_elf_property(note.data, &off, datasz, info, + have_prev_type, &prev_type, errp)) { + return false; + } + have_prev_type = true; + } +} + /* Load an ELF image into the address space. IMAGE_NAME is the filename of the image, to use in error messages. @@ -2391,16 +2569,17 @@ static void load_elf_image(const char *image_name, int image_fd, struct elfhdr *ehdr = (struct elfhdr *)bprm_buf; struct elf_phdr *phdr; abi_ulong load_addr, load_bias, loaddr, hiaddr, error; - int i, retval; - const char *errmsg; + int i, retval, prot_exec; + Error *err = NULL; /* First of all, some simple consistency checks */ - errmsg = "Invalid ELF image for this architecture"; if (!elf_check_ident(ehdr)) { + error_setg(&err, "Invalid ELF image for this architecture"); goto exit_errmsg; } bswap_ehdr(ehdr); if (!elf_check_ehdr(ehdr)) { + error_setg(&err, "Invalid ELF image for this architecture"); goto exit_errmsg; } @@ -2421,22 +2600,54 @@ static void load_elf_image(const char *image_name, int image_fd, mmap_lock(); - /* Find the maximum size of the image and allocate an appropriate - amount of memory to handle that. */ + /* + * Find the maximum size of the image and allocate an appropriate + * amount of memory to handle that. Locate the interpreter, if any. + */ loaddr = -1, hiaddr = 0; info->alignment = 0; for (i = 0; i < ehdr->e_phnum; ++i) { - if (phdr[i].p_type == PT_LOAD) { - abi_ulong a = phdr[i].p_vaddr - phdr[i].p_offset; + struct elf_phdr *eppnt = phdr + i; + if (eppnt->p_type == PT_LOAD) { + abi_ulong a = eppnt->p_vaddr - eppnt->p_offset; if (a < loaddr) { loaddr = a; } - a = phdr[i].p_vaddr + phdr[i].p_memsz; + a = eppnt->p_vaddr + eppnt->p_memsz; if (a > hiaddr) { hiaddr = a; } ++info->nsegs; - info->alignment |= phdr[i].p_align; + info->alignment |= eppnt->p_align; + } else if (eppnt->p_type == PT_INTERP && pinterp_name) { + g_autofree char *interp_name = NULL; + + if (*pinterp_name) { + error_setg(&err, "Multiple PT_INTERP entries"); + goto exit_errmsg; + } + + interp_name = g_malloc(eppnt->p_filesz); + + if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) { + memcpy(interp_name, bprm_buf + eppnt->p_offset, + eppnt->p_filesz); + } else { + retval = pread(image_fd, interp_name, eppnt->p_filesz, + eppnt->p_offset); + if (retval != eppnt->p_filesz) { + goto exit_read; + } + } + if (interp_name[eppnt->p_filesz - 1] != 0) { + error_setg(&err, "Invalid PT_INTERP entry"); + goto exit_errmsg; + } + *pinterp_name = g_steal_pointer(&interp_name); + } else if (eppnt->p_type == PT_GNU_PROPERTY) { + if (!parse_elf_properties(image_fd, info, eppnt, bprm_buf, &err)) { + goto exit_errmsg; + } } } @@ -2490,7 +2701,7 @@ static void load_elf_image(const char *image_name, int image_fd, (ehdr->e_type == ET_EXEC ? MAP_FIXED : 0), -1, 0); if (load_addr == -1) { - goto exit_perror; + goto exit_mmap; } load_bias = load_addr - loaddr; @@ -2525,15 +2736,41 @@ static void load_elf_image(const char *image_name, int image_fd, info->brk = 0; info->elf_flags = ehdr->e_flags; + prot_exec = PROT_EXEC; +#ifdef TARGET_AARCH64 + /* + * If the BTI feature is present, this indicates that the executable + * pages of the startup binary should be mapped with PROT_BTI, so that + * branch targets are enforced. + * + * The startup binary is either the interpreter or the static executable. + * The interpreter is responsible for all pages of a dynamic executable. + * + * Elf notes are backward compatible to older cpus. + * Do not enable BTI unless it is supported. + */ + if ((info->note_flags & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) + && (pinterp_name == NULL || *pinterp_name == 0) + && cpu_isar_feature(aa64_bti, ARM_CPU(thread_cpu))) { + prot_exec |= TARGET_PROT_BTI; + } +#endif + for (i = 0; i < ehdr->e_phnum; i++) { struct elf_phdr *eppnt = phdr + i; if (eppnt->p_type == PT_LOAD) { abi_ulong vaddr, vaddr_po, vaddr_ps, vaddr_ef, vaddr_em, vaddr_len; int elf_prot = 0; - if (eppnt->p_flags & PF_R) elf_prot = PROT_READ; - if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE; - if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC; + if (eppnt->p_flags & PF_R) { + elf_prot |= PROT_READ; + } + if (eppnt->p_flags & PF_W) { + elf_prot |= PROT_WRITE; + } + if (eppnt->p_flags & PF_X) { + elf_prot |= prot_exec; + } vaddr = load_bias + eppnt->p_vaddr; vaddr_po = TARGET_ELF_PAGEOFFSET(vaddr); @@ -2551,7 +2788,7 @@ static void load_elf_image(const char *image_name, int image_fd, image_fd, eppnt->p_offset - vaddr_po); if (error == -1) { - goto exit_perror; + goto exit_mmap; } } @@ -2583,38 +2820,11 @@ static void load_elf_image(const char *image_name, int image_fd, if (vaddr_em > info->brk) { info->brk = vaddr_em; } - } else if (eppnt->p_type == PT_INTERP && pinterp_name) { - char *interp_name; - - if (*pinterp_name) { - errmsg = "Multiple PT_INTERP entries"; - goto exit_errmsg; - } - interp_name = malloc(eppnt->p_filesz); - if (!interp_name) { - goto exit_perror; - } - - if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) { - memcpy(interp_name, bprm_buf + eppnt->p_offset, - eppnt->p_filesz); - } else { - retval = pread(image_fd, interp_name, eppnt->p_filesz, - eppnt->p_offset); - if (retval != eppnt->p_filesz) { - goto exit_perror; - } - } - if (interp_name[eppnt->p_filesz - 1] != 0) { - errmsg = "Invalid PT_INTERP entry"; - goto exit_errmsg; - } - *pinterp_name = interp_name; #ifdef TARGET_MIPS } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) { Mips_elf_abiflags_v0 abiflags; if (eppnt->p_filesz < sizeof(Mips_elf_abiflags_v0)) { - errmsg = "Invalid PT_MIPS_ABIFLAGS entry"; + error_setg(&err, "Invalid PT_MIPS_ABIFLAGS entry"); goto exit_errmsg; } if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) { @@ -2624,7 +2834,7 @@ static void load_elf_image(const char *image_name, int image_fd, retval = pread(image_fd, &abiflags, sizeof(Mips_elf_abiflags_v0), eppnt->p_offset); if (retval != sizeof(Mips_elf_abiflags_v0)) { - goto exit_perror; + goto exit_read; } } bswap_mips_abiflags(&abiflags); @@ -2649,13 +2859,16 @@ static void load_elf_image(const char *image_name, int image_fd, exit_read: if (retval >= 0) { - errmsg = "Incomplete read of file header"; - goto exit_errmsg; + error_setg(&err, "Incomplete read of file header"); + } else { + error_setg_errno(&err, errno, "Error reading file header"); } - exit_perror: - errmsg = strerror(errno); + goto exit_errmsg; + exit_mmap: + error_setg_errno(&err, errno, "Error mapping file"); + goto exit_errmsg; exit_errmsg: - fprintf(stderr, "%s: %s\n", image_name, errmsg); + error_reportf_err(err, "%s: ", image_name); exit(-1); } @@ -2663,26 +2876,27 @@ static void load_elf_interp(const char *filename, struct image_info *info, char bprm_buf[BPRM_BUF_SIZE]) { int fd, retval; + Error *err = NULL; fd = open(path(filename), O_RDONLY); if (fd < 0) { - goto exit_perror; + error_setg_file_open(&err, errno, filename); + error_report_err(err); + exit(-1); } retval = read(fd, bprm_buf, BPRM_BUF_SIZE); if (retval < 0) { - goto exit_perror; + error_setg_errno(&err, errno, "Error reading file header"); + error_reportf_err(err, "%s: ", filename); + exit(-1); } + if (retval < BPRM_BUF_SIZE) { memset(bprm_buf + retval, 0, BPRM_BUF_SIZE - retval); } load_elf_image(filename, fd, info, NULL, bprm_buf); - return; - - exit_perror: - fprintf(stderr, "%s: %s\n", filename, strerror(errno)); - exit(-1); } static int symfind(const void *s0, const void *s1) @@ -2961,7 +3175,7 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) if (elf_interpreter) { info->load_bias = interp_info.load_bias; info->entry = interp_info.entry; - free(elf_interpreter); + g_free(elf_interpreter); } #ifdef USE_ELF_CORE_DUMP |