Author: kib Date: Sat Jun 13 18:21:31 2020 New Revision: 362152 URL: https://svnweb.freebsd.org/changeset/base/362152
Log: Fix ldd for PIE binaries after rtld stopped accepting binaries for dlopen. ldd proclaims ET_DYN objects as shared libraries and tries to dlopen(RTLD_TRACE) them to get dependencies. Since PIE binaries are ET_DYN | DF_1_PIE, refusal to dlopen such binaries breaks ldd. Fix it by reading and parsing dynamic segment looking for DF_FLAG_1 and taking DF_1_PIE into account when deciding between binary and library. Reported by: Dewayne Geraghty <dewa...@heuristicsystems.com.au> Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D25257 Modified: head/usr.bin/ldd/ldd.c Modified: head/usr.bin/ldd/ldd.c ============================================================================== --- head/usr.bin/ldd/ldd.c Sat Jun 13 18:19:42 2020 (r362151) +++ head/usr.bin/ldd/ldd.c Sat Jun 13 18:21:31 2020 (r362152) @@ -289,10 +289,18 @@ is_executable(const char *fname, int fd, int *is_shlib #endif Elf_Ehdr elf; } hdr; - int n; + Elf_Phdr phdr, dynphdr; + Elf_Dyn *dynp; + void *dyndata; +#if __ELF_WORD_SIZE > 32 && defined(ELF32_SUPPORTED) + Elf32_Phdr phdr32, dynphdr32; + Elf32_Dyn *dynp32; +#endif + int df1pie, dynamic, i, n; *is_shlib = 0; *type = TYPE_UNKNOWN; + df1pie = 0; if ((n = read(fd, &hdr, sizeof(hdr))) == -1) { warn("%s: can't read program header", fname); @@ -320,8 +328,6 @@ is_executable(const char *fname, int fd, int *is_shlib if ((size_t)n >= sizeof(hdr.elf32) && IS_ELF(hdr.elf32) && hdr.elf32.e_ident[EI_CLASS] == ELFCLASS32) { /* Handle 32 bit ELF objects */ - Elf32_Phdr phdr; - int dynamic, i; dynamic = 0; *type = TYPE_ELF32; @@ -331,13 +337,14 @@ is_executable(const char *fname, int fd, int *is_shlib return (0); } for (i = 0; i < hdr.elf32.e_phnum; i++) { - if (read(fd, &phdr, hdr.elf32.e_phentsize) != - sizeof(phdr)) { + if (read(fd, &phdr32, hdr.elf32.e_phentsize) != + sizeof(phdr32)) { warnx("%s: can't read program header", fname); return (0); } - if (phdr.p_type == PT_DYNAMIC) { + if (phdr32.p_type == PT_DYNAMIC) { dynamic = 1; + dynphdr32 = phdr32; break; } } @@ -346,9 +353,36 @@ is_executable(const char *fname, int fd, int *is_shlib warnx("%s: not a dynamic ELF executable", fname); return (0); } + if (hdr.elf32.e_type == ET_DYN) { + if (lseek(fd, dynphdr32.p_offset, SEEK_SET) == -1) { + warnx("%s: dynamic segment out of range", + fname); + return (0); + } + dyndata = malloc(dynphdr32.p_filesz); + if (dyndata == NULL) { + warn("malloc"); + return (0); + } + if (read(fd, dyndata, dynphdr32.p_filesz) != + (ssize_t)dynphdr32.p_filesz) { + free(dyndata); + warnx("%s: can't read dynamic segment", fname); + return (0); + } + for (dynp32 = dyndata; dynp32->d_tag != DT_NULL; + dynp32++) { + if (dynp32->d_tag != DT_FLAGS_1) + continue; + df1pie = (dynp32->d_un.d_val & DF_1_PIE) != 0; + break; + } + free(dyndata); + if (hdr.elf32.e_ident[EI_OSABI] == ELFOSABI_FREEBSD) { - *is_shlib = 1; + if (!df1pie) + *is_shlib = 1; return (1); } warnx("%s: not a FreeBSD ELF shared object", fname); @@ -362,8 +396,6 @@ is_executable(const char *fname, int fd, int *is_shlib if ((size_t)n >= sizeof(hdr.elf) && IS_ELF(hdr.elf) && hdr.elf.e_ident[EI_CLASS] == ELF_TARG_CLASS) { /* Handle default ELF objects on this architecture */ - Elf_Phdr phdr; - int dynamic, i; dynamic = 0; *type = TYPE_ELF; @@ -380,6 +412,7 @@ is_executable(const char *fname, int fd, int *is_shlib } if (phdr.p_type == PT_DYNAMIC) { dynamic = 1; + dynphdr = phdr; break; } } @@ -388,10 +421,36 @@ is_executable(const char *fname, int fd, int *is_shlib warnx("%s: not a dynamic ELF executable", fname); return (0); } + if (hdr.elf.e_type == ET_DYN) { + if (lseek(fd, dynphdr.p_offset, SEEK_SET) == -1) { + warnx("%s: dynamic segment out of range", + fname); + return (0); + } + dyndata = malloc(dynphdr.p_filesz); + if (dyndata == NULL) { + warn("malloc"); + return (0); + } + if (read(fd, dyndata, dynphdr.p_filesz) != + (ssize_t)dynphdr.p_filesz) { + free(dyndata); + warnx("%s: can't read dynamic segment", fname); + return (0); + } + for (dynp = dyndata; dynp->d_tag != DT_NULL; dynp++) { + if (dynp->d_tag != DT_FLAGS_1) + continue; + df1pie = (dynp->d_un.d_val & DF_1_PIE) != 0; + break; + } + free(dyndata); + switch (hdr.elf.e_ident[EI_OSABI]) { case ELFOSABI_FREEBSD: - *is_shlib = 1; + if (!df1pie) + *is_shlib = 1; return (1); #ifdef __ARM_EABI__ case ELFOSABI_NONE: _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
