diff options
| -rw-r--r-- | trunk/ChangeLog.cross | 5 | ||||
| -rw-r--r-- | trunk/src/gather.c | 121 |
2 files changed, 80 insertions, 46 deletions
diff --git a/trunk/ChangeLog.cross b/trunk/ChangeLog.cross index 0427584..62f7f26 100644 --- a/trunk/ChangeLog.cross +++ b/trunk/ChangeLog.cross @@ -4,6 +4,11 @@ 2006-11-28 Mark Shinwell <shinwell@codesourcery.com> + * src/gather.c (maybe_pie): New. + (gather_func): Use it. + + 2006-11-28 Mark Shinwell <shinwell@codesourcery.com> + * src/canonicalize.c: Add prelink.h include directive. Use wrap_readlink and wrap_lstat64. * src/prelink.h: Declare wrap_readlink. diff --git a/trunk/src/gather.c b/trunk/src/gather.c index 9219fdf..8163fe2 100644 --- a/trunk/src/gather.c +++ b/trunk/src/gather.c @@ -673,6 +673,77 @@ add_dir_to_dirlist (const char *name, dev_t dev, int flags) return 0; } +/* Determine if a buffer holding an ELF header and program header + table may be that of a position-independent executable. */ +static int +maybe_pie (unsigned char *e_ident, int big_endian, int sixty_four) +{ + uint16_t num_phdrs; + uint16_t phdr; + size_t p_type_offset; + size_t phnum_offset; + unsigned char *phdr_table; + unsigned char *this_phdr; + + if (sixty_four) + { + uint64_t phdr_offset; + + p_type_offset = offsetof (Elf64_Phdr, p_type); + phnum_offset = offsetof (Elf64_Ehdr, e_phnum); + if (big_endian) + phdr_offset = buf_read_ube64 (&e_ident [offsetof (Elf64_Ehdr, + e_phoff)]); + else + phdr_offset = buf_read_ule64 (&e_ident [offsetof (Elf64_Ehdr, + e_phoff)]); + phdr_table = e_ident + phdr_offset; + } + else + { + uint32_t phdr_offset; + + p_type_offset = offsetof (Elf32_Phdr, p_type); + phnum_offset = offsetof (Elf32_Ehdr, e_phnum); + if (big_endian) + phdr_offset = buf_read_ube32 (&e_ident [offsetof (Elf32_Ehdr, + e_phoff)]); + else + phdr_offset = buf_read_ule32 (&e_ident [offsetof (Elf32_Ehdr, + e_phoff)]); + phdr_table = e_ident + phdr_offset; + } + + this_phdr = phdr_table; + + if (big_endian) + num_phdrs = buf_read_ube16 (&e_ident [phnum_offset]); + else + num_phdrs = buf_read_ule16 (&e_ident [phnum_offset]); + + for (phdr = 0; phdr < num_phdrs; phdr++) + { + unsigned char *p_type_start = this_phdr + p_type_offset; + uint32_t p_type; + + if (big_endian) + p_type = buf_read_ube32 (p_type_start); + else + p_type = buf_read_ule32 (p_type_start); + + if (p_type == PT_PHDR) + return 1; + + /* Any PT_PHDR entry must come before any PT_LOAD entry. */ + if (p_type == PT_LOAD) + return 0; + + this_phdr += sixty_four ? sizeof (Elf64_Phdr) : sizeof (Elf32_Phdr); + } + + return 0; +} + static int gather_func (const char *name, const struct stat64 *st, int type, struct FTW *ftwp) @@ -772,17 +843,7 @@ make_unprelinkable: goto make_unprelinkable; else if (e_ident [EI_CLASS] == ELFCLASS32) { - if (e_ident [offsetof (Elf32_Ehdr, e_phoff)] - == sizeof (Elf32_Ehdr) - && memcmp (e_ident + offsetof (Elf32_Ehdr, e_phoff) + 1, - "\0\0\0", 3) == 0 - && (e_ident [offsetof (Elf32_Ehdr, e_phnum)] - || e_ident [offsetof (Elf32_Ehdr, e_phnum) + 1]) - && e_ident [sizeof (Elf32_Ehdr) - + offsetof (Elf32_Phdr, p_type)] == PT_PHDR - && memcmp (e_ident + sizeof (Elf32_Ehdr) - + offsetof (Elf32_Phdr, p_type) + 1, - "\0\0\0", 3) == 0) + if (maybe_pie (e_ident, 0, 0)) { maybe_pie: dso = fdopen_dso (fd, name); @@ -799,17 +860,7 @@ maybe_pie: } else if (e_ident [EI_CLASS] == ELFCLASS64) { - if (e_ident [offsetof (Elf64_Ehdr, e_phoff)] - == sizeof (Elf64_Ehdr) - && memcmp (e_ident + offsetof (Elf64_Ehdr, e_phoff) + 1, - "\0\0\0\0\0\0\0", 7) == 0 - && (e_ident [offsetof (Elf64_Ehdr, e_phnum)] - || e_ident [offsetof (Elf64_Ehdr, e_phnum) + 1]) - && e_ident [sizeof (Elf64_Ehdr) - + offsetof (Elf64_Phdr, p_type)] == PT_PHDR - && memcmp (e_ident + sizeof (Elf64_Ehdr) - + offsetof (Elf64_Phdr, p_type) + 1, - "\0\0\0", 3) == 0) + if (maybe_pie (e_ident, 0, 1)) goto maybe_pie; goto close_it; } @@ -826,35 +877,13 @@ maybe_pie: goto make_unprelinkable; else if (e_ident [EI_CLASS] == ELFCLASS32) { - if (e_ident [offsetof (Elf32_Ehdr, e_phoff) + 3] - == sizeof (Elf32_Ehdr) - && memcmp (e_ident + offsetof (Elf32_Ehdr, e_phoff), - "\0\0\0", 3) == 0 - && (e_ident [offsetof (Elf32_Ehdr, e_phnum)] - || e_ident [offsetof (Elf32_Ehdr, e_phnum) + 1]) - && e_ident [sizeof (Elf32_Ehdr) - + offsetof (Elf32_Phdr, p_type) + 3] - == PT_PHDR - && memcmp (e_ident + sizeof (Elf32_Ehdr) - + offsetof (Elf32_Phdr, p_type), - "\0\0\0", 3) == 0) + if (maybe_pie (e_ident, 1, 0)) goto maybe_pie; goto close_it; } else if (e_ident [EI_CLASS] == ELFCLASS64) { - if (e_ident [offsetof (Elf64_Ehdr, e_phoff) + 7] - == sizeof (Elf64_Ehdr) - && memcmp (e_ident + offsetof (Elf64_Ehdr, e_phoff), - "\0\0\0\0\0\0\0", 7) == 0 - && (e_ident [offsetof (Elf64_Ehdr, e_phnum)] - || e_ident [offsetof (Elf64_Ehdr, e_phnum) + 1]) - && e_ident [sizeof (Elf64_Ehdr) - + offsetof (Elf64_Phdr, p_type) + 3] - == PT_PHDR - && memcmp (e_ident + sizeof (Elf64_Ehdr) - + offsetof (Elf64_Phdr, p_type), - "\0\0\0", 3) == 0) + if (maybe_pie (e_ident, 1, 1)) goto maybe_pie; goto close_it; } |