diff options
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/Makefile | 14 | ||||
| -rw-r--r-- | elf/check-textrel.c | 159 |
2 files changed, 173 insertions, 0 deletions
diff --git a/elf/Makefile b/elf/Makefile index 16c947e9b4..5d9dabde9c 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -568,3 +568,17 @@ $(objpfx)tst-array3.out: $(objpfx)tst-array3 --library-path $(rpath-link)$(patsubst %,:%,$(sysdep-library-path)) \ $(objpfx)tst-array3 > $@ cmp $@ tst-array1.exp > /dev/null + + +check-textrel-CFLAGS = -O +$(objpfx)check-textrel: check-textrel.c + $(native-compile) + +ifeq (yes,$(build-shared)) +tests: $(objpfx)check-textrel.out + +$(objpfx)check-textrel.out: $(objpfx)check-textrel + $(dir $<)$(notdir $<) $(common-objpfx)libc.so \ + $(wildcard $(common-objpfx)/*/lib*.so) > $@ +generated += check-textrel check-textrel.out +endif diff --git a/elf/check-textrel.c b/elf/check-textrel.c new file mode 100644 index 0000000000..43e0206ab8 --- /dev/null +++ b/elf/check-textrel.c @@ -0,0 +1,159 @@ +#include <byteswap.h> +#include <elf.h> +#include <endian.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + + +#ifdef BITS + +# define AB(name) _AB (name, BITS) +# define _AB(name, bits) __AB (name, bits) +# define __AB(name, bits) name##bits +# define E(name) _E (name, BITS) +# define _E(name, bits) __E (name, bits) +# define __E(name, bits) Elf##bits##_##name +# define SWAP(val) \ + ({ __typeof (val) __res; \ + if ((ehdr.e_ident[EI_DATA] == ELFDATA2MSB && BYTE_ORDER == LITTLE_ENDIAN \ + || ehdr.e_ident[EI_DATA] == ELFDATA2LSB && BYTE_ORDER == BIG_ENDIAN)\ + && sizeof (val) != 1) \ + { \ + if (sizeof (val) == 2) \ + __res = bswap_16 (val); \ + else if (sizeof (val) == 4) \ + __res = bswap_32 (val); \ + else \ + __res = bswap_64 (val); \ + } \ + else \ + __res = (val); \ + __res; }) + + +static int +AB(handle_file) (const char *fname, int fd) +{ + E(Ehdr) ehdr; + + if (pread (fd, &ehdr, sizeof (ehdr), 0) != sizeof (ehdr)) + { + read_error: + printf ("%s: read error: %m\n", fname); + return 1; + } + + const size_t phnum = SWAP (ehdr.e_phnum); + const size_t phentsize = SWAP (ehdr.e_phentsize); + + /* Read the program header. */ + E(Phdr) *phdr = alloca (phentsize * phnum); + if (pread (fd, phdr, phentsize * phnum, SWAP (ehdr.e_phoff)) + != phentsize * phnum) + goto read_error; + + /* Search for the PT_DYNAMIC entry. */ + size_t cnt; + for (cnt = 0; cnt < phnum; ++cnt) + if (phdr[cnt].p_type == PT_DYNAMIC) + break; + + if (cnt == phnum) + { + printf ("%s: no DYNAMIC segment found\n", fname); + return 1; + } + + /* Read the dynamic segment. */ + size_t pmemsz = SWAP(phdr[cnt].p_memsz); + E(Dyn) *dyn = alloca (pmemsz); + if (pread (fd, dyn, pmemsz, SWAP(phdr[cnt].p_offset)) != pmemsz) + goto read_error; + + /* Search for an DT_TEXTREL entry of DT_FLAGS with the DF_TEXTREL + bit set. */ + for (cnt = 0; (cnt + 1) * sizeof (E(Dyn)) - 1 < pmemsz; ++cnt) + { + if (dyn[cnt].d_tag == DT_NULL) + /* We reached the end. */ + break; + + if (dyn[cnt].d_tag == DT_TEXTREL + || (dyn[cnt].d_tag == DT_FLAGS + && (dyn[cnt].d_un.d_val & DF_TEXTREL) != 0)) + { + /* Urgh! The DSO has text relocations. */ + printf ("%s: text relocations used\n", fname); + return 1; + } + } + + printf ("%s: OK\n", fname); + + return 0; +} + +# undef BITS +#else + +# define BITS 32 +# include "check-textrel.c" + +# define BITS 64 +# include "check-textrel.c" + + +static int +handle_file (const char *fname) +{ + int fd = open (fname, O_RDONLY); + if (fd == -1) + { + printf ("cannot open %s: %m\n", fname); + return 1; + } + + /* Read was is supposed to be the ELF header. Read the initial + bytes to determine whether this is a 32 or 64 bit file. */ + char ident[EI_NIDENT]; + if (read (fd, ident, EI_NIDENT) != EI_NIDENT) + { + printf ("%s: read error: %m\n", fname); + close (fd); + return 1; + } + + if (memcmp (&ident[EI_MAG0], ELFMAG, SELFMAG) != 0) + { + printf ("%s: not an ELF file\n", fname); + close (fd); + return 1; + } + + int result; + if (ident[EI_CLASS] == ELFCLASS64) + result = handle_file64 (fname, fd); + else + result = handle_file32 (fname, fd); + + close (fd); + + return result; +} + + +int +main (int argc, char *argv[]) +{ + int cnt; + int result = 0; + + for (cnt = 1; cnt < argc; ++cnt) + result |= handle_file (argv[cnt]); + + return result; +} +#endif |