diff options
Diffstat (limited to 'util/cbfstool/elfheaders.c')
| -rw-r--r-- | util/cbfstool/elfheaders.c | 147 |
1 files changed, 79 insertions, 68 deletions
diff --git a/util/cbfstool/elfheaders.c b/util/cbfstool/elfheaders.c index 0d874a1171..78c864fa52 100644 --- a/util/cbfstool/elfheaders.c +++ b/util/cbfstool/elfheaders.c @@ -128,12 +128,25 @@ static void elf_eident(struct buffer *input, Elf64_Ehdr *ehdr) { - memmove(ehdr->e_ident, input->data, sizeof(ehdr->e_ident)); - input->data += sizeof(ehdr->e_ident); - input->size -= sizeof(ehdr->e_ident); + bgets(input, ehdr->e_ident, sizeof(ehdr->e_ident)); } +static int +check_size(const struct buffer *b, size_t offset, size_t size, const char *desc) +{ + if (size == 0) + return 0; + + if (offset >= buffer_size(b) || (offset + size) > buffer_size(b)) { + ERROR("The file is not large enough for the '%s'. " + "%ld bytes @ offset %zu, input %zu bytes.\n", + desc, size, offset, buffer_size(b)); + return -1; + } + return 0; +} + static void elf_ehdr(struct buffer *input, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64) { @@ -169,7 +182,8 @@ elf_phdr(struct buffer *pinput, Elf64_Phdr *phdr, * pointer the full entsize; rather than get tricky * we just advance it below. */ - struct buffer input = *pinput; + struct buffer input; + buffer_clone(&input, pinput); if (bit64){ phdr->p_type = xdr->get32(&input); phdr->p_flags = xdr->get32(&input); @@ -189,8 +203,7 @@ elf_phdr(struct buffer *pinput, Elf64_Phdr *phdr, phdr->p_flags = xdr->get32(&input); phdr->p_align = xdr->get32(&input); } - pinput->size -= entsize; - pinput->data += entsize; + buffer_seek(pinput, entsize); } static void @@ -228,8 +241,58 @@ elf_shdr(struct buffer *pinput, Elf64_Shdr *shdr, shdr->sh_addralign = xdr->get32(&input); shdr->sh_entsize = xdr->get32(&input); } - pinput->size -= entsize; - pinput->data += entsize; + buffer_seek(pinput, entsize); +} + +static Elf64_Phdr * +phdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64) +{ + struct buffer b; + Elf64_Phdr *phdr; + int i; + + /* cons up an input buffer for the headers. + * Note that the program headers can be anywhere, + * per the ELF spec, You'd be surprised how many ELF + * readers miss this little detail. + */ + buffer_splice(&b, in, ehdr->e_phoff, ehdr->e_phentsize * ehdr->e_phnum); + if (check_size(in, ehdr->e_phoff, buffer_size(&b), "program headers")) + return NULL; + + /* gather up all the phdrs. + * We do them all at once because there is more + * than one loop over all the phdrs. + */ + phdr = calloc(sizeof(*phdr), ehdr->e_phnum); + for (i = 0; i < ehdr->e_phnum; i++) + elf_phdr(&b, &phdr[i], ehdr->e_phentsize, xdr, bit64); + + return phdr; +} + +static Elf64_Shdr * +shdr_read(const struct buffer *in, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64) +{ + struct buffer b; + Elf64_Shdr *shdr; + int i; + + /* cons up an input buffer for the section headers. + * Note that the section headers can be anywhere, + * per the ELF spec, You'd be surprised how many ELF + * readers miss this little detail. + */ + buffer_splice(&b, in, ehdr->e_shoff, ehdr->e_shentsize * ehdr->e_shnum); + if (check_size(in, ehdr->e_shoff, buffer_size(&b), "section headers")) + return NULL; + + /* gather up all the shdrs. */ + shdr = calloc(sizeof(*shdr), ehdr->e_shnum); + for (i = 0; i < ehdr->e_shnum; i++) + elf_shdr(&b, &shdr[i], ehdr->e_shentsize, xdr, bit64); + + return shdr; } /* Get the headers from the buffer. @@ -246,16 +309,13 @@ elf_headers(const struct buffer *pinput, Elf64_Phdr **pphdr, Elf64_Shdr **pshdr) { - int i; struct xdr *xdr = &xdr_le; int bit64 = 0; - struct buffer input = *(struct buffer *)pinput; - struct buffer phdr_buf; - struct buffer shdr_buf; - Elf64_Phdr *phdr; - Elf64_Shdr *shdr; + struct buffer input; + + buffer_clone(&input, pinput); - if (!iself((unsigned char *)pinput->data)) { + if (!iself(buffer_get(pinput))) { ERROR("The stage file is not in ELF format!\n"); return -1; } @@ -280,65 +340,16 @@ elf_headers(const struct buffer *pinput, return -1; } - if (pinput->size < ehdr->e_phoff){ - ERROR("The program header offset is greater than " - "the remaining file size." - "%ld bytes left, program header offset is %ld \n", - pinput->size, ehdr->e_phoff); + *pphdr = phdr_read(pinput, ehdr, xdr, bit64); + if (*pphdr == NULL) return -1; - } - /* cons up an input buffer for the headers. - * Note that the program headers can be anywhere, - * per the ELF spec, You'd be surprised how many ELF - * readers miss this little detail. - */ - phdr_buf.data = &pinput->data[ehdr->e_phoff]; - phdr_buf.size = ehdr->e_phentsize * ehdr->e_phnum; - if (phdr_buf.size > (pinput->size - ehdr->e_phoff)){ - ERROR("The file is not large enough for the program headers." - "%ld bytes left, %ld bytes of headers\n", - pinput->size - ehdr->e_phoff, phdr_buf.size); - return -1; - } - /* gather up all the phdrs. - * We do them all at once because there is more - * than one loop over all the phdrs. - */ - phdr = calloc(sizeof(*phdr), ehdr->e_phnum); - for (i = 0; i < ehdr->e_phnum; i++) - elf_phdr(&phdr_buf, &phdr[i], ehdr->e_phentsize, xdr, bit64); - *pphdr = phdr; if (!pshdr) return 0; - if (pinput->size < ehdr->e_shoff){ - ERROR("The section header offset is greater than " - "the remaining file size." - "%ld bytes left, program header offset is %ld \n", - pinput->size, ehdr->e_shoff); - return -1; - } - /* cons up an input buffer for the section headers. - * Note that the section headers can be anywhere, - * per the ELF spec, You'd be surprised how many ELF - * readers miss this little detail. - */ - shdr_buf.data = &pinput->data[ehdr->e_shoff]; - shdr_buf.size = ehdr->e_shentsize * ehdr->e_shnum; - if (shdr_buf.size > (pinput->size - ehdr->e_shoff)){ - ERROR("The file is not large enough for the section headers." - "%ld bytes left, %ld bytes of headers\n", - pinput->size - ehdr->e_shoff, shdr_buf.size); + *pshdr = shdr_read(pinput, ehdr, xdr, bit64); + if (*pshdr == NULL) return -1; - } - /* gather up all the shdrs. */ - - shdr = calloc(sizeof(*shdr), ehdr->e_shnum); - for (i = 0; i < ehdr->e_shnum; i++) - elf_shdr(&shdr_buf, &shdr[i], ehdr->e_shentsize, xdr, bit64); - *pshdr = shdr; return 0; } - |