ccing bpf list On Fri, Jun 21, 2024 at 09:39:33PM +0300, Alexey Dobriyan wrote: > Neither ELF spec not ELF loader require program header to be placed > right after ELF header, but build-id code very much assumes such placement: > > See > > find_get_page(vma->vm_file->f_mapping, 0); > > line and checks against PAGE_SIZE. > > Returns errors for now until someone rewrites build-id parser > to be more inline with load_elf_binary(). > > Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> > --- > > lib/buildid.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > --- a/lib/buildid.c > +++ b/lib/buildid.c > @@ -73,6 +73,13 @@ static int get_build_id_32(const void *page_addr, unsigned char *build_id, > Elf32_Phdr *phdr; > int i; > > + /* > + * FIXME nit, FIXME is usually on the same line as the rest of the comment, otherwise looks good Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx> thanks, jirka > + * Neither ELF spec nor ELF loader require that program headers > + * start immediately after ELF header. > + */ > + if (ehdr->e_phoff != sizeof(Elf32_Ehdr)) > + return -EINVAL; > /* only supports phdr that fits in one page */ > if (ehdr->e_phnum > > (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)) > @@ -98,6 +105,13 @@ static int get_build_id_64(const void *page_addr, unsigned char *build_id, > Elf64_Phdr *phdr; > int i; > > + /* > + * FIXME > + * Neither ELF spec nor ELF loader require that program headers > + * start immediately after ELF header. > + */ > + if (ehdr->e_phoff != sizeof(Elf64_Ehdr)) > + return -EINVAL; > /* only supports phdr that fits in one page */ > if (ehdr->e_phnum > > (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
