That looks better.
Lucas <lu...@sexy.is> wrote:
> Theo Buehler <t...@theobuehler.org> wrote:
> > > - if (pread(fd, phdr, size, ehdr.e_phoff) != size) {
> > > + if ((nr = pread(fd, phdr, size, ehdr.e_phoff)) != -1) {
> >
> > did you intend to check for == -1?
> >
> > > warn("read(%s)", name);
> >
> > should that not say pread?
>
> Indeed, thanks for spotting both things.
>
>
> -----------------------------------------------
> commit 92f58b2a1cd576c3e72303004388ab1e9709e327 (ldd-read-rv)
> from: Lucas <lucas@domain.invalid>
> date: Sat Aug 5 16:34:16 2023 UTC
>
> Check {,p}read return values consistently
>
> Check that read performs a full header read. Explicitly check against -1
> for failure instead of < 0. Split pread error message between error
> handling and short reads. Promote size from int to size_t.
>
> M libexec/ld.so/ldd/ldd.c
>
> diff 194ff02fb6be247e27fe964e901d891d99ec0b74
> 92f58b2a1cd576c3e72303004388ab1e9709e327
> commit - 194ff02fb6be247e27fe964e901d891d99ec0b74
> commit + 92f58b2a1cd576c3e72303004388ab1e9709e327
> blob - 9e8c5065cd843ff36d91efcb868b94ffd4c98365
> blob + 532feb9855a03480c289fa2188768657a4f82e7c
> --- libexec/ld.so/ldd/ldd.c
> +++ libexec/ld.so/ldd/ldd.c
> @@ -96,7 +96,9 @@ doit(char *name)
> {
> Elf_Ehdr ehdr;
> Elf_Phdr *phdr;
> - int fd, i, size, status, interp=0;
> + size_t size;
> + ssize_t nr;
> + int fd, i, status, interp=0;
> char buf[PATH_MAX];
> struct stat st;
> void * dlhandle;
> @@ -118,11 +120,16 @@ doit(char *name)
> return 1;
> }
>
> - if (read(fd, &ehdr, sizeof(ehdr)) < 0) {
> + if ((nr = read(fd, &ehdr, sizeof(ehdr))) == -1) {
> warn("read(%s)", name);
> close(fd);
> return 1;
> }
> + if (nr != sizeof(ehdr)) {
> + warnx("%s: incomplete ELF header", name);
> + close(fd);
> + return 1;
> + }
>
> if (!IS_ELF(ehdr) || ehdr.e_machine != ELF_TARG_MACH) {
> warnx("%s: not an ELF executable", name);
> @@ -140,12 +147,18 @@ doit(char *name)
> err(1, "reallocarray");
> size = ehdr.e_phnum * sizeof(Elf_Phdr);
>
> - if (pread(fd, phdr, size, ehdr.e_phoff) != size) {
> - warn("read(%s)", name);
> + if ((nr = pread(fd, phdr, size, ehdr.e_phoff)) == -1) {
> + warn("pread(%s)", name);
> close(fd);
> free(phdr);
> return 1;
> }
> + if (nr != size) {
> + warnx("%s: incomplete program header", name);
> + close(fd);
> + free(phdr);
> + return 1;
> + }
> close(fd);
>
> for (i = 0; i < ehdr.e_phnum; i++)
>
