On Sun, Mar 03, 2019 at 04:23:53PM +0100, Ingo Schwarze wrote:
> Hi,
>
> Benjamin Baier wrote on Sat, Mar 02, 2019 at 10:10:40AM +0100:
>
> > On malloc error symtab is unmapped, so proceeding on will lead
> > to a NULL pointer dereference.
> > When malloc fails we should return like the MMAP case does.
>
> while i'm certainly not experienced with nm(1), this change looks
> correct to me. OK to commit?
>
> Note that returning implies that the program might attempt to process
> further files, which is of dubious value: it is likely to fail, too,
> and in the unlikely case of success, that's maybe even worse: the
> output from subsequent files might cause the user to miss the error
> message about the malloc failure... But given that mmap(2) failure
> already behaves like that, switching to just err(3) out on resource
> exhaustion looks like a larger change which i'm not planning to
> push for, even though it would make sense to me.
>
> Here is the patch again, in standard format.
ok,
-Otto
>
> Yours
> Ingo
>
>
> Index: nm.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/nm/nm.c,v
> retrieving revision 1.53
> diff -p -U8 -r1.53 nm.c
> --- nm.c 27 Oct 2017 16:47:08 -0000 1.53
> +++ nm.c 3 Mar 2019 15:12:28 -0000
> @@ -376,16 +376,17 @@ show_symtab(off_t off, u_long len, const
> MMAP(symtab, len, PROT_READ, MAP_PRIVATE|MAP_FILE, fileno(fp), off);
> if (symtab == MAP_FAILED)
> return (1);
>
> namelen = sizeof(ar_head.ar_name);
> if ((p = malloc(sizeof(ar_head.ar_name))) == NULL) {
> warn("%s: malloc", name);
> MUNMAP(symtab, len);
> + return (1);
> }
>
> printf("\nArchive index:\n");
> num = betoh32(*symtab);
> strtab = (char *)(symtab + num + 1);
> for (ps = symtab + 1; num--; ps++, strtab += strlen(strtab) + 1) {
> if (fseeko(fp, betoh32(*ps), SEEK_SET)) {
> warn("%s: fseeko", name);
>
