Date: Mon, 1 Aug 2005 15:14:13 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-current@freebsd.org Cc: William Josephson <freebsd-D20050727@morphisms.net> Subject: Re: dlinfo/rtld.c bug Message-ID: <200508011514.14346.jhb@FreeBSD.org> In-Reply-To: <20050728000152.871E026@mero.morphisms.net> References: <20050728000152.871E026@mero.morphisms.net>
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On Wednesday 27 July 2005 08:01 pm, William Josephson wrote:
> I've run across a bug in the ELF dynamic linker in FreeBSD 4.x
> and FreeBSD 5.4. Although I haven't had a chance to compile or
> install FreeBSD 6 yet, the bug appears to be in the ELF dynamic
> linker in at least FreeBSD 4 through -CURRENT. The problem is
> that do_search_info in libexec/rtld-elf/rtld.c does not account
> for the space required by Dl_serpath structures with either the
> RTLD_DI_SERINFOSIZE, or the RTLD_DI_SERINFO requests. The
> example program in the dlinfo man page happens to work, but a
> simple loop copying the path strings into a buffer allocated with
> malloc will corrupt the heap. The program below illustrates the
> problem. Given that the arithmetic in do_search_info is easily
> fixed, it might be worth patching before the upcoming release.
>
> #include <link.h>
> #include <dlfcn.h>
> #include <stdio.h>
> #include <stdlib.h>
>
> int
> main(int argc, char *argv[])
> {
> char *s;
> Dl_serinfo *p;
> Dl_serinfo info;
>
> memset(&info, 0, sizeof(info));
> dlinfo(RTLD_SELF, RTLD_DI_SERINFOSIZE, (void*)&info);
> p = malloc(info.dls_size);
> memset(p, 0, info.dls_size);
> p->dls_cnt = info.dls_cnt;
> p->dls_size = info.dls_size;
> dlinfo(RTLD_SELF, RTLD_DI_SERINFO, (void*)p);
> s = p->dls_serpath[p->dls_cnt-1].dls_name;
> s += strlen(s)+1;
> printf("%d %d %d %d %d\n", info.dls_size, (char*)s-(char*)p,
> ((char*)s-(char*)p)-info.dls_size, sizeof(Dl_serpath),
> info.dls_cnt*sizeof(Dl_serpath));
> return 0;
> }
Do you have a patch for this?
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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