lkml.org 
[lkml]   [2000]   [Nov]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    SubjectRe: Modprobe local root exploit
    From
    >>>>> "Chris" == Chris Evans <chris@scary.beasts.org> writes:

    Chris> What's wrong with isalnum() ?

    Hm, must admit that I wasn't 100% sure if that's in the kernel lib or an evil
    gcc expands it inline to some static array lookup. Now I see that it's
    already in the kernel. Do some of you also sometimes wonder why the kernel is
    so big ;-) ?

    OK, so let's go for the isalnum() version, and don't forget to
    #include <linux/ctype.h>
    above...

    Torsten

    For those who joined the program late here's the complete patch:

    --- linux/kernel/kmod.c.orig Tue Sep 26 01:18:55 2000
    +++ linux/kernel/kmod.c Mon Nov 13 19:09:11 2000
    @@ -18,6 +18,7 @@
    #include <linux/config.h>
    #include <linux/sched.h>
    #include <linux/unistd.h>
    +#include <linux/ctype.h>
    #include <linux/smp_lock.h>

    #include <asm/uaccess.h>
    @@ -168,6 +169,19 @@
    static atomic_t kmod_concurrent = ATOMIC_INIT(0);
    #define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
    static int kmod_loop_msg;
    + const char * p;
    +
    + /* For security reasons ensure the requested name consists
    + * only of allowed characters. Especially whitespace and
    + * shell metacharacters might confuse modprobe.
    + */
    + for (p = module_name; *p; p++)
    + {
    + if (isalnum(*p) || *p == '_' || *p == '-')
    + continue;
    +
    + return -EINVAL;
    + }

    /* Don't allow request_module() before the root fs is mounted! */
    if ( ! current->fs->root ) {
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2005-03-22 12:45    [W:0.020 / U:0.260 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site