Messages in this thread | | | From | Parag Warudkar <> | Date | Sun, 12 Jul 2009 17:54:28 -0400 | Subject | Re: 2.6.31-rc2: BUG: unable to handle kernel NULL pointer dereference |
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On Sun, Jul 12, 2009 at 4:26 PM, Jiri Slaby<jirislaby@gmail.com> wrote: > On 07/12/2009 07:30 PM, Parag Warudkar wrote: >> static void selinux_write_opts(struct seq_file *m, >> 1012 struct security_mnt_opts *opts) >> 1013 { >> 1014 int i; >> 1015 char *prefix; >> 1016 >> 1017 for (i = 0; i < opts->num_mnt_opts; i++) { >> 1018 char *has_comma; >> 1019 >> 1020 if (opts->mnt_opts[i]) >> 1021 has_comma = strchr(opts->mnt_opts[i], ','); >> ^^^^^^^^^^^^^^^^^^^^^^^^^ >> And that is a NULL pointer dereference - but we just checked for >> opts->mnt_opts[i] for not NULL. > > Note, that there is not a NULL dereference. It dereferences 0x40 which > came in as %rdi. Looks like somebody assigned garbage in there.
Ah right - anything < PAGE_SIZE is "NULL" dereference to the kernel.
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