On Tue, Nov 19, 2002 at 10:50:42AM +1100, Rusty Russell wrote:
> In message <200211182239.gAIMdBL04074@mort.demon.co.uk> you write:
> > The code (get_sizes) that calculates the amount of space required
> > by the sections assumes that the first one is loaded at address
> > zero (or large alignment) when performing subsequent alignments.
>
> Please test this patch (Petr, contains fix for you too).
Hi Rusty,
I was getting oopses with your patch (due to uninitialized common_length).
With this one (against clean 2.5.48) it works fine (both parport
and vmmon can be insmodded/rmmoded (parport only until it is used by lp,
but that's another story)).
I also modified copy_sections code to verify that we are not
overrunning allocated regions. So now you should get -ENOEXEC instead
of BUG() + corrupted kernel.
Best regards,
Petr Vandrovec
vandrove@vc.cvut.cz
--- linux/kernel/module.c 2002-11-18 14:50:48.000000000 +0100
+++ linux/kernel/module.c 2002-11-19 12:49:37.000000000 +0100
@@ -607,14 +607,17 @@
{
void *dest;
unsigned long *use;
+ unsigned long max;
/* Only copy to init section if there is one */
if (strstr(name, ".init") && mod->module_init) {
dest = mod->module_init;
use = &used->init_size;
+ max = mod->init_size;
} else {
dest = mod->module_core;
use = &used->core_size;
+ max = mod->core_size;
}
/* Align up */
@@ -622,6 +625,9 @@
dest += *use;
*use += sechdr->sh_size;
+ if (*use > max)
+ return ERR_PTR(-ENOEXEC);
+
/* May not actually be in the file (eg. bss). */
if (sechdr->sh_type != SHT_NOBITS)
memcpy(dest, base + sechdr->sh_offset, sechdr->sh_size);
@@ -788,9 +794,10 @@
/* Get the total allocation size of the init and non-init sections */
static struct sizes get_sizes(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
- const char *secstrings)
+ const char *secstrings,
+ unsigned long common_length)
{
- struct sizes ret = { 0, 0 };
+ struct sizes ret = { 0, common_length };
unsigned i;
/* Everything marked ALLOC (this includes the exported
@@ -943,10 +950,9 @@
mod->live = 0;
module_unload_init(mod);
- /* How much space will we need? (Common area in core) */
- sizes = get_sizes(hdr, sechdrs, secstrings);
- common_length = read_commons(hdr, &sechdrs[symindex]);
- sizes.core_size += common_length;
+ /* How much space will we need? (Common area in first) */
+ sizes = get_sizes(hdr, sechdrs, secstrings,
+ common_length = read_commons(hdr, &sechdrs[symindex]));
/* Set these up, and allow archs to manipulate them. */
mod->core_size = sizes.core_size;
@@ -973,7 +979,7 @@
mod->module_core = ptr;
ptr = module_alloc(mod->init_size);
- if (!ptr) {
+ if (!ptr && mod->init_size) {
err = -ENOMEM;
goto free_core;
}
-
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This archive was generated by hypermail 2b29 : Sat Nov 23 2002 - 22:00:27 EST