2006-02-15 20:23:18

by Davi Arnaut

[permalink] [raw]

Subject: [PATCH 1/2] strndup_user, convert (module)

---

Convert kernel/module.c string duplication to strdup_user()

Signed-off-by: Davi Arnaut <[email protected]>
--

diff --git a/kernel/module.c b/kernel/module.c
index 5aad477..d7d428d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1538,7 +1538,6 @@ static struct module *load_module(void _
unsigned int i, symindex = 0, strindex = 0, setupindex, exindex,
exportindex, modindex, obsparmindex, infoindex, gplindex,
crcindex, gplcrcindex, versindex, pcpuindex;
- long arglen;
struct module *mod;
long err = 0;
void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -1655,23 +1654,11 @@ static struct module *load_module(void _
}

/* Now copy in args */
- arglen = strlen_user(uargs);
- if (!arglen) {
- err = -EFAULT;
- goto free_hdr;
- }
- args = kmalloc(arglen, GFP_KERNEL);
- if (!args) {
- err = -ENOMEM;
+ args = strdup_user(uargs);
+ if (IS_ERR(args)) {
+ err = PTR_ERR(args);
goto free_hdr;
}
- if (copy_from_user(args, uargs, arglen) != 0) {
- err = -EFAULT;
- goto free_mod;
- }
-
- /* Userspace could have altered the string after the strlen_user() */
- args[arglen - 1] = '\0';

if (find_module(mod->name)) {
err = -EEXIST;

2006-02-16 19:09:34

by Sergey Vlasov

[permalink] [raw]

Subject: Re: [PATCH 1/2] strndup_user, convert (module)

---

On Wed, 15 Feb 2006 18:23:06 -0300 Davi Arnaut wrote:

> Convert kernel/module.c string duplication to strdup_user()
>
> Signed-off-by: Davi Arnaut <[email protected]>
> --
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 5aad477..d7d428d 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -1538,7 +1538,6 @@ static struct module *load_module(void _
> unsigned int i, symindex = 0, strindex = 0, setupindex, exindex,
> exportindex, modindex, obsparmindex, infoindex, gplindex,
> crcindex, gplcrcindex, versindex, pcpuindex;
> - long arglen;
> struct module *mod;
> long err = 0;
> void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
> @@ -1655,23 +1654,11 @@ static struct module *load_module(void _
> }
>
> /* Now copy in args */
> - arglen = strlen_user(uargs);
> - if (!arglen) {
> - err = -EFAULT;
> - goto free_hdr;
> - }
> - args = kmalloc(arglen, GFP_KERNEL);
> - if (!args) {
> - err = -ENOMEM;
> + args = strdup_user(uargs);

Before your changes the args string was limited by the maximum size
supported by kmalloc(); you have changed the limit to 4096 hardcoded
inside strdup_user(), which is much lower.

> + if (IS_ERR(args)) {
> + err = PTR_ERR(args);
> goto free_hdr;
> }
> - if (copy_from_user(args, uargs, arglen) != 0) {
> - err = -EFAULT;
> - goto free_mod;
> - }
> -
> - /* Userspace could have altered the string after the strlen_user() */
> - args[arglen - 1] = '\0';
>
> if (find_module(mod->name)) {
> err = -EEXIST;

---

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