2017-04-23 17:24:58

by Naveen N. Rao

Subject: [PATCH] kallsyms: Use bounded strnchr() when parsing string

When parsing for the <module:name> format, we use strchr() to look for
the separator, when we know that the module name can't be longer than
MODULE_NAME_LEN. Enforce the same using strnchr().

Signed-off-by: Naveen N. Rao <[email protected]>
---
kernel/module.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/module.c b/kernel/module.c
index 7eba6dea4f41..d3bd56ed3541 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4017,7 +4017,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)

/* Don't lock: we're in enough trouble already. */
preempt_disable();
- if ((colon = strchr(name, ':')) != NULL) {
+ if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
if ((mod = find_module_all(name, colon - name, false)) != NULL)
ret = mod_find_symname(mod, colon+1);
} else {
--
2.12.1

2017-04-24 02:12:20

by Masami Hiramatsu

Subject: Re: [PATCH] kallsyms: Use bounded strnchr() when parsing string

On Sun, 23 Apr 2017 22:53:43 +0530
"Naveen N. Rao" <[email protected]> wrote:

> When parsing for the <module:name> format, we use strchr() to look for
> the separator, when we know that the module name can't be longer than
> MODULE_NAME_LEN. Enforce the same using strnchr().

Looks good to me :)

Reviewed-by: Masami Hiramatsu <[email protected]>

Thanks,

>
> Signed-off-by: Naveen N. Rao <[email protected]>
> ---
> kernel/module.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/module.c b/kernel/module.c
> index 7eba6dea4f41..d3bd56ed3541 100644
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -4017,7 +4017,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
>
> /* Don't lock: we're in enough trouble already. */
> preempt_disable();
> - if ((colon = strchr(name, ':')) != NULL) {
> + if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
> if ((mod = find_module_all(name, colon - name, false)) != NULL)
> ret = mod_find_symname(mod, colon+1);
> } else {
> --
> 2.12.1
>


--
Masami Hiramatsu <[email protected]>

2017-04-24 21:27:15

by Jessica Yu

Subject: Re: [PATCH] kallsyms: Use bounded strnchr() when parsing string

+++ Naveen N. Rao [23/04/17 22:53 +0530]:
>When parsing for the <module:name> format, we use strchr() to look for
>the separator, when we know that the module name can't be longer than
>MODULE_NAME_LEN. Enforce the same using strnchr().
>
>Signed-off-by: Naveen N. Rao <[email protected]>

Applied, thanks!

Jessica

>---
> kernel/module.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/kernel/module.c b/kernel/module.c
>index 7eba6dea4f41..d3bd56ed3541 100644
>--- a/kernel/module.c
>+++ b/kernel/module.c
>@@ -4017,7 +4017,7 @@ unsigned long module_kallsyms_lookup_name(const char *name)
>
> /* Don't lock: we're in enough trouble already. */
> preempt_disable();
>- if ((colon = strchr(name, ':')) != NULL) {
>+ if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
> if ((mod = find_module_all(name, colon - name, false)) != NULL)
> ret = mod_find_symname(mod, colon+1);
> } else {
>--
>2.12.1
>