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[PATCH] livepatch: robustify klp_register_patch() API error checking

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  [PATCH] livepatch: robustify klp_register_patch() API error  checking Jiri Kosina <jikos@kernel.org> - 2016-04-07 18:10 +0200
    Re: [PATCH] livepatch: robustify klp_register_patch() API error  checking Josh Poimboeuf <jpoimboe@redhat.com> - 2016-04-07 20:10 +0200
    Re: livepatch: robustify klp_register_patch() API error checking Jessica Yu <jeyu@redhat.com> - 2016-04-07 20:30 +0200
    Re: [PATCH] livepatch: robustify klp_register_patch() API error  checking Jiri Kosina <jikos@kernel.org> - 2016-04-07 22:40 +0200

#1373510 — [PATCH] livepatch: robustify klp_register_patch() API error checking

From: Jiri Kosina <jkosina@suse.cz>

Commit 425595a7fc20 ("livepatch: reuse module loader code to write 
relocations") adds a possibility of dereferncing pointers supplied by the 
consumer of the livepatch API before sanity (NULL) checking them (patch 
and patch->mod).

Spotted by smatch tool.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 kernel/livepatch/core.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index eb5db6e..28c37fa 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -876,6 +876,9 @@ int klp_register_patch(struct klp_patch *patch)
 {
 	int ret;
 
+	if (!patch || !patch->mod)
+		return -EINVAL;
+
 	if (!is_livepatch_module(patch->mod)) {
 		pr_err("module %s is not marked as a livepatch module",
 		       patch->mod->name);
@@ -885,9 +888,6 @@ int klp_register_patch(struct klp_patch *patch)
 	if (!klp_initialized())
 		return -ENODEV;
 
-	if (!patch || !patch->mod)
-		return -EINVAL;
-
 	/*
 	 * A reference is taken on the patch module to prevent it from being
 	 * unloaded.  Right now, we don't allow patch modules to unload since

-- 
Jiri Kosina
SUSE Labs

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#1373632

On Thu, Apr 07, 2016 at 06:06:25PM +0200, Jiri Kosina wrote:
> From: Jiri Kosina <jkosina@suse.cz>
> 
> Commit 425595a7fc20 ("livepatch: reuse module loader code to write 
> relocations") adds a possibility of dereferncing pointers supplied by the 
> consumer of the livepatch API before sanity (NULL) checking them (patch 
> and patch->mod).
> 
> Spotted by smatch tool.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>


-- 
Josh

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#1373642 — Re: livepatch: robustify klp_register_patch() API error checking

+++ Jiri Kosina [07/04/16 18:06 +0200]:
>From: Jiri Kosina <jkosina@suse.cz>
>
>Commit 425595a7fc20 ("livepatch: reuse module loader code to write
>relocations") adds a possibility of dereferncing pointers supplied by the
>consumer of the livepatch API before sanity (NULL) checking them (patch
>and patch->mod).
>
>Spotted by smatch tool.
>
>Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
>Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Acked-by: Jessica Yu <jeyu@redhat.com>

Thank you Jiri!

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#1373728

On Thu, 7 Apr 2016, Jiri Kosina wrote:

> From: Jiri Kosina <jkosina@suse.cz>
> 
> Commit 425595a7fc20 ("livepatch: reuse module loader code to write 
> relocations") adds a possibility of dereferncing pointers supplied by the 
> consumer of the livepatch API before sanity (NULL) checking them (patch 
> and patch->mod).
> 
> Spotted by smatch tool.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Jessica Yu <jeyu@redhat.com>

Pushed out. Thanks,	

-- 
Jiri Kosina
SUSE Labs

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