CVE-2021-46932

In the Linux kernel, the following vulnerability has been resolved:

Input: appletouch - initialize work before device registration

Syzbot has reported warning in __flush_work(). This warning is caused by work->func == NULL, which means missing work initialization.

This may happen, since input_dev->close() calls cancel_work_sync(&dev->work), but dev->work initalization happens after input_register_device() call.

So this patch moves dev->work initialization before registering input device

Weakness

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable’s type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://git.kernel.org/stable/c/292d2ac61fb0d9276a0f7b7ce4f50426f2a1c99f
• https://git.kernel.org/stable/c/975774ea7528b489930b76a77ffc4d5379b95ff2
• https://git.kernel.org/stable/c/9f329d0d6c91142cf0ad08d23c72dd195db2633c
• https://git.kernel.org/stable/c/9f3ccdc3f6ef10084ceb3a47df0961bec6196fd0
• https://git.kernel.org/stable/c/a02e1404e27855089d2b0a0acc4652c2ce65fe46
• https://git.kernel.org/stable/c/d1962f263a176f493400b8f91bfbf2bfedce951e
• https://git.kernel.org/stable/c/d2cb2bf39a6d17ef4bdc0e59c1a35cf5751ad8f4
• https://git.kernel.org/stable/c/e79ff8c68acb1eddf709d3ac84716868f2a91012