acct: fix potential integer overflow in encode_comp_t()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: acct: fix potential integer overflow in encode_comp_t() The integer overflow is descripted with following codes: > 317 static comp_t encode_comp_t(u64 value) > 318 { > 319 int exp, rnd; ...... > 341 exp <<= MANTSIZE; > 342 exp += value; > 343 return exp; > 344 } Currently comp_t is defined as type of '__u16', but the variable 'exp' is type of 'int', so overflow would happen when variable 'exp' in line 343 is greater than 65535.

References

• https://git.kernel.org/stable/c/e93f995a591c352d35d89c518c54f790e1537754
• https://git.kernel.org/stable/c/cf60bbca1b83a7e0927e36dbf178328982927886
• https://git.kernel.org/stable/c/1750a0983c455a9b3badd848471fc8d58cb61f67
• https://git.kernel.org/stable/c/a815a3e019456c94b03bd183e7ac22fd29e9e6fd
• https://git.kernel.org/stable/c/6edd0cdee5780fd5f43356b72b29a2a6d48ef6da
• https://git.kernel.org/stable/c/ebe16676e1dcaa4556ec4d36ca40c82e99e88cfa
• https://git.kernel.org/stable/c/2224897d8187dc22a83e05d9361efcccf67bcf12
• https://git.kernel.org/stable/c/0aac6e60c464a5f942f995428e67f8ae1c422250
• https://git.kernel.org/stable/c/c5f31c655bcc01b6da53b836ac951c1556245305