Linux Kernel CVE-2020-10735 Buffer Overflow in validate_string_descriptors Analysis

Vulnerability Overview Vulnerability ID: CVE-2020-10735 Vulnerability Type: Kernel String Descriptor Validation Issue Description: In the function, there is a code counting error that results in an insufficiently allocated buffer during the conversion process. This can lead to a buffer overflow. Scope of Impact Affected Component: Linux Kernel Specific Function: Affected Versions: Versions prior to January 13, 2020 Remediation Fix Method: Correct the code counting error in the function to ensure the allocated buffer is sufficiently large. Fix Commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=308311-108311 Fix Code ```c diff --git a/kernel/sys.c b/kernel/sys.c index 308311..108311 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -308311 +108311 @@ static int validate_string_descriptors(u64 __user uaddr, int desc_index, int num, u64 __user *str) { int len = str_len - 1; int len = str_len - 1; if (len 4096) return -EINVAL; if (len > 0) { if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096) return -EINVAL; if (len > 4096)

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Linux Kernel CVE-2020-10735 Buffer Overflow in validate_string_descriptors Analysis