Re: [PATCH v3 3/8] securtiy/brute: Detect a brute force attack
From: Randy Dunlap <hidden>
Date: 2021-02-23 20:46:56
Also in:
linux-kselftest, linux-security-module, lkml
On 2/23/21 10:20 AM, John Wood wrote:
Hi, On Sun, Feb 21, 2021 at 06:47:16PM -0800, Randy Dunlap wrote:quoted
Hi-- scripts/kernel-doc does not like these items to be marked as being in kernel-doc notation. scripts/kernel-doc does not recognize them as one of: struct, union, enum, typedef, so it defaults to trying to interpret these as functions, and then says: (I copied these blocks to my test megatest.c source file.) ../src/megatest.c:1214: warning: cannot understand function prototype: 'const u64 BRUTE_EMA_WEIGHT_NUMERATOR = 7; ' ../src/megatest.c:1219: warning: cannot understand function prototype: 'const u64 BRUTE_EMA_WEIGHT_DENOMINATOR = 10; ' ../src/megatest.c:1228: warning: cannot understand function prototype: 'const unsigned char BRUTE_MAX_FAULTS = 200; ' ../src/megatest.c:1239: warning: cannot understand function prototype: 'const unsigned char BRUTE_MIN_FAULTS = 5; ' ../src/megatest.c:1249: warning: cannot understand function prototype: 'const u64 BRUTE_CRASH_PERIOD_THRESHOLD = 30000; ' On 2/21/21 7:49 AM, John Wood wrote:quoted
+/** + * brute_stats_ptr_lock - Lock to protect the brute_stats structure pointer. + */ +static DEFINE_RWLOCK(brute_stats_ptr_lock);quoted
+/** + * BRUTE_EMA_WEIGHT_NUMERATOR - Weight's numerator of EMA. + */ +static const u64 BRUTE_EMA_WEIGHT_NUMERATOR = 7;quoted
+/** + * BRUTE_EMA_WEIGHT_DENOMINATOR - Weight's denominator of EMA. + */ +static const u64 BRUTE_EMA_WEIGHT_DENOMINATOR = 10;quoted
+/** + * BRUTE_MAX_FAULTS - Maximum number of faults. + * + * If a brute force attack is running slowly for a long time, the application + * crash period's EMA is not suitable for the detection. This type of attack + * must be detected using a maximum number of faults. + */ +static const unsigned char BRUTE_MAX_FAULTS = 200;quoted
+/** + * BRUTE_MIN_FAULTS - Minimum number of faults. + * + * The application crash period's EMA cannot be used until a minimum number of + * data has been applied to it. This constraint allows getting a trend when this + * moving average is used. Moreover, it avoids the scenario where an application + * fails quickly from execve system call due to reasons unrelated to a real + * attack. + */ +static const unsigned char BRUTE_MIN_FAULTS = 5;quoted
+/** + * BRUTE_CRASH_PERIOD_THRESHOLD - Application crash period threshold. + * + * The units are expressed in milliseconds. + * + * A fast brute force attack is detected when the application crash period falls + * below this threshold. + */ +static const u64 BRUTE_CRASH_PERIOD_THRESHOLD = 30000;Basically we don't support scalars in kernel-doc notation...So, to keep it commented it would be better to use a normal comment block? /* * Documentation here */ What do you think?
Yes, please, just a normal /* comment block. thanks. -- ~Randy