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Memory Safety
Memory safety is the state of being protected from various software bugs and security vulnerabilities when dealing with memory access, such as buffer overflows and dangling pointers. For example, Java is said to be memory-safe because its runtime error detection checks array bounds and pointer dereferences. In contrast, C and C++ allow arbitrary pointer arithmetic with pointers implemented as direct memory addresses with no provision for bounds checking, and thus are potentially memory-unsafe. History Memory errors were first considered in the context of resource management (computing) and time-sharing systems, in an effort to avoid problems such as fork bombs. Developments were mostly theoretical until the Morris worm, which exploited a buffer overflow in fingerd. The field of computer security developed quickly thereafter, escalating with multitudes of new attacks such as the return-to-libc attack and defense techniques such as the non-executable stack and ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Software Bugs
A software bug is a design defect ( bug) in computer software. A computer program with many or serious bugs may be described as ''buggy''. The effects of a software bug range from minor (such as a misspelled word in the user interface) to severe (such as frequent crashing). In 2002, a study commissioned by the US Department of Commerce's National Institute of Standards and Technology concluded that "software bugs, or errors, are so prevalent and so detrimental that they cost the US economy an estimated $59 billion annually, or about 0.6 percent of the gross domestic product". Since the 1950s, some computer systems have been designed to detect or auto-correct various software errors during operations. History Terminology ''Mistake metamorphism'' (from Greek ''meta'' = "change", ''morph'' = "form") refers to the evolution of a defect in the final stage of software deployment. Transformation of a ''mistake'' committed by an analyst in the early stages of the softwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Return-to-libc Attack
A "return-to-libc" attack is a computer security attack usually starting with a buffer overflow in which a subroutine return address on a call stack is replaced by an address of a subroutine that is already present in the process executable memory, bypassing the no-execute bit feature (if present) and ridding the attacker of the need to inject their own code. The first example of this attack in the wild was contributed by Alexander Peslyak on the Bugtraq mailing list in 1997. On POSIX-compliant operating systems the C standard library ("libc") is commonly used to provide a standard runtime environment for programs written in the C programming language. Although the attacker could make the code return anywhere, libc is the most likely target, as it is almost always linked to the program, and it provides useful calls for an attacker (such as the system function used to execute shell commands). Protection from return-to-libc attacks A non-executable stack can prevent some buffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foreign Function Interface
A foreign function interface (FFI) is a mechanism by which a program written in one programming language can call routines or make use of services written or compiled in another one. An FFI is often used in contexts where calls are made into a binary dynamic-link library. Naming The term comes from the specification for Common Lisp, which explicitly refers to the programming language feature enabling for inter-language calls as such; the term is also often used officially by the interpreter and compiler documentation for Haskell, Rust, PHP, Python, and LuaJIT ( Lua). Other languages use other terminology: Ada has ''language bindings'', while Java has '' Java Native Interface'' (JNI) or '' Java Native Access'' (JNA). Foreign function interface has become generic terminology for mechanisms which provide such services. Operation The primary function of a foreign function interface is to mate the semantics and calling conventions of one programming language (the ''host'' lan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pointer (computer Science)
In computer science, a pointer is an object in many programming languages that stores a memory address. This can be that of another value located in computer memory, or in some cases, that of memory-mapped computer hardware. A pointer ''references'' a location in memory, and obtaining the value stored at that location is known as ''dereferencing'' the pointer. As an analogy, a page number in a book's index could be considered a pointer to the corresponding page; dereferencing such a pointer would be done by flipping to the page with the given page number and reading the text found on that page. The actual format and content of a pointer variable is dependent on the underlying computer architecture. Using pointers significantly improves performance for repetitive operations, like traversing iterable data structures (e.g. strings, lookup tables, control tables, linked lists, and tree structures). In particular, it is often much cheaper in time and space to copy and dereferen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garbage Collection (computer Science)
In computer science, garbage collection (GC) is a form of automatic memory management. The ''garbage collector'' attempts to reclaim memory that was allocated by the program, but is no longer referenced; such memory is called ''garbage (computer science), garbage''. Garbage collection was invented by American computer scientist John McCarthy (computer scientist), John McCarthy around 1959 to simplify manual memory management in Lisp (programming language), Lisp. Garbage collection relieves the programmer from doing manual memory management, where the programmer specifies what objects to de-allocate and return to the memory system and when to do so. Other, similar techniques include stack-based memory allocation, stack allocation, region inference, and memory ownership, and combinations thereof. Garbage collection may take a significant proportion of a program's total processing time, and affect computer performance, performance as a result. Resources other than memory, such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Management
Memory management (also dynamic memory management, dynamic storage allocation, or dynamic memory allocation) is a form of Resource management (computing), resource management applied to computer memory. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed. This is critical to any advanced computer system where more than a single Process (computing), process might be underway at any time. Several methods have been devised that increase the effectiveness of memory management. Virtual memory systems separate the memory addresses used by a process from actual physical addresses, allowing separation of processes and increasing the size of the virtual address space beyond the available amount of Random-access memory, RAM using paging or swapping to secondary storage. The quality of the virtual memory manager can have an extensive effect on overall system C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Like Shooting Fish In A Barrel
In English, the word ''like'' has a very flexible range of uses, ranging from conventional to non-standard. It can be used as a noun, verb, adverb, adjective, preposition, particle, conjunction, hedge, filler, quotative, and semi-suffix. Uses Comparisons ''Like'' is one of the words in the English language that can introduce a simile (a stylistic device comparing two dissimilar ideas). It can be used as a preposition, as in "He runs ''like'' a cheetah"; it can also be used as a suffix, as in "She acts very child-''like''. It can also be used in non-simile comparisons such as, "She has a dog ''like'' ours". As a conjunction ''Like'' is often used in place of the subordinating conjunction ''as'', or ''as if''. Examples: * They look ''like'' they have been having fun. * They look ''as if'' they have been having fun. Many people became aware of the two options in 1954, when a famous ad campaign for Winston cigarettes introduced the slogan " Winston tastes good—like a ci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sudo
() is a shell (computing), shell command (computing), command on Unix-like operating systems that enables a user to run a program with the security privileges of another user, by default the superuser. It originally stood for "superuser do", as that was all it did, and this remains its most common usage; however, the official Sudo project page lists it as "su 'do. The current Linux manual pages define as "substitute user", making the correct meaning of "substitute user, do", because can run a command as other users as well. Unlike the similar command Su (Unix), su, users must, by default, supply their own password for authentication, rather than the password of the target user. After authentication, and if the configuration file (typically #Configuration, /etc/sudoers) permits the user access, the system invokes the requested command. The configuration file offers detailed access permissions, including enabling commands only from the invoking terminal; requiring a password p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heartbleed
Heartbleed is a security bug in some outdated versions of the OpenSSL cryptography library, which is a widely used implementation of the Transport Layer Security (TLS) protocol. It was introduced into the software in 2012 and publicly disclosed in April 2014. Heartbleed could be exploited regardless of whether the vulnerable OpenSSL instance is running as a TLS server or client. It resulted from improper input validation (due to a missing bounds check) in the implementation of the TLS heartbeat extension. Thus, the bug's name derived from ''heartbeat''. The vulnerability was classified as a buffer over-read, a situation where more data can be read than should be allowed. Heartbleed was registered in the Common Vulnerabilities and Exposures database as . The federal Canadian Cyber Incident Response Centre issued a security bulletin advising system administrators about the bug. A fixed version of OpenSSL was released on 7 April 2014, on the same day Heartbleed was publicly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromium (web Browser)
Chromium is a free and open-source web browser project, primarily developed and maintained by Google. It is a widely-used codebase, providing the vast majority of source code, code for Google Chrome and many other browsers, including Microsoft Edge, Samsung Internet, and Opera (web browser), Opera. The code is also used by several application framework, app frameworks. Licensing Chromium is a free and open-source software project. The Google-authored portion is shared under the BSD licenses#3-clause license ("BSD License 2.0", "Revised BSD License", "New BSD License", or "Modified BSD License"), 3-clause BSD license. Third party dependencies are subject to a variety of licenses, including MIT License, MIT, GNU Lesser General Public License, LGPL, Ms-PL, and an Mozilla Public License, MPL/GNU General Public License, GPL/GNU Lesser General Public License, LGPL multi-licensing, tri-license. This licensing permits any party to compiler, build the codebase and share the resulting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Google
Google LLC (, ) is an American multinational corporation and technology company focusing on online advertising, search engine technology, cloud computing, computer software, quantum computing, e-commerce, consumer electronics, and artificial intelligence (AI). It has been referred to as "the most powerful company in the world" by the BBC and is one of the world's List of most valuable brands, most valuable brands. Google's parent company, Alphabet Inc., is one of the five Big Tech companies alongside Amazon (company), Amazon, Apple Inc., Apple, Meta Platforms, Meta, and Microsoft. Google was founded on September 4, 1998, by American computer scientists Larry Page and Sergey Brin. Together, they own about 14% of its publicly listed shares and control 56% of its stockholder voting power through super-voting stock. The company went public company, public via an initial public offering (IPO) in 2004. In 2015, Google was reorganized as a wholly owned subsidiary of Alphabet Inc. Go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft
Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The early 1980s and home computers, rise of personal computers through software like Windows, and the company has since expanded to Internet services, cloud computing, video gaming and other fields. Microsoft is the List of the largest software companies, largest software maker, one of the Trillion-dollar company, most valuable public U.S. companies, and one of the List of most valuable brands, most valuable brands globally. Microsoft was founded by Bill Gates and Paul Allen to develop and sell BASIC interpreters for the Altair 8800. It rose to dominate the personal computer operating system market with MS-DOS in the mid-1980s, followed by Windows. During the 41 years from 1980 to 2021 Microsoft released 9 versions of MS-DOS with a median frequen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
