chp 4: grammar fixes

Author: w3irdrobot

src/chp4/_index.md

@@ -142,7 +142,7 @@ But after finishing the chapter, maybe you'll start viewing memory primarily thr
 * Develop a mental model of memory safety, type safety, and binary exploitation
 * Learn to debug Rust code using Mozilla `rr`[^RR] (an enhanced variant of `gdb`[^GDB])
 * Understand how attackers exploit heap memory corruption bugs, step-by-step
-* Write your first an introductory exploit or two, bypassing modern protections!
+* Write an introductory exploit or two, bypassing modern protections!
 * Understand how Rust actually provides memory safety, including current limitations
 * Understand how modern, language-agnostic exploit mitigations work (and how they can fail)
 

src/chp4/assure_stack_1.md

@@ -75,7 +75,7 @@ Lets visualize how a code snippet uses the stack, to make the push/pop discussio
 
 * We're interested in how this program uses stack memory at runtime, adding the attribute `#[inline(never)]` to ensure the compiler allocates a stack frame each time either `recursive_count_down` or `square` is called.
 
-  * "Inlining" is an opportunistic compiler optimization can avoids function call overhead, including stack frame allocation and caller-register preservation [^Inlining]. It's not always applicable and as programmer we don't directly decide where it is. So forgoing it is a realistic case to prepare for.
+  * "Inlining" is an opportunistic compiler optimization that avoids function call overhead, including stack frame allocation and caller-register preservation [^Inlining]. It's not always applicable and as programmer we don't directly decide where it is. So forgoing it is a realistic case to prepare for.
 
 If run with `cargo run -- 2`, this program outputs:
 

src/chp4/attack_1.md

@@ -80,7 +80,7 @@ Be it C, C++, or `unsafe` Rust.
 
 For a more concrete discussion of memory and type safety, we'll examine three C snippets and visualize the violations therein. Note:
 
-* None of the three snippets are, to the best our knowledge, *exploitable*. These small programs break safety, but not in manner unfortunate enough to enable a break of data-code isolation.
+* None of the three snippets are, to the best our knowledge, *exploitable*. These small programs break safety, but not in amanner unfortunate enough to enable a break of data-code isolation.
 
 This distinction is intensional.
 We're starting by learning to identify bugs, even if innocuous.

src/chp4/sw_stack_1.md

@@ -69,7 +69,7 @@ Both topics are the subjects of entire technical books, so we'll visually diagra
 </p>
 
 Main memory, a physical machine's Random Access Memory (RAM), supports all non-trivial runtime computation.
-The bit-patterns it stores and operates on representations two distinct items:
+The bit-patterns it stores and operates on represent two distinct items:
 
 * **Data** - Variable-length sequences of bytes representing any information: hardcoded strings, colors codes, numbers, entire image and video files, etc. Each byte can be addressed individually, even if word-aligned accesses are often preferable for performance.
 
@@ -114,7 +114,7 @@ Fortunately, we don't have to consider or understand such minutia when programmi
 The jobs of various registers are, by contrast, important for a working mental model.
 In addition to the IP, the two special purpose registers worth noting are:
 
-* The **Stack Pointer (`SP`)** register - the address denoting the bottom of the current stack frame. A stack frame is akin to function's in-RAM "notepad" for computing and saving *function-local* results.
+* The **Stack Pointer (`SP`)** register - the address denoting the bottom of the current stack frame. A stack frame is akin to a function's in-RAM "notepad" for computing and saving *function-local* results.
 
     * In the statement `let x = 3 + 6;`, `x` will be computed using registers, then the value `9` will be stored on the stack[^RegisterAlloc]. This allows the CPU to re-use its small, fixed set of `GP*` registers for new computations when multiple functions are called in a program.
 
@@ -185,7 +185,7 @@ It's important you commit it to memory, pun intended.
 > The kernel runs in "ring 0", the most privileged mode available.
 > It can read/write from/to any processes's memory, directly access hardware, and control special CPU features.
 >
-> Rings 2 and 3 are almost never used in practice[^RingProt].
+> Rings 1 and 2 are almost never used in practice[^RingProt].
 > These modes were intended for device drivers, special programs that allow a kernel to communicate with vendor-specific hardware.
 > In reality most device drivers are loaded directly into the kernel, running alongside it in ring 0 (creating a major OS attack surface[^MSKernBlocklist]).
 >