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Code Issues 1 Releases Wiki Activity

Add buffer overflow detection to the buffer class

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when the inherent 2GB limit is reached for a single buffer.
This commit is contained in:
bakpakin 2018-01-06 13:25:45 -05:00
parent 605848b217
commit c1fa521b58
4 changed files with 120 additions and 52 deletions
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59
core/buffer.c
View File

@ -64,7 +64,11 @@ void dst_buffer_ensure(DstBuffer *buffer, int32_t capacity) {
/* Adds capacity for enough extra bytes to the buffer. Ensures that the
* next n bytes pushed to the buffer will not cause a reallocation */
void dst_buffer_extra(DstBuffer *buffer, int32_t n) {
int dst_buffer_extra(DstBuffer *buffer, int32_t n) {
/* Check for buffer overflow */
if ((int64_t)n + buffer->count > INT32_MAX) {
return -1;
}
int32_t new_size = buffer->count + n;
if (new_size > buffer->capacity) {
int32_t new_capacity = new_size * 2;
@ -75,55 +79,55 @@ void dst_buffer_extra(DstBuffer *buffer, int32_t n) {
buffer->data = new_data;
buffer->capacity = new_capacity;
}
}
/* Push multiple bytes into the buffer */
void dst_buffer_push_bytes(DstBuffer *buffer, const uint8_t *string, int32_t length) {
int32_t new_size = buffer->count + length;
dst_buffer_ensure(buffer, new_size);
memcpy(buffer->data + buffer->count, string, length);
buffer->count = new_size;
return 0;
}
/* Push a cstring to buffer */
void dst_buffer_push_cstring(DstBuffer *buffer, const char *cstring) {
int dst_buffer_push_cstring(DstBuffer *buffer, const char *cstring) {
int32_t len = 0;
while (cstring[len]) ++len;
dst_buffer_push_bytes(buffer, (const uint8_t *) cstring, len);
return dst_buffer_push_bytes(buffer, (const uint8_t *) cstring, len);
}
/* Push multiple bytes into the buffer */
int dst_buffer_push_bytes(DstBuffer *buffer, const uint8_t *string, int32_t length) {
if (dst_buffer_extra(buffer, length)) return -1;
memcpy(buffer->data + buffer->count, string, length);
buffer->count += length;
return 0;
}
/* Push a single byte to the buffer */
void dst_buffer_push_u8(DstBuffer *buffer, uint8_t byte) {
int32_t new_size = buffer->count + 1;
dst_buffer_ensure(buffer, new_size);
int dst_buffer_push_u8(DstBuffer *buffer, uint8_t byte) {
if (dst_buffer_extra(buffer, 1)) return -1;
buffer->data[buffer->count] = byte;
buffer->count = new_size;
buffer->count++;
return 0;
}
/* Push a 16 bit unsigned integer to the buffer */
void dst_buffer_push_u16(DstBuffer *buffer, uint16_t x) {
int32_t new_size = buffer->count + 1;
dst_buffer_ensure(buffer, new_size);
int dst_buffer_push_u16(DstBuffer *buffer, uint16_t x) {
if (dst_buffer_extra(buffer, 2)) return -1;
buffer->data[buffer->count] = x & 0xFF;
buffer->data[buffer->count + 1] = (x >> 8) & 0xFF;
buffer->count = new_size;
buffer->count += 2;
return 0;
}
/* Push a 32 bit unsigned integer to the buffer */
void dst_buffer_push_u32(DstBuffer *buffer, uint32_t x) {
int32_t new_size = buffer->count + 4;
dst_buffer_ensure(buffer, new_size);
int dst_buffer_push_u32(DstBuffer *buffer, uint32_t x) {
if (dst_buffer_extra(buffer, 4)) return -1;
buffer->data[buffer->count] = x & 0xFF;
buffer->data[buffer->count + 1] = (x >> 8) & 0xFF;
buffer->data[buffer->count + 2] = (x >> 16) & 0xFF;
buffer->data[buffer->count + 3] = (x >> 24) & 0xFF;
buffer->count = new_size;
buffer->count += 4;
return 0;
}
/* Push a 64 bit unsigned integer to the buffer */
void dst_buffer_push_u64(DstBuffer *buffer, uint64_t x) {
int32_t new_size = buffer->count + 8;
dst_buffer_ensure(buffer, new_size);
int dst_buffer_push_u64(DstBuffer *buffer, uint64_t x) {
if (dst_buffer_extra(buffer, 8)) return -1;
buffer->data[buffer->count] = x & 0xFF;
buffer->data[buffer->count + 1] = (x >> 8) & 0xFF;
buffer->data[buffer->count + 2] = (x >> 16) & 0xFF;
@ -132,5 +136,6 @@ void dst_buffer_push_u64(DstBuffer *buffer, uint64_t x) {
buffer->data[buffer->count + 5] = (x >> 40) & 0xFF;
buffer->data[buffer->count + 6] = (x >> 48) & 0xFF;
buffer->data[buffer->count + 7] = (x >> 56) & 0xFF;
buffer->count = new_size;
buffer->count += 8;
return 0;
}

93
core/io.c
View File

@ -6,7 +6,7 @@ DstAbstractType dst_stl_filetype = {
NULL
};
/* Open a a file and return a userdata wrapper arounf the C file API. */
/* Open a a file and return a userdata wrapper around the C file API. */
int dst_stl_open(int32_t argn, Dst *argv, Dst *ret) {
if (argn < 2) {
*ret = dst_cstringv("expected at least 2 arguments");
@ -17,47 +17,104 @@ int dst_stl_open(int32_t argn, Dst *argv, Dst *ret) {
FILE *f;
FILE **fp;
f = fopen((const char *)fname, (const char *)fmode);
if (!f)
dst_c_throwc(vm, "could not open file");
fp = dst_userdata(vm, sizeof(FILE *), &dst_stl_filetype);
if (!f) {
dst_c_throwc("could not open file");
return 1;
}
fp = dst_astract(sizeof(FILE *), &dst_stl_filetype);
*fp = f;
dst_c_return(vm, dst_wrap_userdata(fp));
*ret = dst_wrap_abstract(fp);
return 0;
}
/* Check file argument */
static FILE **checkfile(int32_t argn, Dst *argv, Dst *ret, int32_t n) {
FILE **fp;
if (n >= argn) {
*ret = dst_cstringv("expected stl.file");
return NULL;
}
if (!dst_checktype(argv[n], DST_ABSTRACT)) {
*ret = dst_cstringv("expected stl.file");
return NULL;
}
fp = (FILE **) dst_unwrap_abstract(argv[n]);
if (dst_abstract_type(fp) != &dst_stl_filetype) {
*ret = dst_cstringv("expected stl.file");
return NULL;
}
return fp;
}
/* Check buffer argument */
static DstBuffer *checkbuffer(int32_t argn, Dst *argv, Dst *ret, int32_t n, int optional) {
if (optional && n == argn) {
return dst_buffer(0);
}
if (n >= argn) {
*ret = dst_cstringv("expected buffer");
return NULL;
}
if (!dst_checktype(argv[n], DST_BUFFER)) {
*ret = dst_cstringv("expected buffer");
return NULL;
}
return dst_unwrap_abstract(argv[n]);
}
/* Read an entire file into memory */
int dst_stl_slurp(Dst *vm) {
int dst_stl_slurp(int32_t argn, Dst *argv, Dst *ret) {
DstBuffer *b;
long fsize;
FILE *f;
FILE **fp = dst_check_userdata(vm, 0, &dst_stl_filetype);
if (fp == NULL) dst_c_throwc(vm, "expected file");
if (!dst_check_buffer(vm, 1, &b)) b = dst_buffer(vm, 10);
FILE **fp = checkfile(argn, argv, ret, 0);
if (!fp) return 1;
b = checkbuffer(argn, argv, ret, 1, 1);
if (!b) return 1;
f = *fp;
/* Read whole file */
fseek(f, 0, SEEK_END);
fsize = ftell(f);
fseek(f, 0, SEEK_SET);
if (fsize > INT32_MAX || fsize + b->count > INT32_MAX) {
*ret = dst_cstringv("buffer overflow");
return 1;
}
/* Ensure buffer size */
dst_buffer_ensure(vm, b, b->count + fsize);
dst_buffer_extra(b, fsize);
fread((char *)(b->data + b->count), fsize, 1, f);
b->count += fsize;
dst_c_return(vm, dst_wrap_buffer(b));
/* return */
*ret = dst_wrap_buffer(b);
return 0;
}
/* Read a certain number of bytes into memory */
int dst_stl_read(Dst *vm) {
DstBuffer *b;
FILE *f;
int64_t len;
FILE **fp = dst_check_userdata(vm, 0, &dst_stl_filetype);
if (fp == NULL) dst_c_throwc(vm, "expected file");
if (!(dst_check_integer(vm, 1, &len))) dst_c_throwc(vm, "expected integer");
if (!dst_check_buffer(vm, 2, &b)) b = dst_buffer(vm, 10);
int32_t len;
FILE **fp = checkfile(argn, argv, ret, 0);
if (!fp) return 1;
if (!dst_checktype(argv[1], DST_INTEGER)) {
*ret = dst_cstringv("expected positive integer");
return 1;
}
len = dst_unwrap_integer(argv[1]);
if (len < 0) {
*ret = dst_cstringv("expected positive integer");
return 1;
}
b = checkbuffer(argn, argv, ret, 2, 1);
if (!b) return 1;
f = *fp;
/* Ensure buffer size */
dst_buffer_ensure(vm, b, b->count + len);
if (len + bcount
dst_buffer_extra(b, len);
b->count += fread((char *)(b->data + b->count), len, 1, f) * len;
dst_c_return(vm, dst_wrap_buffer(b));
*ret = dst_wrap_buffer(b);
return 0;
}
/* Write bytes to a file */

6
core/util.h
View File

@ -27,6 +27,12 @@
/* Utils internal to dst. */
/* Type check Dst C Function arguments */
typedef struct DstCSig {
int32_t flags;
DstAbstractType abs;
} DstCSig;
/* Utils */
extern const char dst_base64[65];
int32_t dst_array_calchash(const Dst *array, int32_t len);

14
include/dst/dst.h
View File

@ -47,13 +47,13 @@ DstBuffer *dst_buffer(int32_t capacity);
DstBuffer *dst_buffer_init(DstBuffer *buffer, int32_t capacity);
void dst_buffer_deinit(DstBuffer *buffer);
void dst_buffer_ensure(DstBuffer *buffer, int32_t capacity);
void dst_buffer_extra(DstBuffer *buffer, int32_t n);
void dst_buffer_push_bytes(DstBuffer *buffer, const uint8_t *string, int32_t len);
void dst_buffer_push_cstring(DstBuffer *buffer, const char *cstring);
void dst_buffer_push_u8(DstBuffer *buffer, uint8_t x);
void dst_buffer_push_u16(DstBuffer *buffer, uint16_t x);
void dst_buffer_push_u32(DstBuffer *buffer, uint32_t x);
void dst_buffer_push_u64(DstBuffer *buffer, uint64_t x);
int dst_buffer_extra(DstBuffer *buffer, int32_t n);
int dst_buffer_push_bytes(DstBuffer *buffer, const uint8_t *string, int32_t len);
int dst_buffer_push_cstring(DstBuffer *buffer, const char *cstring);
int dst_buffer_push_u8(DstBuffer *buffer, uint8_t x);
int dst_buffer_push_u16(DstBuffer *buffer, uint16_t x);
int dst_buffer_push_u32(DstBuffer *buffer, uint32_t x);
int dst_buffer_push_u64(DstBuffer *buffer, uint64_t x);
/* Tuple */
#define dst_tuple_raw(t) ((int32_t *)(t) - 2)