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Subject: Fix overflow due to Str.c
Author: Tatsuya Kinoshita <tats@debian.org>
Bug-Chromium: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31397
Bug-Chromium: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31467
Bug-Chromium: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31500
Prevent zero size allocation in Str.c
Prevent unintentional integer overflow in Strcat_charp_n
Prevent unintentional integer overflow in Strgrow
One more fix overflow due to Strgrow
Fix potential overflow due to Str.c
Fix integer overflow due to Strgrow
diff --git a/Str.c b/Str.c
index 61fe3ca..03e0950 100644
--- a/Str.c
+++ b/Str.c
@@ -21,10 +21,12 @@
#ifdef __EMX__ /* or include "fm.h" for HAVE_BCOPY? */
#include <strings.h>
#endif
+#include <limits.h>
#include "Str.h"
#include "myctype.h"
#define INITIAL_STR_SIZE 32
+#define STR_SIZE_MAX (INT_MAX - 1)
#ifdef STR_DEBUG
/* This is obsolete, because "Str" can handle a '\0' character now. */
@@ -48,8 +50,8 @@ Str
Strnew_size(int n)
{
Str x = GC_MALLOC(sizeof(struct _Str));
- if (n < 0)
- n = 0;
+ if (n < 0 || n >= STR_SIZE_MAX)
+ n = STR_SIZE_MAX - 1;
x->ptr = GC_MALLOC_ATOMIC(n + 1);
x->ptr[0] = '\0';
x->area_size = n + 1;
@@ -67,10 +69,13 @@ Strnew_charp(const char *p)
return Strnew();
x = GC_MALLOC(sizeof(struct _Str));
n = strlen(p) + 1;
+ if (n <= 0 || n > STR_SIZE_MAX)
+ n = STR_SIZE_MAX;
x->ptr = GC_MALLOC_ATOMIC(n);
x->area_size = n;
x->length = n - 1;
- bcopy((void *)p, (void *)x->ptr, n);
+ bcopy((void *)p, (void *)x->ptr, n - 1);
+ x->ptr[x->length] = '\0';
return x;
}
@@ -96,6 +101,8 @@ Strnew_charp_n(const char *p, int n)
if (p == NULL)
return Strnew_size(n);
x = GC_MALLOC(sizeof(struct _Str));
+ if (n < 0 || n >= STR_SIZE_MAX)
+ n = STR_SIZE_MAX - 1;
x->ptr = GC_MALLOC_ATOMIC(n + 1);
x->area_size = n + 1;
x->length = n;
@@ -149,15 +156,19 @@ Strcopy_charp(Str x, const char *y)
STR_LENGTH_CHECK(x);
if (y == NULL) {
x->length = 0;
+ x->ptr[0] = '\0';
return;
}
len = strlen(y);
+ if (len < 0 || len >= STR_SIZE_MAX)
+ len = STR_SIZE_MAX - 1;
if (x->area_size < len + 1) {
GC_free(x->ptr);
x->ptr = GC_MALLOC_ATOMIC(len + 1);
x->area_size = len + 1;
}
- bcopy((void *)y, (void *)x->ptr, len + 1);
+ bcopy((void *)y, (void *)x->ptr, len);
+ x->ptr[len] = '\0';
x->length = len;
}
@@ -169,16 +180,19 @@ Strcopy_charp_n(Str x, const char *y, int n)
STR_LENGTH_CHECK(x);
if (y == NULL) {
x->length = 0;
+ x->ptr[0] = '\0';
return;
}
+ if (len < 0 || len >= STR_SIZE_MAX)
+ len = STR_SIZE_MAX - 1;
if (x->area_size < len + 1) {
GC_free(x->ptr);
x->ptr = GC_MALLOC_ATOMIC(len + 1);
x->area_size = len + 1;
}
- bcopy((void *)y, (void *)x->ptr, n);
- x->ptr[n] = '\0';
- x->length = n;
+ bcopy((void *)y, (void *)x->ptr, len);
+ x->ptr[len] = '\0';
+ x->length = len;
}
void
@@ -189,10 +203,18 @@ Strcat_charp_n(Str x, const char *y, int n)
STR_LENGTH_CHECK(x);
if (y == NULL)
return;
+ if (n < 0)
+ n = STR_SIZE_MAX - 1;
newlen = x->length + n + 1;
+ if (newlen <= 0 || newlen > STR_SIZE_MAX) {
+ newlen = STR_SIZE_MAX;
+ n = newlen - x->length - 1;
+ }
if (x->area_size < newlen) {
char *old = x->ptr;
- newlen = newlen * 3 / 2;
+ newlen += newlen / 2;
+ if (newlen <= 0 || newlen > STR_SIZE_MAX)
+ newlen = STR_SIZE_MAX;
x->ptr = GC_MALLOC_ATOMIC(newlen);
x->area_size = newlen;
bcopy((void *)old, (void *)x->ptr, x->length);
@@ -234,12 +256,18 @@ Strgrow(Str x)
{
char *old = x->ptr;
int newlen;
- newlen = x->area_size * 6 / 5;
+ newlen = x->area_size + x->area_size / 5;
if (newlen == x->area_size)
newlen += 2;
+ if (newlen <= 0 || newlen > STR_SIZE_MAX) {
+ newlen = STR_SIZE_MAX;
+ if (x->length + 1 >= newlen)
+ x->length = newlen - 2;
+ }
x->ptr = GC_MALLOC_ATOMIC(newlen);
x->area_size = newlen;
bcopy((void *)old, (void *)x->ptr, x->length);
+ x->ptr[x->length] = '\0';
GC_free(old);
}
@@ -315,6 +343,10 @@ Strdelete(Str s, int pos, int n)
{
int i;
STR_LENGTH_CHECK(s);
+ if (pos < 0 || s->length < pos)
+ return;
+ if (n < 0)
+ n = STR_SIZE_MAX - pos - 1;
if (s->length <= pos + n) {
s->ptr[pos] = '\0';
s->length = pos;
@@ -330,6 +362,8 @@ void
Strtruncate(Str s, int pos)
{
STR_LENGTH_CHECK(s);
+ if (pos < 0 || s->length < pos)
+ return;
s->ptr[pos] = '\0';
s->length = pos;
}
@@ -342,7 +376,7 @@ Strshrink(Str s, int n)
s->length = 0;
s->ptr[0] = '\0';
}
- else {
+ else if (n > 0) {
s->length -= n;
s->ptr[s->length] = '\0';
}
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