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fix buffer overread for len=0 in scan_longn (Martin Castillo)

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This commit is contained in:
leitner 2022-04-11 08:35:54 +00:00
parent e0ebf1e57e
commit d93ddc33b8
3 changed files with 12 additions and 4 deletions
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1
CHANGES
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@ -10,6 +10,7 @@
add cross references to open_* and mmap_* man pages
add fmt_strm_alloca and fmt_strm_malloc man pages
add buffer_init_allocbuf, buffer_init_read, buffer_init_write, buffer_init_read_allocbuf, buffer_init_write_allocbuf
fix buffer overread for len=0 in scan_longn (Martin Castillo)
0.32:
remove OpenBSD #warning (obsd maintainer says no longer needed)

7
scan/scan_long.c
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@ -28,6 +28,13 @@ int main() {
assert(scan_long("9223372036854775807",&i)==19 && i==0x7fffffffffffffffull); // LONG_MAX
assert(scan_long("-9223372036854775808",&i)==20 && i==(long long)0x8000000000000000ull); // LONG_MIN
}
i=42;
assert(scan_longn("7",0,&i)==0 && i==42);
assert(scan_longn("-7",1,&i)==0 && i==42);
assert(scan_longn("+7",1,&i)==0 && i==42);
assert(scan_longn("7",1,&i)==1 && i==7);
assert(scan_longn("-7",2,&i)==2 && i==-7);
assert(scan_longn("+7",2,&i)==2 && i==7);
return 0;
}
#endif

8
scan/scan_longn.c
View File

@ -2,19 +2,19 @@
static const unsigned long maxlong = ((unsigned long)-1)>>1;
size_t scan_longn(const char *src,size_t n,long *dest) {
size_t scan_longn(const char *src,size_t len,long *dest) {
register const char *tmp;
register long int l;
register unsigned char c;
unsigned int neg;
int ok;
if (!n--) return 0;
if (!len) return 0;
tmp=src; l=0; ok=0; neg=0;
switch (*tmp) {
case '-': neg=1; /* fall through */
case '+': ++tmp;
case '+': ++tmp; --len;
}
while (n-->0 && (c=(unsigned char)(*tmp-'0'))<10) {
while (len-->0 && (c=(unsigned char)(*tmp-'0'))<10) {
unsigned long int n;
#if defined(__GNUC__) && (__GNUC__ >= 5)
if (__builtin_mul_overflow(l,10,&n) || __builtin_add_overflow(n,c,&n))