Re: [PATCH 60/68] prefer memcpy to strcpy
- From
Torsten Bögershausen <tboegi@web.de>
- Date
- Sep 27, 2015, 13:06 UTC
- Message-ID
- <5607E9E4.4010209@web.de>
- In-Reply-To
- <5607D0A9.4000506@web.de>
On 2015-09-27 13.19, René Scharfe wrote:
Show 32 quoted lines
> Am 24.09.2015 um 23:08 schrieb Jeff King:
>> When we already know the length of a string (e.g., because
>> we just malloc'd to fit it), it's nicer to use memcpy than
>> strcpy, as it makes it more obvious that we are not going to
>> overflow the buffer (because the size we pass matches the
>> size in the allocation).
>>
>> This also eliminates calls to strcpy, which make auditing
>> the code base harder.
>>
>> Signed-off-by: Jeff King <peff@peff.net>
>> ---
>> compat/nedmalloc/nedmalloc.c | 5 +++--
>> fast-import.c | 5 +++--
>> revision.c | 2 +-
>> 3 files changed, 7 insertions(+), 5 deletions(-)
>>
>> diff --git a/compat/nedmalloc/nedmalloc.c b/compat/nedmalloc/nedmalloc.c
>> index 609ebba..a0a16eb 100644
>> --- a/compat/nedmalloc/nedmalloc.c
>> +++ b/compat/nedmalloc/nedmalloc.c
>> @@ -957,8 +957,9 @@ char *strdup(const char *s1)
>> {
>> char *s2 = 0;
>> if (s1) {
>> - s2 = malloc(strlen(s1) + 1);
>> - strcpy(s2, s1);
>> + size_t len = strlen(s1) + 1;
>> + s2 = malloc(len);
>> + memcpy(s2, s1, len);
>
> This leaves the last byte uninitialized; it was set to NUL by strcpy() before.len is == strlen() +1, which should cover the NUL:
1 byte extra for NUL is allocated, and memcpy will copy NUL from source. (Or do I miss somethong ?)