Hi,
On 11/23/2012 01:42 PM, Christophe Fergeau wrote:
On Fri, Nov 23, 2012 at 01:25:55PM +0100, Hans de Goede wrote:
On 11/23/2012 01:18 PM, Christophe Fergeau wrote:
spice_server_set_ticket and spice_server_set_addr get (library)
user-provided strings as arguments, and copy them to fixed-size
buffers using strncpy. However, if these strings are too long,
the copied string will not be 0-terminated, which will cause issues
later. This commit copies one byte less than the size of the
destination buffer. In both cases, this buffer is a static global
variable, so its memory will be set to 0.
You're being too clever here, this commit message may explain
why explicitly adding the terminating 0 is not necessary even
though it usually is with strncpy, but someone just reading the
code won't know that.
I agree with you that it's quite magic, I just imitated what was done
elsewhere in this file where strncpy is used.
Also because of being way to easy to mis-use strncpy should just
die! So I suggest you redo this patch using snprintf instead
of strncpy, like this:
snprintf(dst, sizeof(dst), "%s", src);
I'll post a followup patch replacing these sizeof()-1 with something else,
though I have a slight preference for adding a spice_strncpy which always
nul-terminate the string. Are you ok with that, or do you prefer that we
use snprintf?
I'm fine with adding a "safe" strcpy but please don't call it
spice_strncpy, as people expect certain (broken) behavior of strncpy, I
would go for the good old bsd strlcpy instead, so add a spice_strlcpy
and add that.
Hmm, doesn't glib have something for this? Aren't we already using glib
in spice-server ? If not it really is time we start using it, as qemu
is using it too...
Regards,
Hans
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