Hi,
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.
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);
Regards,
Hans
---
server/reds.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/server/reds.c b/server/reds.c
index 98c8706..5a03043 100644
--- a/server/reds.c
+++ b/server/reds.c
@@ -3952,7 +3952,7 @@ SPICE_GNUC_VISIBLE int spice_server_set_port(SpiceServer
*s, int port)
SPICE_GNUC_VISIBLE void spice_server_set_addr(SpiceServer *s, const char
*addr, int flags)
{
spice_assert(reds == s);
- strncpy(spice_addr, addr, sizeof(spice_addr));
+ strncpy(spice_addr, addr, sizeof(spice_addr)-1);
if (flags & SPICE_ADDR_FLAG_IPV4_ONLY) {
spice_family = PF_INET;
}
@@ -4043,7 +4043,7 @@ SPICE_GNUC_VISIBLE int
spice_server_set_ticket(SpiceServer *s,
taTicket.expiration_time = now + lifetime;
}
if (passwd != NULL) {
- strncpy(taTicket.password, passwd, sizeof(taTicket.password));
+ strncpy(taTicket.password, passwd, sizeof(taTicket.password)-1);
} else {
memset(taTicket.password, 0, sizeof(taTicket.password));
taTicket.expiration_time = 0;
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