| Message ID | 1390347398-6490-1-git-send-email-fdmanana@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Tue, Jan 21, 2014 at 11:36:38PM +0000, Filipe David Borba Manana wrote: > The buffer size argument passed to snprintf must account for the > trailing null byte added by snprintf, and it returns a value >= then > sizeof(buffer) when the string can't fit in the buffer. > > Since our buffer has a size of 64 characters, and the maximum orphan > name we can generate is 63 characters wide, we must pass 64 as the > buffer size to snprintf, and not 63. > > Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> JFYI, I have a patch to do the same plus cleans the code around, but it's part of a bigger series that's in testing atm, so I haven't sent it yet. Consider it Reviewed-by: David Sterba <dsterba@suse.cz> I'll update my version. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 84aed2f..27edc5e 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -1336,7 +1336,7 @@ static int gen_unique_name(struct send_ctx *sctx, return -ENOMEM; while (1) { - len = snprintf(tmp, sizeof(tmp) - 1, "o%llu-%llu-%llu", + len = snprintf(tmp, sizeof(tmp), "o%llu-%llu-%llu", ino, gen, idx); if (len >= sizeof(tmp)) { /* should really not happen */
The buffer size argument passed to snprintf must account for the trailing null byte added by snprintf, and it returns a value >= then sizeof(buffer) when the string can't fit in the buffer. Since our buffer has a size of 64 characters, and the maximum orphan name we can generate is 63 characters wide, we must pass 64 as the buffer size to snprintf, and not 63. Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com> --- fs/btrfs/send.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)